Dynamics Oil

8/11/2019 Dynamics Oil

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SOL DYNAM

CSSO

L DYNAM

CS

Dynamics SoilDynamics SoilPropertiesProperties

Derin N. UralDerin N. Ural


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Dynamic Soil PropertiesDynamic Soil Properties

Measurement of properties through field tests:Measurement of properties through field tests:

1.1. Low Strain TestsLow Strain Tests

These tests have shear strains < 0.001%These tests have shear strains < 0.001%

Based on theory of linear materialsBased on theory of linear materials


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Dynamic Soil PropertiesDynamic Soil Properties1. LOW STRAIN TESTS1. LOW STRAIN TESTS

A) Seismic Reflection TestA) Seismic Reflection Test

B)B) Seismic Refraction TestSeismic Refraction Test

C)C) Suspension Logging TestSuspension Logging Test

D)D) SteadySteady--State Vibration TestState Vibration Test

E)E) Spectral Analysis of Surface Wave Test (SASW)Spectral Analysis of Surface Wave Test (SASW)

F)F) Seismic CrossSeismic Cross--Hole TestHole TestG)G) Seismic DownSeismic Down--Hole TestHole Test

H)H) Seismic Cone TestSeismic Cone Test


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AA)) SeismicSeismic ReflectionReflection Method:Method:

sourcesource recieverreciever

2i2iHH

xx

vvp1p1

vvp2p2From source to reciever,From source to reciever,

ttdirectdirect = x/ v= x/ vp1p1

i = tani = tan --11 ( x/2H)( x/2H)

Find tFind treflectedreflected & H& H


LOW STRAIN TESTSLOW STRAIN TESTS


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BB)) Seismic Refraction Method:Seismic Refraction Method:Seismic waves have different velocities in different typesSeismic waves have different velocities in different typesof soil. Waves are generated either by explosives, or strikingof soil. Waves are generated either by explosives, or striking

a metal plate with a hammer (geophone & seismograph ).a metal plate with a hammer (geophone & seismograph ).

Two types of stress waves:Two types of stress waves:

P WavesP Waves : plane waves: plane waves200 m/s in sands to 2500 m/s in clays200 m/s in sands to 2500 m/s in clays

S WavesS Waves : shear waves: shear waves


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Seismic Refraction MethodSeismic Refraction Method -- continued:continued:

PrinciplePrinciple::A) Longitudinal waves travel in straight lines in aA) Longitudinal waves travel in straight lines in a

medium of constant density.medium of constant density.

B) Waves are reflected when they come in contact withB) Waves are reflected when they come in contact withsoil strata of different density.soil strata of different density.

C) Determine seismic velocities & compare with knownC) Determine seismic velocities & compare with knownvalues.values.




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Seismic Refraction MethodSeismic Refraction Method -- continued:continued:

PP--wave velocity:wave velocity:

pp= E /(= E /(/g) */g) * (1(1--)/((1)/((1--22)(1+)(1+ )))) :: TTRR


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C) Suspension Logging TestC) Suspension Logging Test

Used commonly in petroleum exploration tests,Used commonly in petroleum exploration tests,

An impulsive pressure wave is generated in aAn impulsive pressure wave is generated in aborehole filled with water.borehole filled with water.

It is effective at great depths (up to 2 km!)It is effective at great depths (up to 2 km!)

Dynamic Soil PropertiesDynamic Soil PropertiesLOW STRAIN TESTSLOW STRAIN TESTS


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E) Spectral Analysis of Surface Wave Test (SASW)E) Spectral Analysis of Surface Wave Test (SASW)

Shallow Seismic ExplorationShallow Seismic Exploration

Quick, no borehole requiredQuick, no borehole required up to 100m depthup to 100m depth

Impulse or random noise sourceImpulse or random noise source output recordedoutput recordedand transformed to frequency domain by FFTand transformed to frequency domain by FFT

Rayleigh phase velocity vs. Wavelength is obtainedRayleigh phase velocity vs. Wavelength is obtained

sourcesourcerecieverreciever recieverreciever

dd11dd22



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FF)) Cross HoleCross Hole TestTest::Two holes are drilled a distance, L, apart. A verticalTwo holes are drilled a distance, L, apart. A vertical

impulse is created at the bottom of one of theimpulse is created at the bottom of one of theboreholes by an impulse. The shear waves generatedboreholes by an impulse. The shear waves generatedare recorded by a transducer at the other borehole.are recorded by a transducer at the other borehole.

MethodMethodShear wave velocity:Shear wave velocity: Vs = L / tVs = L / tShear modulusShear modulus : G=V: G=Vss

22 / g/ g



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FF)) DownDown /or Up/or Up HoleHole TestTest::OneOne holesholes isis drilled. A vertical impulse is created atdrilled. A vertical impulse is created at

the bottomthe bottom/or top/or top of one of the boreholes by anof one of the boreholes by animpulse. The shear waves generated are recordedimpulse. The shear waves generated are recordedby a transducer at theby a transducer at the toptop/or bottom/or bottom of theof theborehole.borehole.



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GG)) Seismic ConeSeismic Cone TestTest::

DownDown--hole testhole test withoutwithout thethe borehole.borehole.

Cone penetrometer has an accelerometer justCone penetrometer has an accelerometer justabove the friction sleeve.above the friction sleeve.



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22)) High Strain TestsHigh Strain Tests::

Soil strength is determined.Soil strength is determined.

A)A) Standard Penetration TestStandard Penetration Test

B)B) Cone Penetration TestCone Penetration Test

C)C) Dilatometer TestDilatometer TestD)D) Pressuremeter TestPressuremeter Test



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A) Standard Penetration TestA) Standard Penetration Test

Used for sandy soilsUsed for sandy soils

(N(N11))6060 = N C= N CNN (E(Emm / 0.6 E/ 0.6 Effff))Where :Where :

N : inN : in--situ SP Numbersitu SP Number

CCNN : overburden correction: overburden correctionEm : Hammer energyEm : Hammer energy

EEffff : theoretical free: theoretical free--fall hammer energyfall hammer energy

Dynamic Soil PropertiesDynamic Soil PropertiesHIGH STRAIN TESTSHIGH STRAIN TESTS


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B)B) CONE PENETRATION TESTCONE PENETRATION TEST

The end resistance of the cone at any depthThe end resistance of the cone at any depth

called thecalled the cone penetration resistancecone penetration resistanceis (qis (qcc))measured. qmeasured. qcc is the force required to advance theis the force required to advance thecone divided by the end area. Unlike the SPT, soilcone divided by the end area. Unlike the SPT, soil

samples cannot be recovered during the CPT.samples cannot be recovered during the CPT.

Applicable Not Applicable

Soft clays Very stiff clays

Fine to medium course

sands

Hard clays

gravels



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B)B) CONE PENETRATION TESTCONE PENETRATION TEST(contd)(contd)

Types of cones:Types of cones: Mechanical Cone (Dutch ConeMechanical Cone (Dutch Cone -- reading everyreading every

200 mm)200 mm)

Electrical Cone (constant readings)Electrical Cone (constant readings)

ElectricalElectrical PiezoconePiezocone

Friction Ratio :Friction Ratio :

FFRR== qqSS/q/qcc *100 (%)*100 (%)FFRR > 5% :clays5% :clays



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B)B) CONE PENETRATION TESTCONE PENETRATION TEST(contd)(contd)

qqCC qqSS FFRR uu((MpaMpa) (kPa) (%)) (kPa) (%) (kPa)(kPa)

Data collected during electrical CPTData collected during electrical CPT

Note:Note: qqCC can be correlated to :can be correlated to : ,D,Drr ,C,CUU, N, N



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C)C) THETHE DILATODILATOMETER TESTMETER TEST

At 10 to 20 cm, test is stopped and membrane is inflated byAt 10 to 20 cm, test is stopped and membrane is inflated bypressurized gas. Pressure where membrane moves 0.05 mmpressurized gas. Pressure where membrane moves 0.05 mm(p(poo) and center moves 1.1 mm (p) and center moves 1.1 mm (p11) is recorded.) is recorded.

Parameters obtained:Parameters obtained:

Material index :Material index : IIDD == (p(p11 pp00)) / (p/ (p11 uu00))

Horizontal Stress index :Horizontal Stress index : KKDD == (p(p00 uu00) /) / V0V0

Dilatometer Index :Dilatometer Index : EEDD = 34.7 (p= 34.7 (p11 pp00))



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D)D) THE PRESSUREMETER TESTTHE PRESSUREMETER TESTTheThe PressuremeterPressuremeter test is an intest is an in--situ test developed bysitu test developed byMenard in 1956. Applicable for :Menard in 1956. Applicable for : soft claysoft clay ,, fine tofine tomediummediumsandssands. The device consists of three parts. The device consists of three parts (top,(top, cell andcell andbottom) as shown below:bottom) as shown below:



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D)D) THE PRESSUREMETER TESTTHE PRESSUREMETER TEST

Also, the relationship between E and G is given byAlso, the relationship between E and G is given by

E=2(1+E=2(1+)G)G G=VG=V00

p/p/ VV

PressuremeterPressuremeter test results can also be used totest results can also be used todetermine thedetermine the at rest earth pressure coefficientat rest earth pressure coefficient::

KK00=p=p00//

Note:In France, shallow and deep foundation design is allNote:In France, shallow and deep foundation design is all

based onbased on pressuremeterpressuremeter tests.tests.



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Other:Other:

Geotomography:Geotomography:

InIn--situ densitysitu density Low strain stiffnessLow strain stiffness



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LABORATORYLABORATORY TESTTESTSS

A)A) Resonant Column TestResonant Column Test

Torsional or axial loadingTorsional or axial loading

Frequency and amplitude are controlledFrequency and amplitude are controlled

T = GJ dT = GJ d/dz, I/I/dz, I/Ioo == nnh/h/vvss tan ( wtan ( wnnh/h/vvss ))

h: specimen heighth: specimen heightI: mass moment of inertiaI: mass moment of inertia

J: Polar moment of inertiaJ: Polar moment of inertia

Example!Example!



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B) Ultrasonic Pulse TestB) Ultrasonic Pulse Test

Wave propogation velocities measuredWave propogation velocities measured

Good for soft soilsGood for soft soils



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C) Piezoelectric Bender Element TestC) Piezoelectric Bender Element Test

Vs measuredVs measured


+voltage -voltageDirectionof wave

t : between pulses

x: distance betweenbender elements


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2. High Strain Element Tests2. High Strain Element TestsA)A) Cyclic Triaxial TestCyclic Triaxial Test

B)B) Cyclic Direct Simple Shear TestCyclic Direct Simple Shear TestC)C) Cyclic Torsional Shear TestCyclic Torsional Shear Test

D)D) Model TestsModel Testsi) Shaking Table Testsi) Shaking Table Tests

ii) Centrifuge Testsii) Centrifuge Tests



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A)A) Cyclic Triaxial TestCyclic Triaxial Test

Measures dynamic soil properties,Measures dynamic soil properties,

Axial stress is cycled at 1 HzAxial stress is cycled at 1 Hz

Dynamic Soil PropertiesDynamic Soil PropertiesHigh Strain TestsHigh Strain Tests


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D)D) Model TestsModel Tests

Prototype structures are cyclically loaded.Prototype structures are cyclically loaded.

(i) Up to 1g acceleration: SHAKING TABLE(i) Up to 1g acceleration: SHAKING TABLE

(ii) Increased Gravitational Fields: CENTRIFUGE(ii) Increased Gravitational Fields: CENTRIFUGE

Challenges: Similitude & boundary effectsChallenges: Similitude & boundary effects



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D)D) Model TestsModel Tests

(i)(i) SHAKING TABLESHAKING TABLE

MDOFMDOF

Driven by servohydraulic actuators whoseDriven by servohydraulic actuators whose

dynamic loading capacities are controlled bydynamic loading capacities are controlled by

hydraulic pumpshydraulic pumps



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LABORATORYLABORATORY TESTTESTSSD)D) Model TestsModel Tests

(ii) CENTRIFUGE(ii) CENTRIFUGE

1/N scale model located at distance,r, from axis1/N scale model located at distance,r, from axis

of centrifuge is rotated atof centrifuge is rotated at = = ((N/r)N/r)

Acceleration is raised N times gracityAcceleration is raised N times gracity

Overall behavior of prototype (displ/stress)Overall behavior of prototype (displ/stress)

should be same as fullshould be same as full--scale modelscale model

i.e., 30 m dam will be 30 cm, and since size 1/100, accelerationi.e., 30 m dam will be 30 cm, and since size 1/100, acceleration: 100g!: 100g!


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