Experimental Rock Deformation - The Brittle Field (eBook)

Preface 5
Contents 7
Introduction 11
Experimental Procedures 14
The Triaxial Test 14
Other Types of Tests 24
Experimental Studies on the Brittle Fracture Stress 26
Introduction 26
Types of Fractures 27
Observed Stresses at Brittle Failure 30
Influence of Strain Rate, Temperature, and Time 36
Size and Shape Effects 39
Influence of Intermediate Principal Stress 44
Anisotropy 47
Griffith Theory of Brittle Failure 54
Introduction 54
Uniaxial Tension 55
Uniaxial Compression and Biaxial Stresses 58
Triaxial Stresses 60
Modified Griffith Theory (Closed Cracks) 62
Extension of the Griffith Approach to Other Modes of Localized Inelastic Failure 64
General Comment on Griffith-Type Theories 65
Evolution of Physical Properties during Brittle Failure 67
Introduction 67
Pre-peak and Post-peak Behaviour 68
Volume Changes 76
Elastic Wave Speeds and Attenuation 84
Transport Properties 96
Acoustic Emission 101
Microscopical Observations 107
A Synoptic View of Brittle Failure 119
Micromechanics of Brittle Fracture 123
Introduction 123
Micromechanical Theory for Compact Rock 124
Micromechanical Theory for Porous Rock 142
Localization Theory 145
The Role of Pore Fluids 154
Introduction 154
The Notion of Effective Stress 155
Elastic Properties of Porous Media 156
Brittle Failure – Experimental 162
Brittle Failure – Theory of Pore Pressure Effects 168
Friction and Sliding Phenomena 171
Introduction 171
Coefficient of Friction 172
Phenomenology of Frictional Behaviour 179
Physical Aspects of Rock Friction 204
Brittle-Ductile Transition 216
Introduction 216
Experimental Observations 217
Physical Basis of the Brittle-Ductile Transition 227
Ductile to Brittle Transitions 238
Fracture Mechanics 243
Stress Intensity Analysis 243
Critical Parameters for Failure 246
Dynamic and Kinetic Effects 248
Plasticity Theory and Localization Analysis 251
Introduction 251
Constitutive Relations for a Material without Pressure Dependence or Dilatancy 252
Constitutive Model for Dilatant, Pressure-Sensitive Materials 254
Bifurcation, Instability and Shear Localization 258
Constitutive Relations for Friction 261
Introduction 261
Friction Law 262
Evolution Law 263
Time-Dependent Evolution during Stationery Contact 265
Analysis of Frictional Stability – Stick-Slip 266
Influence of Normal Stress and Temperature 267
References 270
Index 337