Contents
Chapter 1 Introduction1
1.1 Rock Fracture Mechanics 1
1.2 Cohesive Zone Model 2
1.3 Fracture Initiation and Propagation under Compression 5
1.4 Experimental Characterizations of Rock Fracture 7
1.4.1 Three-Point Bending 7
1.4.2 Uniaxial Compression 9
Chapter 2 Image Tracking Techniques 12
2.1 Historical Development 12
2.2 Digital Image Correlation 12
2.2.1 Basics of DIC 15
2.2.2 Matching Approaches of DIC 19
2.3 Particle Image Velocimetry 19
2.3.1 Basics of PIV 21
2.3.2 Matching Approaches of PIV 23
2.4 Differences between DIC and PIV 23
2.5 Practical Considerations 24
2.6 Specimen Preparation and DIC System Calibration 26
2.6.1 Speckle Pattern Preparation 26
2.6.2 DIC System Calibration 28
Chapter 3 Rock Fracture Initiation and Propagation under Different Loading Conditions 34
3.1 Testing Material�� Loading and Imaging Systems 34
3.1.1 Berea Sandstone and Specimen Geometry 34
3.1.2 Loading�� Controlling and Imaging Systems 35
3.2 Rock Fracture Initiation and Propagation under Mode I Loading 36
3.2.1 Theoretical Interpretation 36
3.2.2 Smooth Boundary Specimens 41
3.2.3 Center Notch Specimens 61
3.2.4 Specimens with Large Radius Notch 72
3.2.5 Discussion 80
3.3 Rock Fracture Initiation and Propagation under Mixed-mode Loading 83
3.3.1 Testing Methods 85
3.3.2 Specimen Geometry 86
3.3.3 Eccentric Notch Specimens-20% Position 87
3.3.4 Eccentric Notch Specimens-30% Position 95
3.3.5 Eccentric Notch Specimens-40% Position 99
3.3.6 Summary 102
Chapter 4 Influence of Flaw on Rock Fracturing under Compression 104
4.1 Introduction 104
4.2 The Extended Digital Image Correlation Method 106
4.2.1 XDIC Method 108
4.2.2 Parametric Sensitivity Analysis 111
4.3 Experimental Study on Cracking Behaviors from A Flaw without Filler 113
4.3.1 Rock Specimens 113
4.3.2 Rock-like Specimens 131
4.4 Experimental Study on Cracking Behaviors from A Flaw with Filler 147
4.4.1 Specimen Preparation 147
4.4.2 Specimen Testing 150
4.4.3 Experimental Results 150
4.4.4 Summary 169
4.5 Discussion 169
4.6 Conclusion 171
Chapter 5 Applications 173
5.1 Thermal Effect on Fracture Behavior of Beishan Granite 173
5.1.1 Engineering Background 173
5.1.2 Specimen Preparation and Testing Procedure 173
5.1.3 Mechanical Test Results 175
5.1.4 Thermal Effect on Fracture Initiation 176
5.1.5 Thermal Effect on the FPZ Size 178
5.1.6 Thermal Effect on the Critical Opening Displacement 181
5.1.7 Thermal Effect on Fracture Toughness Measurement 182
5.1.8Thermal Damage Mechanism in Beishan Granite 185
5.1.9Conclusions 187
5.2 Cyclic Thermal Shock Effect on Surface Crack 187
5.2.1 Engineering Background 187
5.2.2 Experimental Design of Cyclic Thermal Shock 189
5.2.3Surface and Internal Zones 191
5.2.4Crack Characteristics of Surface Zone 194
5.2.5 Quantitative Description of Deterioration Degree of Surface Zone Based on Cohesive Zone odel 201
5.2.6Conclusions 207
Chapter 6 Concluding Remarks 209
References 211
Figure 225