Preface ........................................................ xv
Section 1: True triaxial testing techniques and procedures
1 True-triaxial testing techniques for rocks—State of the
art and future perspectives
X. Li, L. Shi, B. Bai, Q. Li, D. Xu & X. Feng ................ 3
1 Introduction .............................................. 3
2 Development history of true triaxial test techniques for
testing rocks ............................................. 5
2.1 Types of TTT apparatuses ............................. 5
2.2 Type-I: Rigid platen type ............................ 6
2.3 Type-II: Flexible medium type ........................ 7
2.4 Type-Ill: Mixed type ................................. 8
2.5 Comparison of various kinds of TTT apparatuses ....... 9
3 True-triaxial rock testing techniques in China ........... 10
3.1 Development and application of TTT apparatuses for
rocks in China ...................................... 10
3.2 Newly developed TTT apparatuses for rocks in China .. 12
4 Problems and future perspectives of TTT for rocks ........ 14
4.1 Problems ............................................ 14
4.2 Future perspectives ................................. 15
5 Conclusions .............................................. 16
2 Numerical analysis of loading boundary effects in
Mogi-type true triaxial tests
L. Shi, X. Li, B. Bai, Q. Li & X. Feng ...................... 19
1 Introduction ............................................. 19
2 Influence of platen thickness ............................ 20
2.1 Numerical model ..................................... 20
2.2 Results and discussion .............................. 21
3 Influence of loading eccentricity ........................ 23
4 Influence of the end friction effect ..................... 24
4.1 Introduction of the end friction effect ............. 24
4.2 Numerical scheme and associated parameters .......... 25
4.3 Results and discussion .............................. 26
5 Influence of the corner effect ........................... 28
5.1 Influence on the uniform distribution of stress ..... 28
5.2 Influence on the failure surface .................... 28
6 Conclusions .............................................. 32
3 Design and development of integrated true triaxial rock
testing system
L. Lombos, D.W. Roberts & M.S. King ......................... 35
1 Introduction ............................................. 35
2 Polyaxial imaging cell ................................... 35
2.1 Mechanical/hydraulic requirements ................... 36
2.2 Electrical/electronic requirements .................. 36
2.3 Additional requirements ............................. 36
3 Integrated true triaxial rock testing system ............. 36
3.1 Polyaxial Test (PAT) Rig or True Triaxial Loading
Frame ............................................... 36
3.2 Polyaxial Imaging Cell—True Triaxial Test Cell-
Geophysical Imaging Cell "B" ........................ 37
4 Conclusions .............................................. 49
4 The FPMs (UMons-Belgium) device for investigating the
mechanical behavior of materials subjected to true
triaxial compression
J.-P. Tshibangu & F. Descamps ............................... 51
1 Introduction ............................................. 51
2 Description of the FPMs true triaxial or polyaxial
cell ..................................................... 51
3 Test control and stress/strain paths ..................... 52
3.1 General presentation ................................ 52
3.2 Stress path control ................................. 53
3.3 Strain path control ................................. 54
3.4 Creep test .......................................... 54
4 Interpretation of the data obtained from compressive
tests .................................................... 54
4.1 Processing of the stress-strain data ................ 54
4.2 Building 3D envelopes ............................... 55
5 Selected results for several rock materials .............. 56
5.1 Rock materials ...................................... 56
5.2 Identifying the behavior of a rock material ......... 56
5.3 Mechanical characteristics and evolution with
respect to confining stresses ....................... 57
6 Plastic behavior and limiting envelopes .................. 57
6.1 Hardening and dilatancy ............................. 57
6.2 Evolution of hardening on the octahedral plane ...... 57
7 Conclusions .............................................. 59
5 Study of the failure and deformability of jointed rock
masses using large rock block specimens
K. Suzuki ................................................... 61
1 Introduction ............................................. 61
1.1 Scope ............................................... 61
1.2 Specimen size—Representative Elementary Volume ...... 61
2 Shear test of large rock block specimens ................. 62
2.1 Apparatus—Multipurpose Testing Machine for rock
masses .............................................. 62
2.2 Sampling method ..................................... 63
2.3 Rock block specimen ................................. 63
2.4 Method of testing ................................... 63
3 Test results and discussion .............................. 64
3.1 Strength properties ................................. 64
3.2 Deformational properties ............................ 67
3.3 Similarity rule of joint geometry in terms of
crack tensor ........................................ 67
4 Conclusions .............................................. 70
6 The hollow cylinder test as an alternative to true
triaxial loading of prismatic rock specimens
C. Dinis da Gama ............................................ 73
1 Introduction ............................................. 73
2 Equipment and tests ...................................... 73
3 Interpretation of the results obtained ................... 77
4 Comparisons with triaxial tests .......................... 79
5 Conclusions .............................................. 82
7 Design and fabrication of a low cost true triaxial cell
for testing multiple size specimens
A.K. Schwartzkopff, S. Priest, N. Melkoumian & J.A. Egudo ... 83
1 Introduction ............................................. 83
2 Problem definition ....................................... 83
3 Preliminary design ....................................... 83
4 Sourcing hydraulic jacks ................................. 84
5 Challenges of the true triaxial cell ..................... 84
5.1 Design challenges ................................... 84
5.2 Manufacturing challenges ............................ 88
5.3 Implementation challenges ........................... 88
6 Development of engineering plans ......................... 88
6.1 Strengths of software ............................... 88
6.2 Input parameters .................................... 88
7 Manufacture .............................................. 88
8 Design and assembly of hydraulics ........................ 89
9 Practical use of the cell ................................ 90
9.1 Calibration of hydraulics ........................... 90
9.2 Calibration of the strains on the true triaxial
cell under load ..................................... 90
10 True triaxial testing .................................... 93
10.1 Specimen rock type .................................. 93
10.2 Test results ........................................ 93
Section 2: Test results: Strength, deformability, failure
mode, permeability, acoustic emission, elastic wave velocity
8 Mechanical behavior of rocks under true triaxial
compression conditions — A review
M. Kwaśniewski .............................................. 99
1 Introduction ............................................. 99
2 True triaxial compression tests on cubic and
rectangular prismatic samples ........................... 105
2.1 True triaxial compression tests using solid
pistons ............................................ 105
2.2 Compression tests using fluid membranes
(flat-jacks) ....................................... 106
2.3 Compression tests using solid pistons and oil
pressure ........................................... 107
3 Review of the true triaxial test results ................ 108
4 Strength of rocks under true triaxial compression
conditions .............................................. 117
4.1 Mogi's failure hypothesis .......................... 117
4.2 Review of the empirical data on true triaxial
strength of rocks .................................. 118
5 Summary and final remarks ............................... 131
9 How I developed a true triaxial rock testing machine
K. Mogi .................................................... 139
1 Introduction ............................................ 139
2 Experimental research at MIT ............................ 140
3 Development of the Mogi-type true triaxial machine ...... 140
3.1 Uniaxial compressive strength and sample shape ..... 140
3.2 Axial compressive strength and fracture angle
under various confining pressures .................. 141
4 Design and construction of the Mogi-type triaxial
testing machine ......................................... 148
5 Summary of experimental results ......................... 151
10 True triaxial testing reveals hitherto unknown rock
mechanical properties
B. Haimson ................................................. 159
1 Introduction ............................................ 159
2 Compressive strength .................................... 160
3 Strength criterion ...................................... 160
4 Failure modes ........................................... 161
5 Fault angle and direction ............................... 162
6 Dilatancy ............................................... 163
7 Micromechanical features of brittle failure under TTT ... 164
8 Brief discussion ........................................ 164
11 Imaging the effect of the intermediate principal stress
on strength, deformation and transport properties of
rocks using seismic methods
R.P. Young, M.H.B. Nasseri & L. Lombos ..................... 167
1 Introduction ............................................ 167
1.1 Effect of intermediate principal stress ............ 167
1.2 Rock Fracture Dynamic Facility (RFDF) .............. 168
2 Experimental set up and testing procedure ............... 169
2.1 Sample preparation for true triaxial experiment .... 169
2.2 True triaxial geophysical imaging cell (TTGIC) ..... 170
2.3 MTS polyaxial testing machine ...................... 171
2.4 Permeability and rubber membrane skeleton—MM seal
pressure system .................................... 171
2.5 Ultrasonic wave velocity and acoustic emission .... 172
3 Results and discussion .................................. 172
3.1 True triaxial strength and deformational
responses .......................................... 172
3.2 Evolution of 3D ultrasonic wave velocities with
true triaxial stresses ............................. 173
3.3 Acoustic emission data processing, AE hits and
locations .......................................... 175
3.4 3D directional permeability of Fontainebleau
sandstone .......................................... 176
4 Conclusions ................................................ 178
12 Mechanical characteristics of rock salt determined using
the Absolute Triaxial Testing (ATT) machine
S. Sakurai & S. Serata ..................................... 181
1 Introduction ............................................ 181
2 Absolute Triaxial Testing (ATT) ......................... 182
2.1 ATT machine ........................................ 182
2.2 Specimens .......................................... 182
2.3 Measuring devices .................................. 183
3 Testing procedure ....................................... 184
3.1 Stress-strain relationship ......................... 184
3.2 Yielding stress .................................... 184
3.3 Failure stress ..................................... 184
3.4 Creep tests ........................................ 184
4 Experimental results .................................... 184
4.1 Yielding stress condition .......................... 184
4.2 Failure stress condition ........................... 186
4.3 Failure stress condition under two different
confinement stresses ............................... 186
4.4 Time-dependent characteristics of rock salt ........ 188
5 Failure criterion ....................................... 189
5.1 Octahedral shearing stress ......................... 189
5.2 Triaxial testing results ........................... 189
5.3 Proposed failure criterion ......................... 190
6 Conclusions and final remarks ........................... 191
13 Seismic wave velocity anisotropy in Westerly granite
under a true triaxial compression test
M. Takahashi ............................................... 193
1 Introduction ............................................ 193
2 Previous experiments under general stress state ......... 194
3 The true triaxial testing system and measurement
methods of seismic wave velocity ........................ 195
4 Experimental results .................................... 196
5 Discussion .............................................. 198
6 Conclusions ............................................. 202
14 Deformation and strength characteristics of Kimachi
sandstone under confined compression and extension test
conditions
N. Takahashi, M. Takahashi, H. Park, Y. Fujii &
T. Takemura ................................................ 203
1 Introduction ............................................ 203
2 Experimental procedure .................................. 204
2.1 Testing material ................................... 204
2.2 Apparatus .......................................... 204
2.3 Testing method ..................................... 205
3 Results and discussion .................................. 207
3.1 Stress-strain relationships ........................ 207
3.2 Comparison of strength between compression and
extension test conditions .......................... 207
3.3 Comparison of volumetric strain at failure
between compression and extension test conditions .. 208
4 Conclusions ............................................. 209
Section 3: Failure mechanisms and failure criteria
15 Estimating the parameters for a three-dimensional failure
criterion for rocks from a single test
P.V. Lade .................................................. 213
1 Introduction ............................................ 213
2 Three-dimensional failure criterion ..................... 216
3 Tensile strength of rocks ............................... 217
4 Parameter determination ................................. 218
5 Parameter values for rocks .............................. 218
6 Parameters from a single test ........................... 220
7 Conclusions ............................................. 222
16 A new failure criterion for transversely isotropic rocks
and its validation against true triaxial tests
J. Pei & H.H. Einstein ..................................... 223
1 Introduction ............................................ 223
2 Experimental observations ............................... 224
3 The Anisotropic Matsuoka-Nakai (AMN) criterion .......... 225
3.1 The Normal Stress Space ............................ 225
3.2 The original Matsuoka-Nakai criterion .............. 226
3.3 The Anisotropic Matsuoka-Nakai criterion ........... 228
4 Validation of the AMN criterion ......................... 230
5 Conclusions ............................................. 233
17 Stress path dependency of failure mechanism from the
viewpoint of dilatant behavior
Т. Takemura, К Suzuki, A. Golshani & M. Takahashi .......... 235
1 Introduction ............................................ 235
2 Testing material and procedure .......................... 236
3 Results ................................................. 238
4 Discussion and concluding remarks ....................... 240
18 Weakness plane model to simulate effects of stress states
on rock strengths
Y. Fujii ................................................... 243
1 Introduction ............................................ 243
2 Weakness plane model .................................... 243
3 True triaxial test ...................................... 245
4 Uniaxial tension and Brazilian tests .................... 246
5 Extension test ....................................... 246
6 Concluding remarks ................................... 248
Section 4: Applications to geoengineering and geosciences
19 A modified true triaxial test system that allows
a specimen to be unloaded on one surface
M.C. He, X.N. Jia, W.L. Gong, G.J. Liu & F. Zhao ........... 251
1 Introduction ............................................ 251
2 The mechanism of rockbursts and experimental setup ...... 252
2.1 The mechanism of rockbursts ........................ 252
2.2 Functions and requirements of the experimental
setup .............................................. 252
3 Rockburst experiment system for single face unloading ... 255
4 Information measuring system for rockburst experiments .. 256
4.1 Data acquisition system ............................ 256
4.2 Acoustic emission monitoring system ................ 256
4.3 High-speed image recording system .................. 256
4.4 Infrared thermal monitoring system ................. 257
5 Experimental result analyses ............................ 258
5.1 Distribution of rockburst sampling sites ........... 258
5.2 Characteristics of the unloading rate on a single
surface ............................................ 260
5.3 Rockburst time and rockburst classification ........ 261
5.4 Analysis of the typical results of rockburst
tests .............................................. 261
6 Conclusions ............................................. 264
20 Seismic quiescence and foreshock activity preceding the
2007 Niigata-ken Chuetsu-oki earthquake (M6.8) in Japan
K. Mogi .................................................... 267
1 Introduction ............................................ 267
2 Long term earthquake forecasting ........................ 267
3 Precursory seismicity before the 2007 main shock ........ 268
3.1 Previous findings .................................. 269
3.2 Seismic quiescence ................................. 271
3.3 Foreshock activity ................................. 272
4 Discussion (predictive information) ..................... 275
5 The Kashiwazaki-Kariwa nuclear power plants and the
2007 Chuetsu-oki earthquake (M6.8) ...................... 276
6 Conclusions ............................................. 277
Appendix 1—Search for seismic quiescence ................... 278
Appendix 2 ................................................. 280
21 Stress state effect on the mechanical behavior of coals
under true triaxial compression conditions
A.D. Alexeev, V.N. Revva & A.V. Molodetski ................. 281
1 Introduction ............................................ 281
2 Methods and materials ................................... 282
3 Results and discussion .................................. 282
3.1 Alteration in the mechanical performance of coals
in different stress states ......................... 282
3.2 The effect of the stress state on methane
emission kinetics from coals ....................... 285
3.3 The effect of moisture content on the mechanical
performance of coals ............................... 287
4 Conclusions ............................................. 291
22 Experimental study of wellbore deformation in a deep
claystone formation
Y. Lu, M. Chen, Y. Jin, P. Yang, Z. Xie, J. Yuan &
K. Fan ..................................................... 293
1 Introduction ............................................ 293
2 Preparation of the experimental apparatus ............... 294
3 Apparatus for measuring wellbore deformation and the
triaxial loading system ................................. 295
4 Analysis of testing results ............................. 296
5 Conclusions ............................................. 296
23 Triaxial loading system as a tool for solving
geotechnical problems of oil and gas production
V. Karev & Yu. Kovalenko ................................... 301
1 Study of the effect of stress-strain behavior on rock
permeability ............................................ 301
1.1 Description of the apparatus ....................... 301
1.2 Findings of the experimental study of the effect
of stress-strain behavior on the filtration
properties of rocks ................................ 305
2 Directional and horizontal wellbore stabilization ....... 307
3 Conclusions ............................................. 310
24 A true triaxial stress cell (TTSC) used for simulations
of real field operations in the lab
V. Rasouli ................................................. 311
1 Introduction ............................................ 311
2 Features of the TTSC .................................... 312
3 Experiment examples using the TTSC ...................... 313
3.1 Hydraulic fracturing ............................... 313
3.2 Sanding analysis ................................... 315
3.3 Fracture shear test ................................ 316
4 Conclusions ............................................. 318
Section 5: Miscellaneous
25 Fractographical analysis of the failure surfaces from
triaxial extension tests on Kimachi sandstone
Y. Fujii, N. Takahashi, M. Takahashi, Т. Takemura &
H. Park .................................................... 323
1 Introduction ............................................ 323
2 Test specimens and method ............................... 324
2.1 Geology of the Kimachi sandstone ................... 324
2.2 Testing method ..................................... 324
3 Test results ............................................ 324
4 Fracture surface measurement using digital
photogrammetry .......................................... 325
4.1 Digital photogrammetry ............................. 325
4.2 Application to fracture surfaces ................... 326
4.3 Shear fracture angle ............................... 327
4.4 Roughness of tensile fracture ...................... 327
5 Discussion .............................................. 328
5.1 Formation of shear fracture ........................ 328
5.2 Formation of tensile fracture ...................... 328
6 Summary and conclusions ................................. 329
26 Energy conversion and damage evolution of rocks under
cyclic loading conditions
R.D. Peng, Y. Ju, H. Xie & L.Y. Li ......................... 331
1 Introduction ............................................ 331
2 Thermodynamic analysis during rock deformation and
failure ................................................. 332
2.1 Energy conversion and thermodynamic state .......... 333
2.2 Rock damage and energy dissipation ................. 335
3 Testing program ......................................... 337
3.1 Rock samples and testing machine ................... 337
3.2 Loading procedure .................................. 337
4 Experimental results and discussion ..................... 338
4.1 Energy dissipation ................................. 338
4.2 Rigidity degradation ............................... 338
4.3 Damage evolution and failure criterion ............. 339
5 Conclusions ............................................. 340
27 Superbrittle failure regime of rocks at conventional
triaxial compression
B. Tarasov ................................................. 343
1 Introduction ............................................ 343
2 Brittleness variation with confining pressure for
rocks of different stiffness ............................ 344
3 Mechanism of rock embrittlement at high confining
pressure ................................................ 346
4 Conclusions ............................................. 349
28 Depth-dependent mechanical parameters of basalt: An
experimental study
H.W. Zhou, J.P. Zuo, D.J. Xue, H. Xie & J.F. Liu ........... 351
1 Introduction ............................................ 351
2 Description of laboratory experiments ................... 352
2.1 Sampling and sample preparation .................... 352
2.2 Testing system ..................................... 353
2.3 Experimental procedure ............................. 353
3 Experimental results and analysis ....................... 354
3.1 Uniaxial compression test results and analysis ..... 354
3.2 Brazilian test results and analysis ................ 356
3.3 Conventional triaxial compression test results
and analysis ....................................... 357
4 Conclusions ............................................. 360
Subject index ................................................. 363
Book series ................................................... 367
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