巖石材料尺度效應及破斷結(jié)構(gòu)效應(Scale-Size and Structural Effect

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