Research Article Parameters Optimization of Curtain

Research ArticleParameters Optimization of Curtain Grouting ReinforcementCycle in Yonglian Tunnel and Its Application

Qingsong Zhang, Peng Li, Gang Wang, Shucai Li, Xiao Zhang, Qianqing Zhang,Qian Wang, and Jianguo Liu

Geotechnical and Structural Engineering Research Center, Shandong University, Jinan, Shandong 250061, China

Correspondence should be addressed to Peng Li; [email protected]

Received 26 December 2014; Revised 9 February 2015; Accepted 12 February 2015

Academic Editor: Zdenek Kala

Copyright © 2015 Qingsong Zhang et al. This 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 is properlycited.

For practical purposes, the curtain grouting method is an effective method to treat geological disasters and can be used to improvethe strength and permeability resistance of surrounding rock. Selection of the optimal parameters of grouting reinforcement cycleespecially reinforcement cycle thickness is one of the most interesting areas of research in curtain grouting designs. Based onthe fluid-structure interaction theory and orthogonal analysis method, the influence of reinforcement cycle thickness, elasticmodulus, and permeability on water inflow of tunnel after grouting and stability of surrounding rock was analyzed. As to thewater inflow of tunnel after grouting used as performance evaluation index of grouting reinforcement cycle, it can be concludedthat the permeability was the most important factor followed by reinforcement cycle thickness and elastic modulus. Furthermore,pore water pressure field, stress field, and plastic zone of surrounding rock were calculated by using COMSOL software underdifferent conditions of reinforcement cycle thickness. It also can be concluded that the optimal thickness of reinforcement cycleand permeability can be adopted as 8m and 1/100 of the surrounding rock permeability in the curtain grouting reinforcement cycle.The engineering case provides a reference for similar engineering.

1. Introduction

With the rapid development of highways, more and moretunnels are to be constructed in China. Unfavorable geologysuch as fault and karst which is easy to induce geological dis-asters is often exposed by excavation during the constructionof tunnels. Casualties and economic loss caused by geologicaldisasters are very serious at present [1–3].

For practical purposes, curtain grouting method is aneffective method to manage geological disasters and can beused to improve the strength and permeability resistance ofsurrounding rock [4]. Related to the economy and safety,selection of the optimal parameters of grouting reinforce-ment cycle especially thickness of reinforcement cycle is oneof the most interesting areas of research in curtain groutingdesigns.

Some studies on the behavior of the selection of theoptimal parameters of grouting reinforcement cycle havebeen conducted with experimental and numerical methods.

Considering stability of surrounding rock, He [5] presentedthe reasonable parameters of grouting cycle by using theFLAC software. Based on the theoretical calculation andnumerical simulation, Li et al. [6] proposed the parametersof grouting cycle of XiangAn subsea tunnel. Zhang et al.[7] analyzed the relationship between hydraulic pressureoutside the lining and tunnel drainage. Wang [8] analyzedthe influence of reinforcement cycle thickness on stress anddisplacement of the JiaoZhouWan subsea tunnel, China.

However, few studies have been concerned with thedetails of the influence of reinforcement cycle thicknesson water inflow. To get a better understanding of a keyperformance index of grouting reinforcement cycle, there isa need to analyze the water inflow of tunnel after grouting.

In this paper, based on the fluid-structure interactiontheory [9–13] and orthogonal analysis method, the influenceof reinforcement cycle thickness on water inflow of tunnelafter grouting and stability of surrounding rock was ana-lyzed.The optimal parameters especially reinforcement cycle

Hindawi Publishing CorporationMathematical Problems in EngineeringVolume 2015, Article ID 615736, 15 pageshttp://dx.doi.org/10.1155/2015/615736

2 Mathematical Problems in Engineering

Gully

Strong weathered sandstone, shale

Fault-2

Yonglian tunnel

Figure 1: Cross section of the tunnel.

Strong weatheredsandstone, shale

Fault breccia

Hard fault gougeWeathered

sandstone, shale

q < 15m3/h15m3/h q < 40m3/h⩾

q ⩾ 40m3/h

ZK91+ 355

ZK91+ 330

L1 L2 M1(M2) R2 R1

Soft fault gouge

Figure 2: Geological map of grouting area.

thickness were therefore selected and applied in Yongliantunnel successfully, which provides a reference for similarengineering.

2. Engineering Situation

Yonglian tunnel with a length of 2500m was located onexpressway from Ji’an City to Lianhua City, in JiangxiProvince, China. Because of complex geological conditions,the tunnel was the key engineering of the expressway.

2.1. Geological Conditions. There were a large number ofregional faults and secondary faults with rich water such asfault-2 (see Figure 1) in tunnel. The rock quality designation(RQD) of surrounding rock of tunnel was smaller than 5%.

The geological prospecting (see Table 1) was assessedbased on the boreholes information. A proper geological

Figure 3: Large-scale inrush of mud and water.

Table 1: Parameters of boreholes.

Label Declination (∘) Dip (∘) Length (m)L1 −16 −15 36.9L2 −6 10 35.5M1 0 0 33M2 0 7 33.2R1 17 −17 34.3R2 7 12 32.9

map of grouting area from ZK91+330 to ZK91+355 was thendescribed in Figure 2.

It can be concluded from Figure 2 that the lithology ofgrouting area was mainly strong weathered sandstone, strongweathered shale, fault breccia, and fault gouge. Besides, manywater inflow points were exposed through boreholes with themaximum velocity of 65m3/h.

2.2. Geological Disasters. From July 2 to August 19, 2012, 8times inrush of mud and water with large scale occurred inthe left tunnel, and the volume of gushingmud and water wasmore than 50,000m3 in total (see Figure 3). A large numberof construction machines were damaged during the inrushof mud and water, which hindered the normal constructionseriously.

3. Calculation Model

3.1. Brief Introduction to COMSOL Software. Based on thefinite element theory, the COMSOL software was designedto describe and simulate various physical phenomena. Basedon the COMSOL software, the multiphysical field couplingcan be better simulated and the variousmathematical modelscan be used to describe the physical phenomena. In thepresent paper, porous media flow module and rock and soilmechanics module were used for numerical analysis.

3.2. Calculation Model and Boundary Conditions. Accordingto the actual working conditions of Yonglian tunnel, thecalculation model was composed by lining, grouting rein-forcement cycle, and surrounding rock. As shown in Figure4, the sizes of the calculation model, the tunnel, and thechamber section were adopted as 200m × 180m, 15.58m ×12.39m, and 13.98m × 10.79m, respectively. The distances

Mathematical Problems in Engineering 3

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110100

100

9080

80

7060

60

5040

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3020

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100

0

Figure 4: Calculation model.

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100

9080

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Figure 5: Grid of model.

from the center position of the tunnel to the left boundary, theright boundary, the upper boundary, and the lower boundaryof the calculation model were taken as 100m, 100m, 110m,and 70m, respectively.Themodel was set for steady state withignoring the influence of time.

The left and right boundary were set for roller supportboundary with 𝑢 = 0. The lower boundary was fixed with𝑢, V = 0, and the upper boundary was free. Water wasfree to permeate outside the lining with 𝑝 = 0. The upperboundary was set for a free surface, and the left boundary,right boundary, and lower boundary were impermeable.

3.3. Basic Assumptions

3.3.1. Seepage Field. The groundwater flow was assumed tofollow Darcy’s law, and tunnel drainage was assumed to beachieved through seepage upon the lining. The surroundingrock was taken as homogeneous and isotropic medium. Rockmass below the surface of water was assumed to be saturated.

Porewaterwas in still state before excavation andwas in stableseepage state after excavation.

3.3.2. Stress Field. The grouting reinforcement cycle, sur-rounding rock, and lining were simulated by using theMohr-Coulomb elastic-plastic constitutivemodel.The gravity stressfield was regarded as initial stress field with ignoring tectonicstress field.

3.4. Grid Generation. The freedom triangular grid withspecial elaboration was used (see Figure 5). To improvecalculation accuracy, the grid around the liningwas densified.

The largest and smallest cell sizes were 4m and 0.015m,respectively, and the curvature resolution was 0.25. Basicparameters of grid are shown in Table 2.

4. Parameters Optimization of CurtainGrouting Reinforcement Cycle

4.1. Orthogonal Analysis of Influencing Factors. The improve-ment of the performance of grouting reinforcement cyclemainly shows as the improvement of strength, stiffness,and permeability [14]. Based on the orthogonal analysismethod, the influence of reinforcement cycle thickness, elas-tic modulus, and permeability on the performance of grout-ing reinforcement cycle was analyzed.

4.1.1. Performance Evaluation Index. According to the actualworking conditions of Yonglian tunnel, the parameter ofwater inflow per linear meter of tunnel after grouting, 𝑞, wasregarded as the performance evaluation index of groutingreinforcement cycle.

4.1.2. Basic Parameters. According to related specifications[15, 16], the basic parameters of grouting reinforcement cycle,surrounding rock, and lining are shown in Table 3.

4.1.3. Values of Affecting Factors. The reinforcement cyclethickness, elastic modulus, and permeability are the threemost important factors. The thickness of 𝑑 was regarded asa key research object with six levels. The elastic modulus andpermeability were characterized by the variation coefficientof𝑀 and𝑁 with three levels. One obtains

𝑀 =

𝐸

𝑔

𝐸

𝑤

,

𝑁 =

𝑘

𝑤

𝑘

𝑔

,

(1)

where 𝐸𝑤and 𝐸

𝑔are the elastic modulus of surrounding rock

and grouting reinforcement cycle, respectively, and 𝑘𝑤and

𝑘

𝑔are the permeability of surrounding rock and grouting

reinforcement cycle, respectively.Parameters of reinforcement cycle thickness, elasticmod-

ulus, and permeability are shown in Table 4.

4.1.4. Design of Orthogonal Table and Calculation Results. Asshown in Table 5, orthogonal table was selected to be themixed level table 𝐿

18(6×36). The calculation results are listed

as in Table 5.


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×105

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× 106

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× 105

(b) 𝑑 = 4m

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8

1.6037 × 106

× 105× 106

8.5351 × 105

(c) 𝑑 = 6m

Figure 6: Continued.


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9.3482

×106 ×105

1.6442 × 106 × 105

(d) 𝑑 = 8m

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0.7 0.8 0.90.60.50.40.30.20.11.4 1.61.210 0 1

00

0.80.60.40.2×106 ×106

1.0015 × 1061.6736 × 106

(e) 𝑑 = 10m

Figure 6: Pore water pressure field under different conditions of reinforcement cycle thickness.

Table 2: Parameters of grid.

Parameters Values Parameters ValuesThe smallest quality of unit 0.7396 The largest cell size 4The average quality of unit 0.9726 The smallest cell size 0.015Triangle unit 15503 Curvature resolution 0.25Edge unit 699 The largest cell growth velocity 1.2Endpoint element 26

Table 3: Basic parameters.

Name Size (m) Elasticmodulus (GPa)

Gravity(KN/m3)

Poisson’sratio

Internal frictionangle (∘)

Cohesion(MPa)

Permeability(m2)

The fourth grade surrounding rock 200 × 180 1.5 18.5 0.40 24 0.13 5.0 × 10−11

Grouting reinforcement cycle d 1.5M 19 0.21 45 0.65 𝑁𝐾

𝑤

Lining 0.8 (thickness) 25 25 0.25 50 1.5 5.0 × 10−13


2 4 6 8 100.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

Pore

wat

er p

ress

ure (

MPa

)

Reinforcement cycle thickness (m)

Surrounding rockGrouting reinforcement cycle

Lining

Figure 7: Variation of pore water pressure.

Table 4: Parameters of factors.

Level Factors𝑑 (m) 𝑀 𝑁

1 2 2 202 4 5 503 6 10 1004 8 — —5 10 — —6 12 — —

4.1.5. Calculation of Range. Theaverage value of performanceevaluation index under different levels of factors was calcu-lated as follows:

𝑘

11=

(1340.1 + 996.2 + 699)

3

= 1011.8,

𝑘

12= (1340.1 + 1136.2 + 609.1 + 311

+ 500.3 + 273.9)

1

6

= 695.1,

𝑘

13= (1340.1 + 1136.2 + 1013.5 + 922.8

+ 889.9 + 857.1)

1

6

= 1026.6.

(2)

The calculation values of 𝑘21, 𝑘22, 𝑘23, 𝑘31, 𝑘32, 𝑘33, 𝑘41, 𝑘51,

and 𝑘61are shown in Table 5.

The range of performance evaluation index under differ-ent factors was calculated as follows:

𝑅

1= 𝑘

11− 𝑘

61= 1011.8 − 537.4 = 474.4,

𝑅

2= 𝑘

12− 𝑘

31= 695.1 − 682.1 = 13,

𝑅

3= 𝑘

13− 𝑘

33= 1026.6 − 403.8 = 622.8.

(3)

4.1.6. Analysis of Results. Regarding water inflow of tunnelafter grouting as performance evaluation index of groutingreinforcement cycle (𝑅

3> 𝑅

1> 𝑅

2), the permeability was

assumed to be the most important factor followed by rein-forcement cycle thickness and elastic modulus.

4.2. Variation Characteristics of Pore Water Pressure Field,Stress Field, and Plastic Zone

4.2.1. Pore Water Pressure Field. The pore water pressurefield under the conditions of different reinforcement cyclethickness is shown in Figure 6.

It can be concluded from Figure 6 that the pore waterpressure field varies significantly under different conditionsof reinforcement cycle thickness, showing the funnel shapearound the chamber section. As the thickness of groutingreinforcement cycle increases from 2m to 10m, the funnelshape area gradually decreases from 3.6 times to 1 timeshole diameter. Figure 7 shows that the pore water pressureoutside the grouting reinforcement cycle increases from0.57MPa to 1.01MPa, whereas the pore water pressure ofthe surrounding rock increases from 1.45MPa to 1.67MPa.The pore water pressure outside the lining decreases from0.21MPa to 0.14MPa.

4.2.2. Stress. The stress under different conditions of rein-forcement cycle thickness is shown in Figure 8.


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1 98764052 31 987640×106×106

−2.0224 × 104 −2.0224 × 1049.632 × 106 9.632 × 106

(c) 𝑑 = 6m

Figure 8: Continued.


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(d) 𝑑 = 8m

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×10652 31 87640

×10652 31 87640

8.5387 × 106 8.5387 × 106−2.032 × 104 −2.032 × 104

(e) 𝑑 = 10m

Figure 8: Stress under different conditions of reinforcement cycle thickness.

2 4 6 8 108

9

10

11

12

The m

axim

um st

ress

(MPa

)


Figure 9: Variation of maximum stress around chamber section.


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101214161820

11

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0

0.8 0.90.6 0.70.4 0.50.2 0.30.1

(e) 𝑑 = 10m

Figure 10: Plastic zone under different conditions of reinforcement cycle thickness.


Table 5: Orthogonal table design and calculation results.

LabelFactors

Grouting reinforcement cycle Performance evaluation index of 𝑞L/(d⋅m)

𝑑 𝑀 𝑁

1 1 (2) 1 (2) 1 (20) 1340.12 1 2 (5) 2 (50) 996.23 1 3 (10) 3 (100) 6994 2 (4) 1 1 1136.25 2 2 2 743.96 2 3 3 473.57 3 (6) 1 2 609.18 3 2 3 371.59 3 3 1 1013.510 4 (8) 1 3 31111 4 2 1 922.812 4 3 2 535.713 5 (10) 1 2 500.314 5 2 3 293.815 5 3 1 889.916 6 (12) 1 3 273.917 6 2 1 857.118 6 3 2 481.2𝐾

1𝑗

1011.8 695.1 1026.6𝑘

2𝑗

784.5 697.6 644.4𝑘

3𝑗

664.7 682.1 403.8𝑘

4𝑗

589.8𝑘

5𝑗

561.3𝑘

6𝑗

537.4𝑅

𝑗

474.4 13 622.8

It can be concluded from Figure 8 that the stress fieldvaries significantly under different conditions of reinforce-ment cycle thickness, showing a butterfly shape around thechamber section. As the thickness of grouting reinforcementcycle increases from 2m to 10m, the maximum stress aroundthe chamber section gradually decreases from 11.47MPa to8.54MPa (see Figure 9).

4.2.3. Plastic Zone. The plastic zone under different condi-tions of reinforcement cycle thickness is shown in Figure 10.

It can be concluded from Figure 10 that the plastic zonevaries significantly under different conditions of reinforce-ment cycle thickness, showing a butterfly shape around thechamber section. As the thickness of grouting reinforcementcycle increases from 2m to 10m, the butterfly shape areaaround the chamber section decreases gradually.

4.2.4. Conclusions. As the thickness of grouting reinforce-ment cycle increases from 2m to 10m, the maximum stress,

pore water pressure, and plastic zone outside the lining alldecrease, indicating that the strength, stiffness, and perme-ability of surrounding rock are improved significantly.

4.3. Parameters Optimization of Curtain Grouting Reinforce-ment Cycle. As previously described, the water inflow oftunnel after grouting was regarded as the performanceevaluation index of grouting reinforcement cycle, and thethickness of reinforcement cycle and permeability have asignificant influence on the water inflow. Considering thedual requirements for economy and safety, there is a needto select the minimum safe thickness and permeability ofgrouting reinforcement cycle.

The curves of water inflow per linearmeter of tunnel aftergrouting are shown in Figure 11.

It can be seen from Figure 11 that the water inflow perlinear meter of tunnel is 1757.4 L/(d⋅m) when the thicknessof reinforcement cycle is 0m, indicating a serious threatto the tunnel safety. According to the curve, under the


0 2 4 6 8 10 12 14 16 18 200

200

400

600

800

1000

1200

1400

1600

1800


Wat

er in

flow

per

line

ar m

eter

(m3/(

d·m))

N = 1

N = 2

N = 5

N = 10

N = 20 N = 300

N = 200

N = 150

N = 100

N = 50

Figure 11: Curves of water inflow per linear meter after grouting.

Cycle A

Cycle B

Cycle A

Cycle B

Row C

Row D

Row E

Row F

Row G

Row HCycle I

Excavation contour Curtain grouting holes

Reinforcement area

InvertRubble concrete

Figure 12: Design of curtain grouting.

conditions of the same permeability variation coefficient 𝑁,the water inflow per linear meter decreases gradually withincreasing grouting reinforcement cycle thickness. However,when the grouting reinforcement cycle thickness is morethan 8m, the water inflow is steady approximately. Under theconditions of same reinforcement cycle thickness, the waterinflow per linear meter decreases gradually with an increasein permeability variation coefficient 𝑁. However, when thepermeability variation coefficient 𝑁 is more than 100, thewater inflow is steady approximately.

It can be concluded that the thickness of 8m and thepermeability variation coefficient 𝑁 of 100 are the optimalparameters of grouting reinforcement cycle.

5. Field Test of Curtain Grouting inYonglian Tunnel

5.1. Design Scheme of Curtain Grouting. The key parametersof curtain grouting were designed as follows.

(1) According to the results of numerical simulation,the thickness of reinforcement cycle was adoptedas 8m. Based on field tests, the terminal distancebetween grouting holes, diffusion radius of groutingwere designed to be 8m, 3.5m, and 2m, respectively.

(2) Because of stress concentration, the grouting holeswere densified near the foot arch and arch wall to


Grouting holes

Figure 13: Construction of curtain grouting.

0 2 4 6 8 10 12 14 16 18 200

10

20

30

40

50

60

70

80

90

Injection velocityInjection pressure

Inje

ctio

n ve

loci

ty (L

/min

)

0

1

2

3

4

5

6

7

8

Inje

ctio

n pr

essu

re (M

Pa)

t (h)

Figure 14: 𝑃-𝑄-𝑡 curve during grouting.

strengthen the reinforcement, and 153 grouting holesincluding 124 curtain grouting holes, 21 vault groutingholes, and 8 supplement grouting holes were designedin total (see Figures 12 and 13).

(3) The cement-GT groutingmaterial was used in curtaingrouting which had the advantages of controllable geltime, high strength, and good permeability resistanceperformance [17, 18].

5.1.1. 𝑃-𝑄-𝑡 Curve during Grouting. Injection pressure andvelocity which can reflect the diffusion characteristics ofslurry were recorded during grouting.

It can be seen from Figure 14 that the maximum ofinjection pressure and velocity can reach 4.1MPa and 83L/min, respectively.

Fault gouge was reinforced by filling, compaction, andsplitting effect of the injected slurry. Initially, the slurry playeda compaction role, and the injection pressure needed toincrease to overcome the initial stress of the medium. Due tolow porosity, the injection velocity was relatively low at thisstage. When the injection pressure was enough to overcomethe initial stress, the medium was split by slurry with theformation of a large space. Therefore, the injection pressure

B

G1

G2(A)

G3

C

Figure 15: Monitoring points.

decreased rapidly, whereas the injection velocity increasedrapidly.

In a word, the injection pressure and velocity show awavelike law, indicating that fault gouge was reinforced byfilling, compaction, and splitting effect of the injected slurry.

5.2. Examination of Reinforcement Effect. Reinforcementeffect for unfavorable geology area was examined by exam-ination holes, 𝑃-𝑄-𝑡 curve, surrounding rock deformationmonitoring, and excavation.

5.2.1. Examination Holes. According to relevant standardsand engineering cases [19, 20], the design of examinationholes must be representative and comprehensive. 21 exami-nation holes were then designed to evaluate reinforcementeffect. For example, lithology andwater inflow exposed by JC-13 hole and JC-16 hole are shown in Table 6.

Note that a lot of mixed solidification bodies of slurry androck were exposed by examination holes, indicating that theunfavorable geology area was reinforced effectively.

The velocity of water inflow of JC-13 hole and JC-16 holewas 144 L/d⋅m−1 and 72 L/d⋅m−1, respectively, which wereless than that of relevant engineering cases, indicating thatthe thickness of reinforcement cycle designed by results ofnumerical simulation is suitable.

5.3. Surrounding Rock Deformation Monitoring. Two mon-itoring sections were designed at ZK91+333 and ZK91+341to monitor the vault settlement and peripheral convergenceof primary support during the excavation of tunnel, and themonitoring points were arranged as shown in Figure 15. Themonitoring results are shown in Figure 16.

Figure 16 shows that themaximumvelocity of vault settle-ment and peripheral convergence is smaller than 2mm/d andthe average velocity is smaller than 0.5mm/d. The accumu-lative value is relatively stable. It can be concluded that theself-stability of surrounding rock can be improved greatlyby curtain grouting, which can ensure the safety of tunnelconstruction. In other words, the thickness of reinforcementcycle can be adopted as 8m.


8/16 8/17 8/18 8/19 8/20 8/21

0.0Va

ult s

ettle

men

t (m

m)

Date

−4.0

−3.5

−3.0

−2.5

−2.0

−1.5

−1.0

−0.5

(a) Vault settlement curve of ZK91+333

8/16 8/17 8/18 8/19 8/20 8/21

Perip

hera

l con

verg

ence

(mm

)

Date

−18

−16

−14

−12

−10

−8

−6

−4

(b) Peripheral convergence curve of ZK91+333

9/9 9/10 9/11 9/12 9/13 9/14

0

Vaul

t set

tlem

ent (

mm

)

DateG1G2

G3

−8

−7

−4

−3

−2

−1

−5

−6

(c) Vault settlement curve of ZK91+341

9/9 9/10 9/11 9/12 9/13 9/14

0

Perip

hera

l con

verg

ence

(mm

)

DateABAC

BC

−8

−7

−4

−3

−2

−1

−5

−6

(d) Peripheral convergence curve of ZK91+341

Figure 16: Monitoring data.

5.4. Slurry Veins Exposed by Excavation. As shown in Figure17, two representative regions are selected to illustrate thedistribution of slurry veins. Faultmedium is tightly combinedwith consolidation body of slurry.

The sizes of slurry veins are shown in Table 7. There are16 slurry veins including primary and secondary veins in tworegions with the maximum width of 460mm.

It can be concluded from Figure 17 and Table 7 that thestrength of rock was improved significantly by curtain grout-ing, indicating the reliable reinforcement cycle thickness of8m.

6. Conclusions

(1) Regarding water inflow of tunnel after grouting asperformance evaluation index of grouting reinforce-ment cycle, it was found that permeability was the

most important factor followed by reinforcementcycle thickness and elastic modulus.

(2) Pore water pressure field showed the funnel shape,and the stress field and plastic zone showed thebutterfly shape around the chamber section under theconditions of different reinforcement cycle thickness.With the increase of thickness, the pore water pres-sure upon lining, stress, and plastic zone decreasedwith different levels.

(3) According to the results of numerical simulation, thethickness of reinforcement cycle and permeabilitywere, respectively, selected to be 8m and 1/100 ofthe surrounding rock permeability as the optimalparameters of curtain grouting reinforcement cycle.After application in Yonglian tunnel, it was provedto be effective, reliable, and suitable by means of


Table 6: Lithology and water inflow exposed by JC-13 and JC-16.

Label Lithology Velocity of water inflow (L/d⋅m−1)

JC-133m–6m: solidification body of slurry;7m–16m: mixed solidification body of slurry and fault gouge;17m–25m: mixed solidification body of slurry and fault breccia;26m–31m: mixed solidification body of slurry and fault gouge.

144

JC-163m–9m: mixed solidification body of slurry and fault gouge;10m–21m: mixed solidification body of slurry and fault breccia;22m–31m: mixed solidification body of slurry and fault gouge;32m–35m: solidification body of slurry.

72

Vein-3

Vein-2 Vein-1

Vein-4 Vein-5

Vein-6

Vein-7Vein-8

Vein-1Vein-2

Vein-3

Vein-4

Vein-5

Vein-6

Vein-7

Vein-8

Figure 17: Slurry veins exposed by excavation.

Table 7: Sizes of slurry veins.

Region Label Width (mm) Classes

1

Vein-1 13 SecondaryVein-2 122 PrimaryVein-3 9 SecondaryVein-4 11 SecondaryVein-5 460 PrimaryVein-6 14 SecondaryVein-7 27 SecondaryVein-8 12 Secondary

2

Vein-1 8 SecondaryVein-2 9 SecondaryVein-3 17 SecondaryVein-4 33 SecondaryVein-5 62 PrimaryVein-6 26 SecondaryVein-7 15 SecondaryVein-8 23 Secondary

examination holes, 𝑃-𝑄-𝑡 curve, surrounding rockdeformationmonitoring, and excavation, providing areference for similar engineering to some extent.

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper.

Acknowledgments

This project is supported by National Natural Science Foun-dation of China (Grant no. 51209128), Support Plan forExcellent Talents by Ministry of Education in the NewCentury (Grant no. NCET-11-0317), and the Ph.D. ProgramsFoundation of Ministry of Education of China (Grant no.20130131110032).

References

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