Research ArticleRockburst Characteristics and Mechanisms during SteeplyInclined Thin Veins Mining A Case Study in Zhazixi AntimonyMine China

Yuanjun Ma12 Changwu Liu 1 Fan Wu3 and Xiaolong Li1

1State Key Laboratory of Hydraulic and Mountain River Engineering College of Water Resource and HydropowerSichuan University Chengdu 610065 China2China Gezhouba Group Explosive Co Ltd Chongqing 401121 China3Institute of Disaster Management and Reconstruction Sichuan University-1e Hong Kong Polytechnic UniversityNo 1 Huanghe Road Chengdu 610065 China

Correspondence should be addressed to Changwu Liu liuchangwuscueducn

Received 29 May 2018 Revised 1 September 2018 Accepted 3 October 2018 Published 4 November 2018

Academic Editor Adam Glowacz

Copyright copy 2018 Yuanjun Ma et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

With the increase of mining depth rockbursts have become important safety problems in Zhazixi Antimony Mine whereoverlying strata exceed 560m Due to the small spacing between the steeply inclined veins mining activities have great influenceson rockbursts of adjacent veins In order to study rockburst characteristics and mechanisms in Zhazixi Antimony Mine in situmeasurement field geological survey uniaxial compression tests and numerical simulation are conducted to analyze rockburstproneness and simulate the elastic strain energy accumulation characteristics Consequently rockburst proneness criteria areestablished on the basis of experimental results to propose the necessary lithologic conditions for rockburst aiming to ZhazixiAntimony Mine Rockburst dangerous districts are defined based on high stress concentration and elastic strain energy dis-tribution characteristics in mining process obtained by theory analysis and numerical simulation Accordingly it is suggested thatthrown-type rockbursts mainly occur in massive stibnite of ventilation shafts and stopes where the elastic strain energy exceeds300 kJmiddotmminus3 spalling-type rockbursts generally appear in slate of roadways where the elastic strain energy exceeds 100 kJmiddotmminus3 andejection-type rockbursts arise in different rock masses under a certain condition Last but not the least prediction results arebasically consistent with statistics data of rockburst events after comparative analysis

1 Introduction

A rockburst is a sudden dynamic instability phenomenonunder excavation unloading conditions of high geostressareas [1] As excavation depth increases progressivelyrockburst accidents occur frequently which can leadto schedule delays equipment damage and even life-threatening situations In recent years different kinds ofprojects have suffered from rockbursts eg hydropowerprojects [2 3] tunnels [4 5] and mines [6ndash8] resulting inhuge direct and indirect economic losses It is obviouslybeneficial and significant to acquaint its mechanism inorder to control rockbursts with proper measures

Actually many methods such as case analysis [9] in situstress measurement [10 11] rock mechanics tests [12 13]microseismic monitoring [2 14] numerical simulation[15ndash17] etc have been applied to study rockburst mech-anisms in different projects Although there is no consensuson the mechanism of rockbursts due to complexity andhidden nature of the subsurface geological conditions someachievements of previous researches have thoughtful andprofound effects Driad-Lebeau [18] proposed that struc-turally complete rock combined with high horizontal tec-tonic stresses was responsible for rockbursts Zhou et al [19]demonstrated that preexisting cracks of rock masses werebeneficial to abrupt energy release stored in rock masses

HindawiShock and VibrationVolume 2018 Article ID 3786047 16 pageshttpsdoiorg10115520183786047

coming into being rockbursts under certain conditionsHolub and Petros [20] discussed the thick and integritystrata were contributed to mining-induced seismicity whichwas one of the characteristics of rockburst Lu et al andMeng et al [21 22] indicated geological structures such asfaults and joints brought about stress increase sharplywhich easily lead to rockbursts Yang et al [4] presented highin situ stresses were the main factor that caused strain energyaccumulation and gave rise to rockbursts in the strong rockZhu et al [16] emphasized great importance should be at-tached to rockbursts bought by dynamic disturbance duringunderground mining

However most of the research studies focus on a singleroadway or stope not much attention have been dedicatedto the interaction of adjacent work faces In particularstresses redistribution is extremely complex inuenced byadjacent working faces during steeply inclined veins miningIt should be noted that rockburst mechanisms have not yetbeen illuminated in steeply inclined mine Besides somemeasurements preventing or reducing rockburst disastershave been discovered unreasonable in application Hencein this study the characteristics of rockburst are rst ana-lyzed and rockburst mechanisms are then comprehensivelystudied through rock mechanics experiment theoreticalresearch and numerical simulation in Zhazixi AntimonyMine in China

2 Engineering Background andRockburst Characteristics

21 Engineering Background Zhazixi Antimony Mine islocated in the central of the Xuefeng arc structural beltwhich is an essential Au-Sb-W metallogenic tectonic belt inHunan province China It is hosted by the regional NE-trending Majiaxi fractures (F3) which plays an importantrole in regional ore conduction e deposit has more than70 ore veins and two-thirds of them have industrial ex-ploitation value e ore veins show inverted broom shapewhile the geological characteristics are as follows thinthickness (002mndash1029m) long extent in strike (300ndash1000m) steep dip (60degndash90deg) Furthermore the ore veins aregetting closer as the depth increases (Figure 1) According tothe distance from F3 fault the thin ore veins are divided intothree groups ie no 1ndashno 20 ore veins belong to group Ino 21ndashno 33 ore veins belong to group II and no 34ndashno 44ore veins belong to group III

22 Rockburst Characteristics Considering the specialgeological conditions of ore veins the shallow-holeshrinkage stoping method has been used in Zhazixi Anti-monyMine since 1906 In order to raise economic eciencythe high-grade ore veins such as no 9 ore vein and no 19 orevein were preferred to be mined while the poor ores wereignored In recent years the latent dangers in the miningarea are gradually exposed with the deepening of miningRockbursts occurred rst in a transport roadway when theopening depth reached 560m (minus115m level) Especiallyrockbursts are becoming increasingly frequent as mining

goes deeper According to statistics data there were morethan 30 accidents of rockburst between May 2012 and May2013 At present the maximum mining depth has beenextended to the depth of 650m (minus205m level)

Rockburst mainly occurred in the transport roadwaywhen mining depth was minus115m level where the surroundingrocks were relatively intact sandstone and slate with manyendogenetic cracks (Figure 2) e initial stress equilibriumstate of surrounding rock was disturbed after excavatione tangential stress increased sharply and the radial stressdecreased and tensile cracks extension was accelerated onthe surface of roadway resulting in multilayer lamellarspalling at the spandrel (Figure 3(a)) e thickness ofspalling was less than 2 cm Moreover fresh rock surface wascovered with white rock powder which indicated the elasticstrain energy stored in rock masses was released to crushinternal rock masses without great inuences on the pro-jects e fracture planes were characterized by honeycombcracks

However when mining depth exceeded minus160m levelrockburst mainly occurred in the ventilation shaft or stopewhere the surrounding rocks were stibnite As excavationgone into high go-stress areas the elastic strain energy stored

F1

F2

Palcozoic black shaleand carbonate

Ediacaran moraine-breccias

Upper part of Wuqiangxi Fmtuffaceous and thick bedded santone

Lower part of Wuqiangxi Fmtuffaceous and quartz sanstone

Madiyi Fm slate

Geological boundary

Sb ore body

Number of Sb ore bodiesgroup

I

55deg

325degF1

F2

F2F2

F3

FaultF1

Moving direction of theupper wall and lower wall

F1

Figure 1 Fault block structure stereogram of Zhazixi AntimonyMine

2 Shock and Vibration

in rock masses progressively increased Once conningpressure exceeded compressive strength of rock massesthe rock masses failure mode changed into fragile failurefrom plastic failure accompanied with an instantaneousimpact failure As a result a large amount of rock masseswere ejected or thrown out due to elastic strain energyrelease (Figure 3(b)) bringing great damages to projectsefracture surface was similar to a dome

Based on previous research results many factors areconsidered to cause rockburst high geostress excavating-induced stresses the dynamic disturbance of adjacent orevein mining etc A comprehensive understanding of howdipounderent factors apoundect rockburst is essential for rockburstmechanism and prediction erefore a systematic researchhas been carried out as shown in Figure 4

3 Experimental Studies

31 In Situ Stress Measurements

311 e Measurement Method At present stress reliefmethod by overcoring is one of the in situ stress measuringmethods with high applicability and reliability [23] Itsmeasuring tools include hollow inclusion strain gaugegeological drilling rig and drill pipe of Φ130mm andΦ45mm e drill holes with dipounderent diameters (Φ130mmandΦ45mm) of measurement points separate the core fromthe surrounding rocks which relief the three dimensionalstress In the process of stress relief the core has a littleelastic deformation erefore the in situ stress could becalculated by the elastic theory after hollow inclusion strain

gauge measures the strain elastic deformation valueHowever it must be noted that the measurement pointsshould be set in the in situ stress areas of intact rockmass undisturbed by excavation Generally speaking thedepth of drilling holes should be 3ndash5 times the width of theroadway e procedure of in situ stress measurement isshown in Figure 5

e kx-81 hollow inclusion strain gauges were made byChinese Academy of Geological Sciences (CAGS) It consistsof three groups of resistance strain rosette and each group iscomposed of four strain gauges with 45deg distribution Asingle hollow inclusion strain gauge can measure the threedimensional stress state of a borehole

Considering the in situ stress has been measured inshallow part near the mine [24] four measurement pointsare layout at three levels in deep mining areas of ZhazixiAntimony Mine ie minus115m level (burial depth 560m)minus160m level (burial depth 605m) and minus205m level (burialdepth 650m) respectively

312 In Situ Stress Field Distribution

(1) Measurement Results e kx-81 hollow inclusion straingauge measured the strain value caused by stress relief(Figure 6) the stress relief curves of four points are shown inFigure 7 and the channelrsquos sequence and orientation areshown in Figure 8 e stress relief curves have three stageswith the increase of relief depth as follows initial stage straindata have no obvious changes at the beginning of the stressrelief Revulsion stage strain data have strenuous changes

400

300

200

ndash200

ndash300

ndash400

ndash500

100

ndash100

0

ndash500

ndash400

ndash300

ndash200

ndash100

0

100

200

300

400

1

12

I II

0 100

Sb ore body and number

Sample location

F3 fault

Rockburst location

Measurement point

ndash70m levelndash115m levelndash160m levelndash205m level

III

20

33

35

40 4319

9

Figure 2 No 0 exploratory grid cross section of Zhazixi Antimony Mine

Shock and Vibration 3

with the increase of relief depth Steady stage strain datatend to be stable when the stress relief positions graduallyremove from the top of strain gauge e variation rule ofmost curves is reasonable indicating that the strain gaugeworks normally and the measured data are reliable

e relationship between the stress tensor [σ] and straintensor [ε] can be expressed as follows [9]

[ε]12lowast1 [A]12lowast6

[σ]6lowast1

(1)

where A is closely related to Poissonrsquos ratio Youngrsquosmodulus and coefficients k1 k2 k3 and k4 of rock masses atmeasurement points All these parameters required forcalculation are obtained from confining pressure calibrationtests of borehole cores A special math software developed byCAGS was used to calculate the values and directions ofthree principal stresses (Table 1)

(2) In Situ Stress Field Based on the calculation results offour measurement points associated with the geologicalstructure investigation in this area in situ stress field dis-tribution characteristics of Zhazixi Antimony Mine could beeasily analyzed First of all the major principal stress (σH) isdominated by horizontal tectonic stress according to theangle between the major principal stress (σH) direction of

each measurement point and the horizontal plane is lessthan 30deg In addition the azimuth angles of major principalstress (σH) are 246degsim261deg with small amplitude of changeand the major principal stress (σH) direction of ZhazixiAntimony Mine in deep mining area is NEE-SWW Fur-thermore the principal stresses increase as the depth extendsfrom level minus75m to level minus205m Moreover the majorprincipal stress exceeds 20MPa which indicates that itbelongs to the high stress zone Combined with the shallowmeasurement results the principal stress distribution reg-ulations is as follows

σH 0026h + 4704

σv 0014h + 4006

σh 0016h + 2593

⎫⎪⎪⎬

⎪⎪⎭ (2)

where σH σv and σh represent the major principal stressintermediate principal stress and minor principal stressrespectively and h is the depth

32 Rockburst Proneness Analysis ere are many factorscausing rockbursts because of the complexity of under-ground engineeringWith respect to the influence of internalaspects rock masses should be integral and have high

Roadway

(a)

Ventilationshaft

Roadway

StopeVentilationshaft

(b)

Figure 3 Typical rockbursts (a) A spalling rockburst in a transport roadway at minus115m level (b) A strong rockburst in a ventilation shaft atminus160m level

4 Shock and Vibration

compression strength to have the ability of storing elasticstrain energy With respect to the inuence of externalfactors excavation areas should have high stresses whichengender enough elastic strain energy Rockbursts will occuronly if the two aspects are satised at the same time

Zhazixi Antimony Mine is mainly composed of sixkinds of rocks slate tupoundaceous slate quartz sandstonetupoundaceous sandstone massive stibnite and disseminatedstibnite e uniaxial compression test is as shown in Fig-ure 9 Rock mechanical properties under uniaxial com-pression are shown in Table 2

Rockburst proneness is mainly used for qualitativeanalysis of rockburst Many criteria and indexes havebeen proposed to dene and forecast rockbursts Combinedwith the eld conditions of Zhazixi Antimony Mine veevaluation indicators have been studied ssure coecientbrittleness coecient tao discriminant index impact energyindex and elastic deformation energy index respectively

Fissure coecient (Kv) reects the overall stability ofrock mass and capacity to store elastic strain energywhich has been obtained based on the number of structuralplane in the unit volume of rock mass [25] Brittlenesscoecient (B) can be presented as the ratio of uniaxial

compression strength (USC) to tensile strength (σt) whichis calculated based on physical and mechanical experi-ments (Table 2) Tao discriminant index (a) considers therelationship between the major principal stress (σ1) andUSC Impact energy index (WCF) illustrates the intensity ofenergy released after the rocks failure under uniaxialcompression loading which can be displayed by the arearatio of prepeak strength and postpeak strength according tothe complete stress-strain curves (Figure 10) Elastic energyindex (WET) manifests the elastic energy stored in rocksbefore the peak strength which is direct correlation withUSC and Youngrsquos modulus

Five rockburst proneness criteria [26] have been cal-culated on account of dipounderent test results (Table 3) Eachindex can be used to evaluate rockburst however a singleindex has large deviation due to complex geologicalstructure and lithologic distribution Five main indicatorscombined together can epoundectively improve the accuracyrate

Consequently rockbursts will occur only if all re-quirements of Equation (3) are met concurrently duringdeep mining in Zhazixi Antimony Mine Its intensity can beappraised depending on other classications

Summarize the mechanism of rockburst

Uniaxial compression tests ofdifferent samples

Uniaxial tensile tests ofdifferent samples

In-situ stressmeasurement

Field geologicalinvestigations

30 samples 30 samples

Obtain uniaxial compressive strengthcomplete stress-strain curves and related

mechanical parameters respectively

4 points

Analyze the distibutionlaw of in-situ stressin

Zhazixi antimony

Obtain number of jointsin unit volume rock

mass

Obtain tensile strengthof ore androck

Calculate rockburst proneness criteria brittlenesscoefficient (B) tao discriminant index (α) impact

energy index (WCF) and elastic energy index (WET)

Calculate fissurecoefficient(Kv)

Theory analysis

HD video of rockbreaking

Calculate the correction value ofrockburst proneness criteria in Zhazixi

antimony mine

Divide the intensity ofrockburst

Calculate the maximumprincipal stress andelastic strain energy

Rockburst events of Zhazixi antimony mine Rockburst prediction of Zhazixi antimony mine

Numerical simulation analysis

Figure 4 e block diagram of rockburst mechanism in Zhazixi Antimony Mine

Shock and Vibration 5

1 Drill a large hole with an inclination of 3 degreesand depth of 6 m using the drill pipe with a

diameter of 130mm

2 Drill a small hole with a depth of 45cm using thedrill pipe with a diameter of 38mm along the axis

at the bottom of the large hole

3 Install the KX-81 stain gauge into the small holeafter the small hole is cleaned measure the initial

strain value

4 Drilling core of small hole using hollow drill pipewith a diameter of 130mm record the strain data

once every 3cm until the core is finished

5 Measure the elastic modulus and poissonrsquos ratioof borehole cores by confining pressure

calibration tests

6 Calculate the values and directions of threeprincipal stresses through a special math softwaredeveloped by CAGS and analyze the In-situ stress

field of Zhazixi antimony mine

Figure 5 e block diagram of borehole stress relief method

Drill hole

Drill rigDrill pipe

(a)

Confining pressure calibration machine

(b)

Figure 6 Stress relief tests (a) Borehole overcoring (b) Conning pressure calibration tests

6 Shock and Vibration

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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Submit your manuscripts atwwwhindawicom

in rock masses progressively increased Once conningpressure exceeded compressive strength of rock massesthe rock masses failure mode changed into fragile failurefrom plastic failure accompanied with an instantaneousimpact failure As a result a large amount of rock masseswere ejected or thrown out due to elastic strain energyrelease (Figure 3(b)) bringing great damages to projectsefracture surface was similar to a dome

Based on previous research results many factors areconsidered to cause rockburst high geostress excavating-induced stresses the dynamic disturbance of adjacent orevein mining etc A comprehensive understanding of howdipounderent factors apoundect rockburst is essential for rockburstmechanism and prediction erefore a systematic researchhas been carried out as shown in Figure 4

3 Experimental Studies

31 In Situ Stress Measurements

311 e Measurement Method At present stress reliefmethod by overcoring is one of the in situ stress measuringmethods with high applicability and reliability [23] Itsmeasuring tools include hollow inclusion strain gaugegeological drilling rig and drill pipe of Φ130mm andΦ45mm e drill holes with dipounderent diameters (Φ130mmandΦ45mm) of measurement points separate the core fromthe surrounding rocks which relief the three dimensionalstress In the process of stress relief the core has a littleelastic deformation erefore the in situ stress could becalculated by the elastic theory after hollow inclusion strain

gauge measures the strain elastic deformation valueHowever it must be noted that the measurement pointsshould be set in the in situ stress areas of intact rockmass undisturbed by excavation Generally speaking thedepth of drilling holes should be 3ndash5 times the width of theroadway e procedure of in situ stress measurement isshown in Figure 5

e kx-81 hollow inclusion strain gauges were made byChinese Academy of Geological Sciences (CAGS) It consistsof three groups of resistance strain rosette and each group iscomposed of four strain gauges with 45deg distribution Asingle hollow inclusion strain gauge can measure the threedimensional stress state of a borehole

Considering the in situ stress has been measured inshallow part near the mine [24] four measurement pointsare layout at three levels in deep mining areas of ZhazixiAntimony Mine ie minus115m level (burial depth 560m)minus160m level (burial depth 605m) and minus205m level (burialdepth 650m) respectively

312 In Situ Stress Field Distribution

(1) Measurement Results e kx-81 hollow inclusion straingauge measured the strain value caused by stress relief(Figure 6) the stress relief curves of four points are shown inFigure 7 and the channelrsquos sequence and orientation areshown in Figure 8 e stress relief curves have three stageswith the increase of relief depth as follows initial stage straindata have no obvious changes at the beginning of the stressrelief Revulsion stage strain data have strenuous changes

400

300

200

ndash200

ndash300

ndash400

ndash500

100

ndash100

0

ndash500

ndash400

ndash300

ndash200

ndash100

0

100

200

300

400

1

12

I II

0 100

Sb ore body and number

Sample location

F3 fault

Rockburst location

Measurement point

ndash70m levelndash115m levelndash160m levelndash205m level

III

20

33

35

40 4319

9

Figure 2 No 0 exploratory grid cross section of Zhazixi Antimony Mine

Shock and Vibration 3

with the increase of relief depth Steady stage strain datatend to be stable when the stress relief positions graduallyremove from the top of strain gauge e variation rule ofmost curves is reasonable indicating that the strain gaugeworks normally and the measured data are reliable

e relationship between the stress tensor [σ] and straintensor [ε] can be expressed as follows [9]

[ε]12lowast1 [A]12lowast6

[σ]6lowast1

(1)

where A is closely related to Poissonrsquos ratio Youngrsquosmodulus and coefficients k1 k2 k3 and k4 of rock masses atmeasurement points All these parameters required forcalculation are obtained from confining pressure calibrationtests of borehole cores A special math software developed byCAGS was used to calculate the values and directions ofthree principal stresses (Table 1)

(2) In Situ Stress Field Based on the calculation results offour measurement points associated with the geologicalstructure investigation in this area in situ stress field dis-tribution characteristics of Zhazixi Antimony Mine could beeasily analyzed First of all the major principal stress (σH) isdominated by horizontal tectonic stress according to theangle between the major principal stress (σH) direction of

each measurement point and the horizontal plane is lessthan 30deg In addition the azimuth angles of major principalstress (σH) are 246degsim261deg with small amplitude of changeand the major principal stress (σH) direction of ZhazixiAntimony Mine in deep mining area is NEE-SWW Fur-thermore the principal stresses increase as the depth extendsfrom level minus75m to level minus205m Moreover the majorprincipal stress exceeds 20MPa which indicates that itbelongs to the high stress zone Combined with the shallowmeasurement results the principal stress distribution reg-ulations is as follows

σH 0026h + 4704

σv 0014h + 4006

σh 0016h + 2593

⎫⎪⎪⎬

⎪⎪⎭ (2)

where σH σv and σh represent the major principal stressintermediate principal stress and minor principal stressrespectively and h is the depth

32 Rockburst Proneness Analysis ere are many factorscausing rockbursts because of the complexity of under-ground engineeringWith respect to the influence of internalaspects rock masses should be integral and have high

Roadway

(a)

Ventilationshaft

Roadway

StopeVentilationshaft

(b)

Figure 3 Typical rockbursts (a) A spalling rockburst in a transport roadway at minus115m level (b) A strong rockburst in a ventilation shaft atminus160m level

4 Shock and Vibration

compression strength to have the ability of storing elasticstrain energy With respect to the inuence of externalfactors excavation areas should have high stresses whichengender enough elastic strain energy Rockbursts will occuronly if the two aspects are satised at the same time

Zhazixi Antimony Mine is mainly composed of sixkinds of rocks slate tupoundaceous slate quartz sandstonetupoundaceous sandstone massive stibnite and disseminatedstibnite e uniaxial compression test is as shown in Fig-ure 9 Rock mechanical properties under uniaxial com-pression are shown in Table 2

Rockburst proneness is mainly used for qualitativeanalysis of rockburst Many criteria and indexes havebeen proposed to dene and forecast rockbursts Combinedwith the eld conditions of Zhazixi Antimony Mine veevaluation indicators have been studied ssure coecientbrittleness coecient tao discriminant index impact energyindex and elastic deformation energy index respectively

Fissure coecient (Kv) reects the overall stability ofrock mass and capacity to store elastic strain energywhich has been obtained based on the number of structuralplane in the unit volume of rock mass [25] Brittlenesscoecient (B) can be presented as the ratio of uniaxial

compression strength (USC) to tensile strength (σt) whichis calculated based on physical and mechanical experi-ments (Table 2) Tao discriminant index (a) considers therelationship between the major principal stress (σ1) andUSC Impact energy index (WCF) illustrates the intensity ofenergy released after the rocks failure under uniaxialcompression loading which can be displayed by the arearatio of prepeak strength and postpeak strength according tothe complete stress-strain curves (Figure 10) Elastic energyindex (WET) manifests the elastic energy stored in rocksbefore the peak strength which is direct correlation withUSC and Youngrsquos modulus

Five rockburst proneness criteria [26] have been cal-culated on account of dipounderent test results (Table 3) Eachindex can be used to evaluate rockburst however a singleindex has large deviation due to complex geologicalstructure and lithologic distribution Five main indicatorscombined together can epoundectively improve the accuracyrate

Consequently rockbursts will occur only if all re-quirements of Equation (3) are met concurrently duringdeep mining in Zhazixi Antimony Mine Its intensity can beappraised depending on other classications

Summarize the mechanism of rockburst

Uniaxial compression tests ofdifferent samples

Uniaxial tensile tests ofdifferent samples

In-situ stressmeasurement

Field geologicalinvestigations

30 samples 30 samples

Obtain uniaxial compressive strengthcomplete stress-strain curves and related

mechanical parameters respectively

4 points

Analyze the distibutionlaw of in-situ stressin

Zhazixi antimony

Obtain number of jointsin unit volume rock

mass

Obtain tensile strengthof ore androck

Calculate rockburst proneness criteria brittlenesscoefficient (B) tao discriminant index (α) impact

energy index (WCF) and elastic energy index (WET)

Calculate fissurecoefficient(Kv)

Theory analysis

HD video of rockbreaking

Calculate the correction value ofrockburst proneness criteria in Zhazixi

antimony mine

Divide the intensity ofrockburst

Calculate the maximumprincipal stress andelastic strain energy

Rockburst events of Zhazixi antimony mine Rockburst prediction of Zhazixi antimony mine

Numerical simulation analysis

Figure 4 e block diagram of rockburst mechanism in Zhazixi Antimony Mine

Shock and Vibration 5

1 Drill a large hole with an inclination of 3 degreesand depth of 6 m using the drill pipe with a

diameter of 130mm

2 Drill a small hole with a depth of 45cm using thedrill pipe with a diameter of 38mm along the axis

at the bottom of the large hole

3 Install the KX-81 stain gauge into the small holeafter the small hole is cleaned measure the initial

strain value

4 Drilling core of small hole using hollow drill pipewith a diameter of 130mm record the strain data

once every 3cm until the core is finished

5 Measure the elastic modulus and poissonrsquos ratioof borehole cores by confining pressure

calibration tests

6 Calculate the values and directions of threeprincipal stresses through a special math softwaredeveloped by CAGS and analyze the In-situ stress

field of Zhazixi antimony mine

Figure 5 e block diagram of borehole stress relief method

Drill hole

Drill rigDrill pipe

(a)

Confining pressure calibration machine

(b)

Figure 6 Stress relief tests (a) Borehole overcoring (b) Conning pressure calibration tests

6 Shock and Vibration

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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with the increase of relief depth Steady stage strain datatend to be stable when the stress relief positions graduallyremove from the top of strain gauge e variation rule ofmost curves is reasonable indicating that the strain gaugeworks normally and the measured data are reliable

e relationship between the stress tensor [σ] and straintensor [ε] can be expressed as follows [9]

[ε]12lowast1 [A]12lowast6

[σ]6lowast1

(1)

where A is closely related to Poissonrsquos ratio Youngrsquosmodulus and coefficients k1 k2 k3 and k4 of rock masses atmeasurement points All these parameters required forcalculation are obtained from confining pressure calibrationtests of borehole cores A special math software developed byCAGS was used to calculate the values and directions ofthree principal stresses (Table 1)

(2) In Situ Stress Field Based on the calculation results offour measurement points associated with the geologicalstructure investigation in this area in situ stress field dis-tribution characteristics of Zhazixi Antimony Mine could beeasily analyzed First of all the major principal stress (σH) isdominated by horizontal tectonic stress according to theangle between the major principal stress (σH) direction of

each measurement point and the horizontal plane is lessthan 30deg In addition the azimuth angles of major principalstress (σH) are 246degsim261deg with small amplitude of changeand the major principal stress (σH) direction of ZhazixiAntimony Mine in deep mining area is NEE-SWW Fur-thermore the principal stresses increase as the depth extendsfrom level minus75m to level minus205m Moreover the majorprincipal stress exceeds 20MPa which indicates that itbelongs to the high stress zone Combined with the shallowmeasurement results the principal stress distribution reg-ulations is as follows

σH 0026h + 4704

σv 0014h + 4006

σh 0016h + 2593

⎫⎪⎪⎬

⎪⎪⎭ (2)

where σH σv and σh represent the major principal stressintermediate principal stress and minor principal stressrespectively and h is the depth

32 Rockburst Proneness Analysis ere are many factorscausing rockbursts because of the complexity of under-ground engineeringWith respect to the influence of internalaspects rock masses should be integral and have high

Roadway

(a)

Ventilationshaft

Roadway

StopeVentilationshaft

(b)

Figure 3 Typical rockbursts (a) A spalling rockburst in a transport roadway at minus115m level (b) A strong rockburst in a ventilation shaft atminus160m level

4 Shock and Vibration

compression strength to have the ability of storing elasticstrain energy With respect to the inuence of externalfactors excavation areas should have high stresses whichengender enough elastic strain energy Rockbursts will occuronly if the two aspects are satised at the same time

Zhazixi Antimony Mine is mainly composed of sixkinds of rocks slate tupoundaceous slate quartz sandstonetupoundaceous sandstone massive stibnite and disseminatedstibnite e uniaxial compression test is as shown in Fig-ure 9 Rock mechanical properties under uniaxial com-pression are shown in Table 2

Rockburst proneness is mainly used for qualitativeanalysis of rockburst Many criteria and indexes havebeen proposed to dene and forecast rockbursts Combinedwith the eld conditions of Zhazixi Antimony Mine veevaluation indicators have been studied ssure coecientbrittleness coecient tao discriminant index impact energyindex and elastic deformation energy index respectively

Fissure coecient (Kv) reects the overall stability ofrock mass and capacity to store elastic strain energywhich has been obtained based on the number of structuralplane in the unit volume of rock mass [25] Brittlenesscoecient (B) can be presented as the ratio of uniaxial

compression strength (USC) to tensile strength (σt) whichis calculated based on physical and mechanical experi-ments (Table 2) Tao discriminant index (a) considers therelationship between the major principal stress (σ1) andUSC Impact energy index (WCF) illustrates the intensity ofenergy released after the rocks failure under uniaxialcompression loading which can be displayed by the arearatio of prepeak strength and postpeak strength according tothe complete stress-strain curves (Figure 10) Elastic energyindex (WET) manifests the elastic energy stored in rocksbefore the peak strength which is direct correlation withUSC and Youngrsquos modulus

Five rockburst proneness criteria [26] have been cal-culated on account of dipounderent test results (Table 3) Eachindex can be used to evaluate rockburst however a singleindex has large deviation due to complex geologicalstructure and lithologic distribution Five main indicatorscombined together can epoundectively improve the accuracyrate

Consequently rockbursts will occur only if all re-quirements of Equation (3) are met concurrently duringdeep mining in Zhazixi Antimony Mine Its intensity can beappraised depending on other classications

Summarize the mechanism of rockburst

Uniaxial compression tests ofdifferent samples

Uniaxial tensile tests ofdifferent samples

In-situ stressmeasurement

Field geologicalinvestigations

30 samples 30 samples

Obtain uniaxial compressive strengthcomplete stress-strain curves and related

mechanical parameters respectively

4 points

Analyze the distibutionlaw of in-situ stressin

Zhazixi antimony

Obtain number of jointsin unit volume rock

mass

Obtain tensile strengthof ore androck

Calculate rockburst proneness criteria brittlenesscoefficient (B) tao discriminant index (α) impact

energy index (WCF) and elastic energy index (WET)

Calculate fissurecoefficient(Kv)

Theory analysis

HD video of rockbreaking

Calculate the correction value ofrockburst proneness criteria in Zhazixi

antimony mine

Divide the intensity ofrockburst

Calculate the maximumprincipal stress andelastic strain energy

Rockburst events of Zhazixi antimony mine Rockburst prediction of Zhazixi antimony mine

Numerical simulation analysis

Figure 4 e block diagram of rockburst mechanism in Zhazixi Antimony Mine

Shock and Vibration 5

1 Drill a large hole with an inclination of 3 degreesand depth of 6 m using the drill pipe with a

diameter of 130mm

2 Drill a small hole with a depth of 45cm using thedrill pipe with a diameter of 38mm along the axis

at the bottom of the large hole

3 Install the KX-81 stain gauge into the small holeafter the small hole is cleaned measure the initial

strain value

4 Drilling core of small hole using hollow drill pipewith a diameter of 130mm record the strain data

once every 3cm until the core is finished

5 Measure the elastic modulus and poissonrsquos ratioof borehole cores by confining pressure

calibration tests

6 Calculate the values and directions of threeprincipal stresses through a special math softwaredeveloped by CAGS and analyze the In-situ stress

field of Zhazixi antimony mine

Figure 5 e block diagram of borehole stress relief method

Drill hole

Drill rigDrill pipe

(a)

Confining pressure calibration machine

(b)

Figure 6 Stress relief tests (a) Borehole overcoring (b) Conning pressure calibration tests

6 Shock and Vibration

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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compression strength to have the ability of storing elasticstrain energy With respect to the inuence of externalfactors excavation areas should have high stresses whichengender enough elastic strain energy Rockbursts will occuronly if the two aspects are satised at the same time

Zhazixi Antimony Mine is mainly composed of sixkinds of rocks slate tupoundaceous slate quartz sandstonetupoundaceous sandstone massive stibnite and disseminatedstibnite e uniaxial compression test is as shown in Fig-ure 9 Rock mechanical properties under uniaxial com-pression are shown in Table 2

Rockburst proneness is mainly used for qualitativeanalysis of rockburst Many criteria and indexes havebeen proposed to dene and forecast rockbursts Combinedwith the eld conditions of Zhazixi Antimony Mine veevaluation indicators have been studied ssure coecientbrittleness coecient tao discriminant index impact energyindex and elastic deformation energy index respectively

Fissure coecient (Kv) reects the overall stability ofrock mass and capacity to store elastic strain energywhich has been obtained based on the number of structuralplane in the unit volume of rock mass [25] Brittlenesscoecient (B) can be presented as the ratio of uniaxial

compression strength (USC) to tensile strength (σt) whichis calculated based on physical and mechanical experi-ments (Table 2) Tao discriminant index (a) considers therelationship between the major principal stress (σ1) andUSC Impact energy index (WCF) illustrates the intensity ofenergy released after the rocks failure under uniaxialcompression loading which can be displayed by the arearatio of prepeak strength and postpeak strength according tothe complete stress-strain curves (Figure 10) Elastic energyindex (WET) manifests the elastic energy stored in rocksbefore the peak strength which is direct correlation withUSC and Youngrsquos modulus

Five rockburst proneness criteria [26] have been cal-culated on account of dipounderent test results (Table 3) Eachindex can be used to evaluate rockburst however a singleindex has large deviation due to complex geologicalstructure and lithologic distribution Five main indicatorscombined together can epoundectively improve the accuracyrate

Consequently rockbursts will occur only if all re-quirements of Equation (3) are met concurrently duringdeep mining in Zhazixi Antimony Mine Its intensity can beappraised depending on other classications

Summarize the mechanism of rockburst

Uniaxial compression tests ofdifferent samples

Uniaxial tensile tests ofdifferent samples

In-situ stressmeasurement

Field geologicalinvestigations

30 samples 30 samples

Obtain uniaxial compressive strengthcomplete stress-strain curves and related

mechanical parameters respectively

4 points

Analyze the distibutionlaw of in-situ stressin

Zhazixi antimony

Obtain number of jointsin unit volume rock

mass

Obtain tensile strengthof ore androck

Calculate rockburst proneness criteria brittlenesscoefficient (B) tao discriminant index (α) impact

energy index (WCF) and elastic energy index (WET)

Calculate fissurecoefficient(Kv)

Theory analysis

HD video of rockbreaking

Calculate the correction value ofrockburst proneness criteria in Zhazixi

antimony mine

Divide the intensity ofrockburst

Calculate the maximumprincipal stress andelastic strain energy

Rockburst events of Zhazixi antimony mine Rockburst prediction of Zhazixi antimony mine

Numerical simulation analysis

Figure 4 e block diagram of rockburst mechanism in Zhazixi Antimony Mine

Shock and Vibration 5

1 Drill a large hole with an inclination of 3 degreesand depth of 6 m using the drill pipe with a

diameter of 130mm

2 Drill a small hole with a depth of 45cm using thedrill pipe with a diameter of 38mm along the axis

at the bottom of the large hole

3 Install the KX-81 stain gauge into the small holeafter the small hole is cleaned measure the initial

strain value

4 Drilling core of small hole using hollow drill pipewith a diameter of 130mm record the strain data

once every 3cm until the core is finished

5 Measure the elastic modulus and poissonrsquos ratioof borehole cores by confining pressure

calibration tests

6 Calculate the values and directions of threeprincipal stresses through a special math softwaredeveloped by CAGS and analyze the In-situ stress

field of Zhazixi antimony mine

Figure 5 e block diagram of borehole stress relief method

Drill hole

Drill rigDrill pipe

(a)

Confining pressure calibration machine

(b)

Figure 6 Stress relief tests (a) Borehole overcoring (b) Conning pressure calibration tests

6 Shock and Vibration

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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Submit your manuscripts atwwwhindawicom

1 Drill a large hole with an inclination of 3 degreesand depth of 6 m using the drill pipe with a

diameter of 130mm

2 Drill a small hole with a depth of 45cm using thedrill pipe with a diameter of 38mm along the axis

at the bottom of the large hole

3 Install the KX-81 stain gauge into the small holeafter the small hole is cleaned measure the initial

strain value

4 Drilling core of small hole using hollow drill pipewith a diameter of 130mm record the strain data

once every 3cm until the core is finished

5 Measure the elastic modulus and poissonrsquos ratioof borehole cores by confining pressure

calibration tests

6 Calculate the values and directions of threeprincipal stresses through a special math softwaredeveloped by CAGS and analyze the In-situ stress

field of Zhazixi antimony mine

Figure 5 e block diagram of borehole stress relief method

Drill hole

Drill rigDrill pipe

(a)

Confining pressure calibration machine

(b)

Figure 6 Stress relief tests (a) Borehole overcoring (b) Conning pressure calibration tests

6 Shock and Vibration

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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Submit your manuscripts atwwwhindawicom

Kv gt 055

Blt 40

αlt 114

WCF gt 1

WET gt 100

(3)

From Equation (3) rockburst proneness criteria of ZhazixiAntimony Mine have been presented which reveal the internalrequirement of rockburst in Zhazixi antimony However theexternal factors should be satised at the same time that is the

rock mass must be in the high stress area where the rock masscan store a larger elastic strain energy As long as the internalfactors and external factors are met rockbursts can be accu-rately predicted in Zhazixi Antimony Mine

4 Numerical Simulation Analysis

41 eory Analysis Rock masses keep stress equilibriumstate before excavation and they are apoundected by in situ stress(Fi) Once rock masses are excavated stresses will beredistributed In addition to the original stress the

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

04080

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(a)

0 3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

0

8040

120160200240280320360400

Stra

in (μ

ε)

Channels1234

5678

9101112

(b)

Length of stress relief (cm)0 3 6 9 12 15 18 21 24 27 30 33 36 39

400360320280240200160120

80

ndash80

40

ndash400

Stra

in (μ

ε)

Channels1234

5678

9101112

(c)

0

0

3 6 9 12 15 18 21 24 27 30 33 36 39Length of stress relief (cm)

ndash80ndash40

4080

120160200240280320360400440480520

Stra

in (μ

ε)

Channels1234

5678

9101112

(d)

Figure 7 e stress relief curves (a) Point 1 (b) Point 2 (c) Point 3 (d) Point 4

Shock and Vibration 7

surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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surrounding rocks are apoundected by the disturbance stress ofthe mining (Ti

ν) which keeps the rock masses being in static

equilibrium under the action of specied body and surfaceforces (Figure 11)

After the rock masses are disturbed the stored strainenergy inside the rock can be embodied through the virtualwork done by the body force Fi per unit volume and thesurface force Ti

νper unit area [27]

Table 1 Measurement results of principal stress at four points of Zhazixi Antimony Mine

No Level (m)e major principal stress (σH) e intermediate principal stress (σv) e minor principal stress (σh)

Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg) Value (MPa) Orientation (deg) Dip (deg)1 minus115 1636 25731 325 800 34649 16594 736 18003 104442 minus160 1961 24651 16695 986 32136 4861 927 16719 38643 minus160 1876 26083 16527 1279 30692 6924 1043 17467 14304 minus205 2132 8045 11216 1407 13028 5947 1192 14928 2185

Strain gauge cable

Sealing ring

Cavities and adhesives

Retaining pin

Gum exudation hole

Directional pin

Epoxy resin tube

Resistance strain rosette

Piston rod

Guide rod

A

A

(a)

Y Z

X

θ

A B C

11

10

9

12

6

7

5

8

23

1

4

AB

C

θ

120

120

120deg

4545

45

(b)

Figure 8 Hollow inclusion strain gauge

(a)

Computerterminal

Controlcabinet

Loadingdirection

HD videocamera

Loadingdirection

(b)

(c)

Figure 9 e experimental setup (a) Universal hydraulic testing machine (b) e experimental system (c) Six kinds of rock samples

8 Shock and Vibration

W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

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W 1113946V

Fiδui dv + 1113946STv

iδui dS (4)

On substituting Tv

i σijvij in accordance with Lamersquosstress ellipsoid we have

1113946STi

v

δui dS 1113946Sσijδuivj dS 1113946

Vσijδui1113872 1113873

jdv

1113946Vσijjδuj dv + 1113946

Vσijδuij dv

(5)

According to the equation of equilibrium the first integralon the right-hand side is equal to minus1113938 Fiδui dv On account ofthe symmetry of σij the second integral can be written as

1113946Vσij

12

δuij + δuji1113872 11138731113876 1113877dv 1113946Vσijδeij dv (6)

erefore (6) becomes

W 1113946V

Fiδui dv + 1113946STi

v

δui dS 1113946Vσijδeij dv

12σijeij

(7)

Substituting the generalized Hookersquos law into the aboveequation Equation (7) can be described by stresses tensor asfollows

W 12E

(1 + μ)σijσji minus μI1113960 1113961

I 11139443

i1σij

(8)

As for the surrounding rock near a tunnel or cavity thestresses state are always presented as tangential stress σ1radial stress σ2 and axial stress σ3en the W is rewritten as

U 12E

σ21 + σ22 + σ23 minus 2] σ1σ2 + σ2σ3 + σ3σ1( 11138571113960 1113961 (9)

42 Numerical Calculation Model Zhazixi Antimony Minehas been mined using shrinkage stoping method over 110years since 1906 and the mining sequences are chaotic andstress distribution is complex because the rich ore veins arepreferential mined Especially adjacent veins are too close tointerrelate in mining process At present no 1 no 9 and no19 are continuously mined To analyze stress and energycharacteristics of steeply inclined thin veins five adjacentveins of group I in Zhazixi Antimony Mine are regarded asstudy objective According to the mining situation thenumerical model was built from level minus25m to level minus205m

by FLAC3D with the dimension of 300m (length) times 200m(width) times 300m (height) (Figure 12) In the coordinatesystem of the model the positive direction of Y-axis and X-axis is northwest 25deg and northeast 65deg respectively ephysical and mechanical parameters of rocks are shown inTable 2

Considering the height of overlying strata is 420m ontop of the model self-weight stress calculated by Equation(10) is applied as follows

σz chz 275 times 420 1155MPa (10)

where c and hv are the unit weight of the rock mass and theheight of the overlying strata respectively

Based on Equation (2) the X axis and Y axis of the modelare applied maximum principal stress and minimumprincipal stress respectively

According to mining status four mining sequences havebeen discussed (1) mining from hanging wall to footwall (2)advanced one-level mining (3) advanced two-level miningand (4) mining along the inclined direction Two rows ofmonitoring lines are arranged on the hanging wall of the 3vein (Figure 12(b))

43 Strain Energy Evolution during Steeply Inclined 1inVeins Mining As demonstrated in Figure 13 a largerpressure relief area with a diameter of 20m is formed in thefootwall of ore vein which keeps the ore veins of next level tostay in low stress areas by sequence 1 While there is anellipsoidal pressure relief arch between two adjacent oreveins by sequence 2 it can induce concentrated stress ofadjacent veins and make self-weight stress transmit to ad-vanced veins corner along the stress arch which causes stressincrease rapidly Obviously the greater the depth of advancemining along the inclined direction of an ore vein thegreater the stress concentration factor at the bottom cornerof hanging wall

Accordingly the maximum stress concentration factor ofsequence 1 near the boundary is only 085 based on mon-itoring results and the maximum stress concentration fac-tors of sequence 2 sequence 3 and sequence 4 near theboundary are 125 137 and 152 respectively (Figure 14(a))Furthermore the stress concentration occurs in the range of10 m near bottom corner of the stope where rockburstsappear easily At the same time the transverse influenceradius of stress concentration area at the bottom of stope isless than 5m that is the maximum stresses of monitoringline 2 are close to in situ stress (Figure 14(b))

Table 2 Physical and mechanical properties of rocks

Lithology Density(gcm3)

UCS(MPa)

Tensile strength(Mpa) Poisson ratio Cohesion

(MPa)Youngrsquos modulus

(GPa)Internal friction

angle (deg)Slate 281 7111 429 023 9 1723 3648Tuffaceous slate 290 8246 591 032 1003 2532 4023Quartz sandstone 275 6517 745 020 1732 2365 4532Tuffaceous sandstone 270 7612 606 026 1121 3595 4194Massive stibnite 384 11434 457 021 1184 5823 4980Disseminated stibnite 312 9315 554 025 986 4312 5061

Shock and Vibration 9

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

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wwwhindawicom Volume 2018

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Submit your manuscripts atwwwhindawicom

Considering elastic strain energy (Figure 15) androckburst proneness criteria (Equation (3)) comprehen-sively the maximum stress and elastic strain energy oftenappear in the corner of the hanging wall Accordingly the

main reasons for different types of rockburst are attributedto mining sequences To understand the rockburst mecha-nisms Figure 15(a) presents the maximum elastic strainenergy evolution curves on the corner of each level By

00 02 04 06 08 10 12 14 16 180

10

20

30

40

50

σ c (M

Pa)

ε (times10ndash2)

(a)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

(b)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

(c)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

(d)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0102030405060708090

100110

(e)

σ c (M

Pa)

ε (times10ndash2)00 02 04 06 08 10 12 14 16 18

0

10

20

30

40

50

60

70

80

90

(f )

Figure 10 Strain-stress curves of rock masses in Zhazixi Antimony Mine (a) Slate (b) Tuffaceous slate (c) Quartz sandstone(d) Tuffaceous sandstone (e) Dense massive stibnite (f ) Disseminated stibnite

10 Shock and Vibration

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

companion it has been found that mining sequence 1 willhave no rockbursts and rockbursts may occur at miningsequence 2 mining sequence 3 and mining sequence 4 andthe intensity of rockburst increases with mining depth edeeper the advanced mining level is the greater the storedelastic strain energy is

Combined with the process of rock dynamic failureunder uniaxial compression test there may be spalling typeof rockburst when the elastic strain energy is less than200 kJmiddotmminus3 however when the elastic strain energy exceeds300 kJmiddotmminus3 throwing-type of rockburst most likely occursEspecially the storage elastic strain energy is large enoughwhenmining level surpasses level minus115m which leads to thestrong rockburst accompanied with ejecting or throwing inthe mining face rstly As shown in Figure 15(b) the elasticstrain energy stored in rock masses far away from mining

face 5 m are less than 200 kJmiddotmminus3 and they might producespalling type of rockburst Based on the superposition epoundectof elastic strain energy it produces a large scale of strongrockburst

5 Rockburst Validation

Based on statistics data there were 30 rockburst eventsbetween May 2012 and May 2013 in Zhazixi AntimonyMine During this period a prospecting tunnel ore vein wasexcavated at minus115m level three stopes ore vein was mined atminus160m level a main haulage roadway was excavated andtwo stopes were cut at minus205m level e evolution mech-anism of rockburst can be summarized as follows

Rockburst began to appear when mining depth reachedminus115m level where the elastic strain energy exceeded

Table 3 Rockburst proneness criteria

Criterion Formula Empirical value Correction value Rockburst intensity

Fissure coecient (Kv) Kv f(Jv)gt08 gt075 Strong

06sim08 065sim075 Moderate055sim060 055sim075 Weak

Brittleness coecient (B) B σcσtlt145 lt168 Strong

145sim267 168sim25 Moderate267sim40 25sim40 Weak

Tao discriminant index (α) a σcσ1le25 le4 Strong

25sim55 4sim63 Moderate55sim145 63sim114 Weak

Impact energy index (WCF) WCF WEWP

gt3 gt3 Strong2sim3 17sim28 Moderate1sim2 1sim17 Weak

Elastic energy index (WET) WET σ2c2ES

gt200 gt300 Strong100sim200 200sim300 Moderate50sim100 100sim200 Weak

Mined-out area

Mined-out area O

re piller

Ore vein

Ore vein

Fi

Tv

i

Vi

θ

(a) (b)

Figure 11 e stress state of steeply inclined thin veins (a) Stress vector (b) eoretical stress model

Shock and Vibration 11

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

SIG1 (Pa)

ndash7E + 06ndash8E + 06ndash9E + 06ndash1E + 07ndash11E + 07ndash12E + 07ndash13E + 07ndash14E + 07ndash15E + 07ndash16E + 07ndash17E + 07ndash18E + 07ndash19E + 07ndash2E + 07ndash21E + 07ndash22E + 07ndash23E + 07

(a)

SIG1 (Pa)

ndash4E + 06

ndash6E + 06

ndash8E + 06

ndash1E + 07

ndash12E + 07

ndash14E + 07

ndash16E + 07

ndash18E + 07

ndash2E + 07

ndash22E + 07

ndash24E + 07

ndash26E + 07

ndash28E + 07

ndash3E + 07

ndash32E + 07

(b)

Figure 13 Continued

51 2 3 4 Ore veinOre pillar

Levelndash25mLevelndash70mLevel

ndash115mLevel

ndash160mLevel

ndash205m

X

Z

P

10m 25m

P225m

5m40

m

70deg

5m5m

40m

1m5m

10m

10m

Line 1 Line 2

(a) (b)

Figure 12 (a) Numerical calculation model and (b) monitoring points layout

12 Shock and Vibration

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

100 kJmiddotmminus3 according to the numerical results When miningto minus160m mining activities caused local stress concentra-tion where elastic strain energy exceeds 350 kJmiddotmminus3 resultingin frequent occurrence of dipounderent types of rockburst asshown in Figure 16(a)

Rockburst intensity is closely related to rock mechanicalproperties (Figure 16(b)) Especially slate is prone tospalling rockburst with poor capacity of stored elastic strainenergy because of the smooth internal structural plane butmassive stibnite could withstand great pressure and accu-mulate great elastic strain energy due to good integrityhence they generally occur strong rockburst in the highstress area

According to the characteristics of shallow-holeshrinkage stoping stopes and ventilation shafts are gener-ally arranged along the ore veins so they often appear high-intensity rockbursts because of the special physical andmechanical properties of stibnite

Above all it is epoundective to predict rockburst combinedwith rockburst proneness criteria and numerical stimulationanalysis in Zhazixi Antimony Mine

6 Conclusions

(1) Stress relief method by overcoring is utilized to obtainin situ stress of four measurement points in Zhazixi

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash2055

10

15

20

25

30

35

Monitoring point depth (m)

σ 1 (M

Pa)

(a)

Sequence 1Sequence 2

Sequence 3Sequence 4

Monitoring point depth (m)ndash25 ndash70 ndash115 ndash160 ndash205

5

10

15

20

30

25

σ 1 (M

Pa)

(b)

Figure 14 e maximum principal stress values evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash35E + 07

(c)

SIG1 (Pa)

ndash6E + 06ndash8E + 06ndash1E + 07ndash12E + 07ndash14E + 07ndash16E + 07ndash18E + 07ndash2E + 07ndash22E + 07ndash24E + 07ndash26E + 07ndash28E + 07ndash3E + 07ndash32E + 07ndash34E + 07ndash36E + 07ndash38E + 07

(d)

Figure 13 e principal stress nephogram (a) Sequence 1 (b) Sequence 2 (c) Sequence 3 (d) Sequence 4

Shock and Vibration 13

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

ndash115m level ndash160m level ndash205m level

SED (KJmndash3)100ndash200201ndash300301ndash400

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

(a)

ndash115m level ndash160m level ndash205m level

201305201302201211201208201205Date (yearmonth)

Throw out

Ejection

SpallingRock

burs

t typ

e

Tuffaceous sandstoneDisseminated stibniteMassive stibnite

SlateTuffaceous slateQuartz sandstone

Lithology

(b)

Figure 16 Continued

450St

rain

ener

gy d

ensit

y (k

Jmndash3

)

400

350

300

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(a)

Stra

in en

ergy

den

sity

(kJm

ndash3)

250

200

150

100

50

0

Sequence 1Sequence 2

Sequence 3Sequence 4

ndash25 ndash70 ndash115 ndash160 ndash205Monitoring point depth (m)

(b)

Figure 15 e maximum elastic strain energy evolution with depth (a) Monitoring line 1 (b) Monitoring line 2

14 Shock and Vibration

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

antimony e in situ measurement results show thatthe major principal stress exceeds 20MPa with theNEE-SWW direction in deep mining areas Further-more the principal stress distribution regulations inZhazixi Antimony Mine are summed up

(2) With respect to the influence of lithology uniaxialcompression tests are carried out towards six kindsof rocks Combined with field geological survey andin situ measurements in Zhazixi Antimony Minefive criteria of rockburst proneness are corrected toqualitative analyzed rockburst conditions Conse-quently rockburst proneness criteria of ZhazixiAntimony Mine are put forward

(3) According to the distribution characteristics of steeplyinclined thin veins the stress and elastic strain energyevolution are analyzed by numerical simulation infour mining sequences e results reveal advancedmining is themain factor to energy accumulationedeeper the advanced mining is the greater the storedelastic strain energy is Enough elastic strain energycan also induce deep elastic strain energy release tocause chain reaction of large-scale rockbursts

(4) Comparing rockburst events with prediction resultsthe unanimous conclusions have been drawnthrowing-type rockbursts frequently occur in massivestibnite of ventilation shaft and stope where the elasticstrain energy exceeds 300 kJmiddotmminus3 due to the influenceof mining sequence spalling-type rockbursts gener-ally appear in slate of roadway where the elastic strainenergy exceeds 100 kJmiddotmminus3 under high stress state andejection-type rockbursts arise in different rock massesunder a certain condition

Data Availability

e data used to support the findings of this study are in-cluded within the article

Conflicts of Interest

e authors declare that there are no conflicts of interestregarding the publication of this paper

References

[1] T B Li C C Ma M L Zhu L B Meng and G Q ChenldquoGeomechanical types and mechanical analyses of rock-burstsrdquo Engineering Geology vol 222 no 3 pp 72ndash83 2017

[2] X T Feng Y Yu G L Feng Y-X Xiao B-R Chen andQ Jiang ldquoFractal behaviour of the microseismic energy as-sociated with immediate rockbursts in deep hard rock tun-nelsrdquo Tunnelling and Underground Space Technology vol 51no 1 pp 98ndash107 2016

[3] J M Wang X H Zeng and J F Zhou ldquoPractices onrockburst prevention and control in headrace tunnels ofJinping II hydropower stationrdquo Journal of Rock Mechanicsand Geotechnical Engineering vol 4 no 3 pp 258ndash268 2012

[4] J P Yang W Z Chen W S Zhao et al ldquoGeohazards oftunnel excavation in interbedded layers under high in situstressrdquo Engineering Geology vol 230 no 9 pp 11ndash22 2017

[5] X X Liu S B Zhan Y B Zhang X Wang Z Liang andB Tian ldquoemechanical and fracturing of rockburst in tunneland its acoustic emission characteristicsrdquo Shock and Vibra-tion vol 2018 Article ID 3503940 11 pages 2018

[6] M F Cai ldquoPrediction and prevention of rockburst in metalmines-a case study of Sanshandao gold minerdquo Journal of RockMechanics and Geotechnical Engineering vol 8 no 2pp 204ndash211 2016

[7] X Y Feng J P Liu B R Chen Y Xiao G Feng andF Zhang ldquoMonitoring warning and control of rockburst indeep metal minesrdquo Engineering vol 3 no 4 pp 538ndash5452017

[8] W Lei L Q Huang A Taheri and X Li ldquoRockburstcharacteristics and numerical simulation based on a strainenergy density index a case study of a roadway in Linglonggold mine Chinardquo Tunnelling and Underground SpaceTechnology vol 69 pp 223ndash232 2017

[9] S Afraei K Shahriar and S H Madani ldquoStatistical assess-ment of rock burst potential and contributions of considered

201205 201208 201211 201302 201305Date (yearmonth)

Ejection

SpallingRock

burs

t typ

eThrow out

ndash115m level ndash160m level ndash205m level

LocationVentilation shaft

Stope

Roadway

(c)

Figure 16 Verification of rockburst events between May 2012 and May 2013 (a) Rockburst type and strain elastic energy (b) Rockbursttype and lithology (c) Rockburst type and location

Shock and Vibration 15

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

predictor variables in the taskrdquo Tunnelling and UndergroundSpace Technology vol 72 pp 250ndash271 2018

[10] S J Li X T Feng Z H Li B Chen C Zhang and H ZhouldquoIn situ monitoring of rockburst nucleation and evolution inthe deeply buried tunnels of Jinping II hydropower stationrdquoEngineering Geology vol 137-138 no 7 pp 85ndash96 2012

[11] S J Miao M F Cai Q F Guo and Z J Huang ldquoRock burstprediction based on in-situ stress and energy accumulationtheoryrdquo International Journal of Rock Mechanics and MiningSciences vol 83 no 2 pp 86ndash94 2016

[12] G S Su Y J Shi X T Feng J Jiang J Zhang and Q JiangldquoTrue-triaxial experimental study of the evolutionary featuresof the acoustic emissions and sounds of rockburst processrdquoRock Mechanics and Rock Engineering vol 51 no 2pp 375ndash389 2018

[13] F Z Meng H Zhou Z Q Wang et al ldquoExperimental studyon the prediction of rockburst hazards induced by dynamicstructural plane shearing in deeply buried hard rock tunnelsrdquoInternational Journal of Rock Mechanics and Mining Sciencesvol 86 no 2 pp 210ndash223 2016

[14] Q J Zhu Y Feng M Cai J H Liu and H H WangldquoInterpretation of the extent of hydraulic fracturing forrockburst prevention using microseismic monitoring datardquoJournal of Natural Gas Science and Engineering vol 38 no 6pp 107ndash119 2017

[15] Q Y Zhang X T Zhang Z C Wang W Xiang and J XueldquoFailure mechanism and numerical simulation of zonal dis-integration around a deep tunnel under high stressrdquo In-ternational Journal of Rock Mechanics and Mining Sciencesvol 93 pp 344ndash355 2017

[16] W C Zhu Z H Li L Zhu and C A Tang ldquoNumericalsimulation on rockburst of underground opening triggered bydynamic disturbancerdquo Tunnelling and Underground SpaceTechnology vol 25 no 5 pp 587ndash599 2010

[17] L S Jiang P Wang P P Zhang P Q Zheng and B XuldquoNumerical analysis of the effects induced by normal faultsand dip angles on rock burstsrdquo Comptes Rendus Mecaniquevol 345 no 10 pp 690ndash705 2017

[18] L Driad-Lebeau F Lahaie M Al Heib J P Josien P Bigarreand J F Noirel ldquoSeismic and geotechnical investigationsfollowing a rockburst in a complex French mining districtrdquoInternational Journal of Coal Geology vol 64 no 1-2pp 66ndash78 2005

[19] X P Zhou Q H Qian and H Q Yang ldquoRock burst of deepcircular tunnels surrounded by weakened rock mass withcracksrdquo 1eoretical and Applied Fracture Mechanics vol 56no 2 pp 79ndash88 2011

[20] K Holub and V Petros ldquoSome parameters of rockburstsderived from underground seismological measurementsrdquoTectonophysics vol 456 no 1-2 pp 67ndash73 2008

[21] C P Lu Y Liu N Zhang T-B Zhao and H-Y Wang ldquoIn-situ and experimental investigation of rockburst precursorand prevention induced by fault sliprdquo International Journal ofRock Mechanics and Mining Sciences vol 108 pp 86ndash952018

[22] F ZMeng H Zhou Z QWang et al ldquoExperimental study offactors affecting fault slip rockbursts in deeply buried hardrock tunnelsrdquo Bulletin of Engineering geology and the envi-ronment vol 76 no 3 pp 1167ndash1182 2017

[23] S Zhong Q Jiang X T Feng et al ldquoA case of in-situ stressmeasurement in Chinese Jingping underground laboratoryrdquoRock and Soil Mechanics vol 39 no 1 pp 356ndash366 2018

[24] G Y Zhu X H Guo W Z Chen et al ldquoInversion of in-situstress and its application in Xuefengshan roadway tunnelrdquo

Central South Highway Engineering vol 31 no 1 pp 71ndash752006 in Chinese

[25] S W Duan and X E Xu ldquoDiscussion of problems in cal-culation and application of rock mass integrity coefficientrdquoJournal of Engineering Geology vol 21 no 4 pp 548ndash5522013 in Chinese

[26] J A Wang and H D Park ldquoComprehensive prediction ofrockburst based on analysis strain energy in rocksrdquo Tunnellingand Underground Space Technology vol 16 no 1 pp 49ndash572001

[27] Y C Fung Foundations of Solid Mechanics Prentice-HallUpper Saddle River NJ USA 1977

16 Shock and Vibration

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom

International Journal of

AerospaceEngineeringHindawiwwwhindawicom Volume 2018

RoboticsJournal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Active and Passive Electronic Components

VLSI Design

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Shock and Vibration

Hindawiwwwhindawicom Volume 2018

Civil EngineeringAdvances in

Acoustics and VibrationAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Electrical and Computer Engineering

Journal of

Advances inOptoElectronics

Hindawiwwwhindawicom

Volume 2018

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

Control Scienceand Engineering

Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom

Journal ofEngineeringVolume 2018

SensorsJournal of

Hindawiwwwhindawicom Volume 2018

International Journal of

RotatingMachinery

Hindawiwwwhindawicom Volume 2018

Modelling ampSimulationin EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Chemical EngineeringInternational Journal of Antennas and

Propagation

International Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Navigation and Observation

International Journal of

Hindawi

wwwhindawicom Volume 2018

Advances in

Multimedia

Submit your manuscripts atwwwhindawicom