Engineering Rock Mechanics (eBook)

Front Cover 1
Engineering rock mechanics: an introduction to the principles 4
Copyright Page 5
Contents 8
Preface 12
Chapter 1. Introduction 14
1.1 The subject of rock mechanics 14
1.2 Content of this book 22
Chapter 2. Geological setting 24
2.1 Rock as an engineering material 24
2.2 Natural rock environments 27
2.3 The influence of geological factors on rocks and rock masses 29
Chapter 3. Stress 44
3.1 Why study stress in rock mechanics and rock engineering? 44
3.2 The difference between a scalar, a vector and a tensor 45
3.3 Normal stress components and shear stress components 45
3.4 Stress as a point property 46
3.5 The stress components on a small cube within the rock 47
3.6 The symmetry of the stress matrix 49
3.7 The state of stress at a point has six independent components 50
3.8 The principal stresses 50
3.9 All unsupported excavation surfaces are principal stress planes 51
3.10 Concluding remarks 53
Chapter 4. In situ stress 54
4.1 Why determine in situ stress? 54
4.2 Presentation of in situ stress state data 54
4.3 Methods of stress determination 55
4.4 Statistical analysis of stress state data 65
4.5 The representative elemental volume for stress 67
4.6 Predictions of natural in situ stress states based on elasticity theory 69
4.7 Collated worldwide in situ stress data 72
4.8 Reasons for high horizontal stresses 75
4.9 Effect of discontinuities on the proximate state of stress 78
4.10 Glossary of terms related to stress states in rock masses 81
Chapter 5. Strain 84
5.1 Finite strain 84
5.2 Examples of homogeneous finite strain 86
5.3 Infinitesimal strain 88
5.4 The strain tensor 90
5.5 The elastic compliance matrix 91
5.6 Implications for in situ stress 95
Chapter 6. Intact rock 98
6.1 The background to intact rock testing 98
6.2 The complete stress–strain curve in uniaxial compression 99
6.3 Soft, stiff and servo-controlled testing machines 102
6.4 Specimen geometry, loading conditions and environmental effects 108
6.5 Failure criteria 119
6.6 Concluding remarks 124
Chapter 7. Discontinuities 126
7.1 The occurrence of discontinuities 127
7.2 Geometrical properties of discontinuities 129
7.3 Mechanical properties 147
7.4 Discussion 151
Chapter 8. Rock masses 154
8.1 Deformability 154
8.2 Strength 157
8.3 Post-peak strength behaviour 160
Chapter 9. Permeability 162
9.1 Fundamental definitions 162
9.2 Primary and secondary permeability 164
9.3 Flow through discontinuities 164
9.4 Flow through discontinuity networks 167
9.5 Scale effect 169
9.6 A note on effective stresses 172
9.7 Some practical aspects: grouting and blasting 173
Chapter 10. Anisotropy and inhomogeneity 176
10.1 Definitions 176
10.2 Anisotropy 178
10.3 Inhomogeneity 179
10.4 Ramifications for analysis 182
Chapter 11. Testing techniques 186
11.1 Access to the rock 186
11.2 Tailoring testing to engineering requirements 187
11.3 Tests on intact rock 190
11.4 Tests on discontinuities 194
11.5 Tests on rock masses 199
11.6 Standardized tests 204
Chapter 12. Rock mass classification 206
12.1 Rock Mass Rating (RMR) system 206
12.2 Q-system 208
12.3 Applications of rock mass classification systems 211
12.4 Links between the classification systems and rock properties 214
12.5 Discussion 214
12.6 Extensions to rock mass classification techniques 215
12.7 Concluding remarks 219
Chapter 13. Rock dynamics and time-dependent aspects 220
13.1 Introduction 220
13.2 Stress waves 221
13.3 Time-dependency 226
13.4 Time-dependency in rock engineering 234
Chapter 14. Rock mechanics interactions and rock engineering systems (RES) 236
14.1 Introduction to the subject 236
14.2 Interaction matrices 238
14.3 Interaction matrices in rock mechanics 241
14.4 Symmetry of interaction matrices 242
14.5 A rock mechanics–rock engineering interaction matrix 245
14.6 Further examples of rock mechanics interaction matrices 248
14.7 Concluding remarks 249
Chapter 15. Excavation principles 252
15.1 The excavation process 252
15.2 Rock blasting 256
15.3 Specialized blasting techniques 261
15.4 Mechanical excavation 268
15.5 Vibrations due to excavation 274
Chapter 16. Stabilization principles 280
16.1 The effect of excavation on the rock mass environment 280
16.2 The stabilization strategy 282
16.3 Rock reinforcement 284
16.4 Rock support 287
16.5 Stabilization of 'transitional' rock masses 292
16.6 Further comments on rock stabilization methods 295
Chapter 17. Surface excavation instability mechanisms 300
17.1 Slope instability 300
17.2 Foundation instability 311
Chapter 18. Design and analysis of surface excavations 322
18.1 Kinematic analysis of slope instability mechanisms 322
18.2 Combined kinematic analysis of complete excavations 336
18.3 Foundations: stress distributions beneath variably loaded areas 338
18.4 Techniques for incorporating variations in rock and site factors into the analyses 343
Chapter 19. Underground excavation instability mechanisms 352
19.1 Structurally-controlled instability mechanisms 352
19.2 Stress-controlled instability mechanisms 359
19.3 A note on time-dependency and weathering 372
Chapter 20. Design and analysis of underground excavations 374
20.1 Design against structurally-controlled instability 374
20.2 Design against stress-controlled instability 387
20.3 Integrated design procedures 405
References 406
Appendix A: Stress and strain analysis 412
Appendix B: Hemispherical projection 444
Index 454