Page 13 - Engineering Rock Mass Classification_ Tunnelling, Foundations and Landslides

xii Contents

24. Gouge Material 307

Gouge 307
Shear Strength of Filled Discontinuities (Silty to Clayey Gouge) 310
Dynamic Strength 311

25. Engineering Properties of Hard Rock Masses 313

Hard Rock Masses 313
Modulus of Deformation 313
UCS 314
Uniaxial Tensile Strength 314
Strength Criterion 314
Support Pressure in Non-Squeezing/Non-Rock Burst Conditions
315
(H <350 Q1/3) 315
Half-Tunnels
319
26. Geological Strength Index
319
Geological Strength Index 323
Generalized Strength Criterion 326
Mohr-Coulomb Strength Parameters 327
Modulus of Deformation 329
Rock Parameters for Intact Schistose 329
Estimation of Residual Strength of Rock Masses 330
Classification of Squeezing Ground Condition
335
27. Evaluation of Critical Rock Parameters
335
Introduction 335
Critical Parameters 336
Parameter Intensity and Dominance 338
Classification of Rock Mass
Example for Studying Parameter Dominance in Underground 338
340
Excavation for a Coal Mine with a Flat Roof 340
Relative Importance of Rock Parameters in Major Projects 344
Interaction between Rock Parameters
Application in Entropy Management 345

28. In Situ Stresses 345
345
The Need for In Situ Stress Measurement 347
Classification of Geological Conditions and Stress Regimes 349
Variation of In Situ Stresses with Depth 349
Effect of In Situ Stress on Rock Mass Properties
Core Discing 351
355
Appendix I Shear and Normal Stiffness of Rock Joints 357
Appendix II Bond Shear Strength of Grouted Bolts
Index