Contributors WJJ
About the authors JY
Preface YJ
Acknowledgments YJJJ
Size effect of rock samples 1
Hossein Masoumi
1.1 Size effect law for intact rock 2
1.1.1 Introduction 2
1.1.2 Background 3
1.1.3 Experimental study 9
1.1.4 Unified size effect law 19
1.1.5 Reverse size effects in UCS results 24
1.1.6 Contact area in size effects of point load results 28
1.1.7 Conclusions 34
1.2 Length-to-diameter ratio on point load strength index 35
1.2.1 Introduction 35
1.2.2 Background 36
1.2.3 Methodology 38
1.2.4 Valid and invalid failure modes 39
1.2.5 Conventional point load strength index size effect 42
1.2.6 Size effect of point load strength index 44
1.2.7 Conclusions 49
1.3 Plasticity model for size-dependent behavior 51
1.3.1 Introduction 51
1.3.2 Notation and unified size effect law 53
1.3.3 Bounding surface plasticity 55
1.3.4 Model ingredients 57
1.3.5 Model calibration 65
1.3.6 Conclusions 74
1.4 Scale-size dependency of intact rock 77
1.4.1 Introduction 77
1.4.2 Rock types 78
1.4.3 Experimental procedure 80
1.4.4 Comparative study 91
1.4.5 Conclusion 103
1.5 Scale effect into multiaxial failure criterion 103
1.5.1 Introduction 103
1.5.2 Background 106
J
JJ Contents
1.5.3 Scale and Weibull statistics into strength measurements 107
1.5.4 The modified failure criteria 111
1.5.5 Comparison with experimental data 117
1.5.6 Conclusions 121
1.6 Size-dependent Hoek-Brown failure criterion 121
1.6.1 Introduction 121
1.6.2 Background 122
1.6.3 Size-dependent Hoek-Brown failure criterion 126
1.6.4 Example of application 136
1.6.5 Conclusions 137
References 137
Further reading 144
Rock fracture toughness 145
Sheng Zhang
2.1 Fracture toughness of splitting disc specimens 146
2.1.1 Introduction 146
2.1.2 Preparation of disc specimens 147
2.1.3 Fracture toughness of five types of specimens 148
2.1.4 Load-displacement curve of disc splitting test 153
2.1.5 Comparison of disc splitting test results 155
2.1.6 Conclusions 158
2.2 Fracture toughness of HCFBD 159
2.2.1 Introduction 159
2.2.2 Test method and principle 160
2.2.3 HCFBD specimens with prefabricated cracks 162
2.2.4 Calibration of maximum dimensionless SIF Ymax 163
2.2.5 Results and analysis 164
2.2.6 Conclusions 168
2.3 Crack length on dynamic fracture toughness 169
2.3.1 Introduction 169
2.3.2 Dynamic impact splitting test 169
2.3.3 Results and discussion 171
2.3.4 DFT irrespective of configuration and size 175
2.3.5 Conclusions 176
2.4 Crack width on fracture toughness 177
2.4.1 Introduction 177
2.4.2 NSCB three-point flexural test 178
2.4.3 Width influence on prefabricated crack 180
2.4.4 Width influence of cracks on tested fracture toughness 183
2.4.5 Method for eliminating influence of crack width 185
2.4.6 Conclusions 187
2.5 Loading rate effect of fracture toughness 188
2.5.1 Introduction 188
2.5.2 Specimen preparation 189
2.5.3 Test process and data processing 189
Contents JJJ
2.5.4 Results and analysis 191
2.5.5 Conclusions 204
2.6 Hole influence on dynamic fracture toughness 204
2.6.1 Introduction 204
2.6.2 Dynamic cleaving specimens and equipment 205
2.6.3 SHPB test and data record 207
2.6.4 Dynamic finite element analysis 210
2.6.5 Results analysis and discussion 212
2.6.6 Conclusions 217
2.7 Dynamic fracture toughness of holed-cracked discs 217
2.7.1 Introduction 217
2.7.2 Dynamic fracture toughness test 219
2.7.3 Experimental recordings and results 221
2.7.4 Dynamic stress intensity factor in spatial-temporal
domain 226
2.7.5 Conclusions 231
2.8 Dynamic fracture propagation toughness of P-CCNBD 231
2.8.1 Introduction 231
2.8.2 Experimental preparation 233
2.8.3 Experimental recording and data processing 237
2.8.4 Numerical calculation of dynamic stress intensity factor 242
2.8.5 Determine dynamic fracture toughness 247
2.8.6 Conclusions 253
References 254
Further reading 258
Scale effect of the rock joint 259
Joung Oh
3.1 Fractal scale effect of opened joints 260
3.1.1 Introduction 260
3.1.2 Scale effect based on fractal method 262
3.1.3 Constitutive model for opened rock joints 266
3.1.4 Validation of proposed scaling relationships 268
3.1.5 Conclusions 272
3.2 Joint constitutive model for multiscale asperity degradation 274
3.2.1 Introduction 274
3.2.2 Quantification of irregular joint profile 275
3.2.3 Description of proposed model 277
3.2.4 Joint model validation 281
3.2.5 Conclusions 288
3.3 Shear model incorporating small- and large-scale irregularities 290
3.3.1 Introduction 290
3.3.2 Constitutive model for small-scale joints 291
3.3.3 Constitutive model for large-scale joints 294
3.3.4 Correlation with experimental data 299
3.3.5 Conclusions 308
JW Contents
3.4 Opening effect on joint shear behavior 309
3.4.1 Introduction 309
3.4.2 Constitutive model for joint opening effect 310
3.4.3 Opening model performance 312
3.4.4 Discussion 317
3.4.5 Conclusions 318
3.5 Dilation of saw-toothed rock joint 318
3.5.1 Introduction 318
3.5.2 Constitutive law for contacts in DEM 320
3.5.3 Model calibration 320
3.5.4 Direct shear test simulation 323
3.5.5 Conclusions 333
3.6 Joint mechanical behavior with opening values 334
3.6.1 Introduction 334
3.6.2 Normal deformation of opened joints 337
3.6.3 Direct shear tests 350
3.6.4 Results analysis and discussion 351
3.6.5 Conclusions 356
3.7 Joint constitutive model correlation with field observations 357
3.7.1 Introduction 357
3.7.2 Model description and implementation 358
3.7.3 Stability analysis of large-scale rock structures 365
3.7.4 Conclusions 385
References 390
Further reading 397
Microseismic monitoring and application 399
Shuren Wang and Xiangxin Liu
4.1 Acoustic emission of rock plate instability 400
4.1.1 Introduction 400
4.1.2 Materials and methods 401
4.1.3 Results analysis 405
4.1.4 Discussion of the magnitudes of AE events 407
4.1.5 Conclusions 408
4.2 Prediction method of rockburst 409
4.2.1 Introduction 409
4.2.2 Microseismic monitoring system 410
4.2.3 Active microseismicity and faults 412
4.2.4 Rockburst prediction indicators 415
4.2.5 Conclusions 420
4.3 Near-fault mining-induced microseismic 420
4.3.1 Introduction 420
4.3.2 Engineering situations 422
4.3.3 Computational model 424
4.3.4 Result analysis and discussion 425
4.3.5 Conclusions 430
Contents W
4.4 Acoustic emission recognition of different rocks 432
4.4.1 Introduction 432
4.4.2 Experiment preparation and methods 434
4.4.3 Results and discussion 439
4.4.4 AE signal recognition using ANN 442
4.4.5 Conclusions 448
4.5 Acoustic emission in tunnels 448
4.5.1 Introduction 448
4.5.2 Rockburst experiments in a tunnel 450
4.5.3 Experimental results 453
4.5.4 AE characteristics of rockburst 458
4.5.5 Discussion 461
4.5.6 Conclusions 466
4.6 AE and infrared monitoring in tunnels 466
4.6.1 Introduction 466
4.6.2 Simulating rockbursts in a tunnel 468
4.6.3 Experimental results 471
4.6.4 Rockburst characteristics in tunnels 482
4.6.5 Conclusions 485
References 486
Further reading 493
Structural effect of rock blocks 495
Shuren Wang and Wenbing Guo
5.1 Cracked roof rock beams 496
5.1.1 Introduction 496
5.1.2 Mechanical model of a cracked roof beam 497
5.1.3 Instability feature of cracked roof beams 505
5.1.4 Mechanical analysis of roof rock beams 507
5.1.5 Conclusions 512
5.2 Evolution characteristics of fractured strata structures 512
5.2.1 Introduction 512
5.2.2 Engineering background 515
5.2.3 Mechanical and computational model 517
5.2.4 Results and discussion 521
5.2.5 Conclusions 531
5.3 Pressure arching characteristics in roof blocks 532
5.3.1 Introduction 532
5.3.2 Pressure arching characteristics 534
5.3.3 Evolution characteristics of pressure arch 541
5.3.4 Results and discussion 546
5.3.5 Conclusions 549
5.4 Composite pressure arch in thin bedrock 550
5.4.1 Introduction 550
5.4.2 Engineering background and pressure arch structure 551
5.4.3 Computational model and similar experiment 557
WJ Contents
5.4.4 Results and discussion 560
5.4.5 Conclusions 568
5.5 Pressure arch performances in thick bedrock 569
5.5.1 Introduction 569
5.5.2 Engineering background 571
5.5.3 Pressure-arch analysis and experimental methods 572
5.5.4 Results and discussion 577
5.5.5 Conclusions 586
5.6 Elastic energy of pressure arch evolution 587
5.6.1 Introduction 587
5.6.2 Engineering background 589
5.6.3 Pressure-arch analysis and computational model 591
5.6.4 Simulation results and discussion 594
5.6.5 Conclusions 604
5.7 Height predicting of water-conducting zone 605
5.7.1 Introduction 605
5.7.2 High-intensity mining in China 606
5.7.3 OFT influence on FWCZ development 608
5.7.4 Development mechanism of FWCZ based on OFT 611
5.7.5 Example analysis and numerical simulation 613
5.7.6 Engineering analogy 624
5.7.7 Conclusions 627
References 627
Further reading 633
Index 635
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