Engineering Rock Mass Classification

by Singh, Bhawani; Goel, R. K.

• ISBN13: 9780123858788
• ISBN10: 012385878X
• Format: Hardcover
• Copyright: 2011-07-05
• Publisher: Butterworth-Heinemann

Summary

Rock mass classification methods are commonly used at the preliminary design stages of a construction project when there is very little information. It forms the bases for design and estimation of the required amount and type of rock support and groundwater control measures. Encompassing nearly all aspects of rock mass classifications in detail, Civil Engineering Rock Mass Classification: Tunnelling, Foundations and Landsides provides construction engineers and managers with extensive practical knowledge which is time-tested in the projects in Himalaya and other parts of the world in complex geological conditions. Rock mass classification is an essential element of feasibility studies for any near surface construction project prior to any excavation or disturbances made to earth. Written by an author team with over 50 years of experience in some of the most difficult mining regions of the world, Civil Engineering Rock Mass Classification: Tunnelling, Foundations and Landsides provides construction engineers, construction managers and mining engineers with the tools and methods to gather geotechnical data, either from rock cuts, drifts or core, and process the information for subsequent analysis. The goal is to use effective mapping techniques to obtain data can be used as input for any of the established rock classification systems. The book covers all of the commonly used classification methods including: Barton's Q and Q' systems, Bieniawski's RMR, Laubscher's MRMR and Hoek's and GSI systems. With this book in hand, engineers will be able to gather geotechnical data, either from rock cuts, drifts or core, and process the information for subsequent analysis. Rich with international case studies and worked out equations, the focus of the book is on the practical gathering information for purposes of analysis and design. Identify the most significant parameters influencing the behaviour of a rock mass. Divide a particular rock mass formulation into groups of similar behaviour, rock mass classes of varying quality. Provide a basis of understanding the characteristics of each rock mass class Relate the experience of rock conditions at one site to the conditions and experience encountered at others Derive quantitative data and guidelines for engineering design Provide common basis for communication between engineers and geologists

Table of Contents

Preface	p. xiii
Acknowledgments	p. xv
Philosophy of Engineering Classifications	p. 1
The Classification	p. 1
Philosophy of Classification System	p. 2
Need for Engineering Geological Map	p. 2
Management of Uncertainties	p. 3
Present-Day Practice	p. 3
Scope of the Book	p. 4
Shear Zone Treatment in Tunnels and Foundations	p. 7
Shear Zone	p. 7
Treatment for Tunnels	p. 7
Treatment for Dam Foundations	p. 9
Rock Material	p. 13
Rock Material	p. 13
Homogeneity and Inhomogeneity	p. 13
Classification of Rock Material	p. 13
Class I and II Brittle Rocks	p. 15
Uniaxial Compression	p. 15
Stability in Water	p. 17
Classification on the Basis of Slake Durability Index	p. 18
Rock Quality Designation	p. 21
Rock Quality Designation	p. 21
Direct Method	p. 21
Indirect Methods	p. 23
Weighted Joint Density	p. 24
Red-Flag Effect of Low RQD	p. 29
Application of RQD	p. 30
Terzaghi's Rock Load Theory	p. 33
Introduction	p. 33
Rock Classes	p. 33
Rock Load Factor	p. 33
Modified Terzaghi's Theory for Tunnels and Caverns	p. 42
Rock Mass Rating	p. 45
Introduction	p. 45
Collection of Field Data	p. 45
Estimation of RMR	p. 50
Applications of RMR	p. 52
Precautions	p. 55
Rock Mass Excavability Index for TBM	p. 58
Tunnel Alignment	p. 60
Tunneling Hazards	p. 63
Introduction	p. 63
Tunneling Conditions	p. 65
Empirical Approach for Predicting Ground Conditions	p. 74
Theoretical/Analytical Approach	p. 78
Effect of Thickness of Weak Band on Squeezing Ground Condition	p. 80
Sudden Flooding of Tunnels	p. 80
Chimney Formation	p. 80
Environmental Hazards due to Toxic or Explosive Gases and Geothermal Gradient	p. 83
Conciuding Remarks	p. 83
Rock Mass Quality Q-System	p. 85
The Q-System	p. 85
Joint Orientation and the Q-System	p. 93
Updating the Q-System	p. 93
Collection of Field Data	p. 93
Classification of the Rock Mass	p. 94
Estimation of Support Pressure	p. 96
Estimation of Deformation or Closure	p. 101
Unsupported Span	p. 102
Design of Supports	p. 103
New Austrian Tunneling Method	p. 104
Norwegian Method of Tunneling	p. 106
Rock Mass Characterization	p. 106
Drainage Measures	p. 112
Experiences in Poor Rock Conditions	p. 113
Concluding Remarks	p. 113
Rock Mass Number	p. 119
Introduction	p. 119
Interrelation Between Q and RMR	p. 120
Prediction of Ground Conditions	p. 123
Prediction of Support Pressure	p. 123
Effect of Tunnel Size on Support Pressure	p. 123
Correlations for Estimating Tunnel Closure	p. 126
Effect of Tunnel Depth on Support Pressure and Closure in Tunnels	p. 127
Approach for Obtaining Ground Reaction Curve	p. 127
Coefficient of Volumetric Expansion of Failed Rock Mass	p. 129
Rock Mass Index	p. 133
Introduction	p. 133
Selection of Parameters used in RMi	p. 133
Calibration of RMi from Known Rock Mass Strength Data	p. 134
Scale Effect	p. 137
Examples (Palmstrom, 1995)	p. 140
Applications of RMi	p. 141
Benefits of Using RMi	p. 141
Limitations of RMi	p. 142
Rate of Tunneling	p. 145
Introduction	p. 145
Classification of Ground/Job Conditions for Rate of Tunneling	p. 146
Classification of Management Conditions for Rate of Tunneling	p. 146
Combined Effect of Ground and Management Conditions ton Rate of Tunneling	p. 153
Tunnel Management (Singh, 1993)	p. 154
Poor Tender Specifications	p. 155
Contracting Practice	p. 156
Quality Management by International Tunneling Association	p. 156
Support System in Caverns	p. 159
Support Pressure	p. 159
Wall Support in Caverns	p. 160
Roof Support in Caverns	p. 162
Stress Distribution in Caverns	p. 163
Opening of Discontinuities in Roof Due to Tensile Stress	p. 164
Rock Reinforcement Near Intersections	p. 164
Radial Displacements	p. 164
Precautions	p. 164
Strength Enhancement of Rock Mass in Tunnels	p. 169
Causes of Strength Enhancement	p. 169
Effect of Intermediate Principal Stress on Tangential Stress at Failure in Tunnels	p. 169
Uniaxial Compressive Strength of Rock Mass	p. 172
Reason for Strength Enhancement in Tunnels and a New Failure Theory	p. 173
Critical Strain of Rock Mass	p. 177
Criterion for Squeezing Ground Condition	p. 178
Rock Burst in Brittle Rocks	p. 178
Tensile Strength Across Discontinuous Joints	p. 180
Dynamic Strength of Rock Mass	p. 181
Residual Strength Parameters	p. 181
Rock Mass Quality for Open Tunnel Boring Machines	p. 185
Introduction	p. 185
Q and QTBM	p. 186
Penetration and Advance Rates	p. 188
Cutter Wear	p. 189
Penetration and Advance Rates versus QTBM	p. 189
Estimating Time for Completion	p. 190
Risk Management	p. 190
Strength of Discontinuities	p. 193
Introduction	p. 193
Joint Wall Roughness Coefficient	p. 193
Joint Wall Compressive Strength	p. 196
Joint Matching Coefficient	p. 198
Residual Angle of Friction	p. 198
Shear Strength of Joints	p. 200
Dynamic Shear Strength of Rough Rock Joints	p. 201
Theory of Shear Strength at Very High Confining Stress	p. 202
Normal and Shear Stiffness of Rock Joints	p. 203
Shear Strength of Rock Masses in Slopes	p. 205
Mohr-Coulomb Strength Parameters	p. 205
Non-Linear Failure Envelopes for Rock Masses	p. 205
Strength of Rock Masses in Slopes	p. 209
Back Analysis of Distressed Slopes	p. 210
Types of Failures of Rock and Soil Slopes	p. 211
Introduction	p. 211
Planar (Translational) Failure	p. 211
3D Wedge Failure	p. 211
Circular (Rotational) Failure	p. 211
Toppling Failure (Topples)	p. 213
Ravelling Slopes (Falls)	p. 214
Effect of Slope Height and Groundwater Conditions on Safe Slope Angle	p. 214
A Basic Landslide Classification System	p. 216
Causative Classification	p. 217
Comprehensive Classification System of Landslides	p. 217
Landslide in Over-Consolidated Clays	p. 217
Rock Slope Failures	p. 224
Landslide Dams	p. 229
Slope Mass Rating	p. 231
The Slope Mass Rating	p. 231
Slope Stability Classes	p. 234
Support Measures	p. 235
Modified SMR Approach	p. 236
Case Study of Stability Analysis using Modified SMR Approach	p. 238
Portal and Cut Slopes	p. 238
Landslide Hazard Zonation	p. 245
Introduction	p. 245
Landslide Hazard Zonation Maps-The Methodology	p. 246
A Case History (Gupta and Anbalagan, 1995)	p. 251
Proposition for Tea Gardens	p. 262
Geographic Information System	p. 262
Mega-Regional Landslide Zonation	p. 264
Allowable Bearing Pressure for Shallow Foundations	p. 267
Introduction	p. 267
A Classification for Net Safe Bearing Pressure	p. 267
Allowable Bearing Pressure	p. 269
Coefficient of Elastic Uniform Compression for Machine Foundations	p. 273
Scour Depth Around Bridge Piers	p. 273
Rock Parameters to Select Type of Dam	p. 274
Method of Excavation	p. 281
Excavation Techniques	p. 281
Assessing the Rippability	p. 281
Rock Mass Classification According to Ease of Ripping	p. 282
Empirical Methods in Blasting	p. 284
Rock Drillability	p. 287
Drillability and Affecting Parameters	p. 287
Classification for Drilling Condition	p. 288
Other Approaches	p. 291
Permeability and Groutability	p. 293
Permeability	p. 293
Permeability of Various Rock Types	p. 293
Permeability for Classifying Rock Masses	p. 295
Permeability versus Grouting	p. 295
Determination of Permeability	p. 295
Grouting	p. 296
Gouge Material	p. 307
Gouge	p. 307
Shear Strength of Filled Discontinuities (Silty to Clayey Gouge)	p. 310
Dynamic Strength	p. 311
Engineering Properties of Hard Rock Masses	p. 313
Hard Rock Masses	p. 313
Modulus of Deformation	p. 313
UCS	p. 314
Uniaxial Tensile Strength	p. 314
Strength Criterion	p. 314
Support Pressure in Non-Squeezing/Non-Rock Burst Conditions (H <350 Q1/3)	p. 315
Half-Tunnels	p. 315
Geological Strength Index	p. 319
Geological Strength Index	p. 319
Generalized Strength Criterion	p. 323
Mohr-Coulomb Strength Parameters	p. 326
Modulus of Deformation	p. 327
Rock Parameters for Intact Schistose	p. 329
Estimation of Residual Strength of Rock Masses	p. 329
Classification of Squeezing Ground Condition	p. 330
Evaluation of Critical Rock Parametere	p. 335
Introduction	p. 335
Critical Parameters	p. 335
Parameter Intensity and Dominance	p. 336
Classification of Rock Mass	p. 338
Example for Studying Parameter Dominance in Underground Excavation for a Coal Mine with a Flat Roof	p. 338
Relative importance of Rock Parameters in Major Projecte	p. 340
Interaction between Rock Parameters	p. 340
Application in Entropy Management	p. 344
In Situ Stresses	p. 345
The Need for In Situ Stress Measurement	p. 345
Classification of Geological Conditions and Stress Regimes	p. 345
Variation of In Situ Stresses with Depth	p. 347
Effect of in Situ Stress on Rock Mass Properties	p. 349
Core Discing	p. 349
Shear and Normal Stiffness of Rock Joints	p. 351
Bond Shear Strength of Grouted Bolts	p. 355
Index	p. 357
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