When dealing with rock in civil engineering, mining engineering and other engineering, the process by which the rock fails under load should be understood, so that safe structures can be built on and in the rock. However, there are many ways for loading rock and rock can have a variety of idiosyncracies. This reference book provides engineers and researchers with the essential knowledge for a clear understanding of the process of rock failure under different conditions. It contains an introductory chapter explaining the role of rock failure in engineering projects plus a summary of the theories governing rock failure and an explanation of the computer simulation method. It subsquently deals in detail with explaining, simulating and illustrating rock failure in laboratory and field. The concluding chapter discusses coupled modelling and the anticipated future directions for this type of computer simulation. An appendix describing the RFPA numerical model (Rock Failure Process Analysis program) is also included.
About the Authors
Chun'an Tang has a PhD in Mining Engineering and is a Professor at the School of Civil & Hydraulic Engineering at Dalian University of Technology in China. He is an advisor for design and stablity problem modelling in mining and civil rock engineeringand and Chairman of the China National Group of the International Society for Rock Mechanics.
John Hudson is emeritus professor at Imperial College, London and is active as an independant consultant for Rock Engineering Consultants. He has a PhD in Rock Mechanics and completed over a 130 rock engineering consulting assignments in mining and civil engineering. He is a fellow at the Royal Academy of Engineering in the UK and President of the International Society for Rock Mechanics.
John Hudson is emeritus professor at Imperial College, London and is active as an independant consultant for Rock Engineering Consultants. He has a PhD in Rock Mechanics and completed over a 130 rock engineering consulting assignments in mining and civil engineering. He is a fellow at the Royal Academy of Engineering in the UK and President of the International Society for Rock Mechanics. Chun'an Tang has a PhD in Mining Engineering and is a Professor at the School of Civil & Hydraulic Engineering at Dalian University of Technology in China. He is an advisor for design and stablity problem modelling in mining and civil rock engineeringand and Chairman of the China National Group of the International Society for Rock Mechanics.
Preface Acknowledgements About the authors List of figures List of tables Explanatory notes 1. Introduction 1.1 The purpose of this book 1.2 Why do things break? 1.3 Rock failure in geological and recent history 1.4 Rock failure in present day engineering 1.5 The nature of rock - a natural material 1.5.1 Discontinuities 1.5.2 Inhomogeneity 1.5.3 Anisotropy 1.5.4 Inelasticity 1.6 Numerical modelling of rock failure 1.7 The content of this book 2. Rock failure in uniaxial tension 2.1 Introduction 2.2 Specimen simulation 2.3 Numerical simulation results for the uniaxial tension case 2.4 Further studies of simulated rock failure in uniaxial tension 3. Rock failure in indirect tension 3.1 Generating a tensile stress through compressive loading 3.2 Establishing the numerical simulation model for indirect tensile strength tests 3.3 Numerical simulations of rock failure in indirect tensile strength tests 3.3.1 The disc test 220.127.116.11 Stress distribution in the discs 18.104.22.168 Effect of the material properties of theload-bearing strip on the disc test 22.214.171.124 Effect of load-bearing strip width on disc test 126.96.36.199 Effect of specimen size on the disc test 3.3.2 The plate test 3.3.3 The ring test 188.8.131.52 Stress distribution along the loadingdiameter for ring specimens 184.108.40.206 Effect of hole diameter on the failurepattern of ring specimens 220.127.116.11 Effect of hole diameter on the ringtest indirect tensile strength 4. Rock failure uniaxial compression 4.1 Introduction 4.2 Numerical illustrations of rock failure in uniaxial compression 4.2.1 Model description 4.2.2 Numerical simulation results 4.2.3 Summary of the numerical simulation observations 18.104.22.168 The complete stress-strain curve 22.214.171.124 Acoustic emission (AE) events and their locations 126.96.36.199 Stress distribution and failure-induced stress redistribution 4.3 Rock failure modes in uniaxial compression 4.4 Factors affecting rock failure behaviour 4.4.1 Model description 4.4.2 Effect of end constraint in terms of the Young's modulusof the loading platens 4.4.3 Effect of height to width ratio (slenderness)of the specimen 4.4.4 Class I and Class II curves in uniaxial compression 4.4.5 The size effect 5. Confinement and shear 5.1 The effect of confinement 5.2 Acoustic emission during shearing 5.3 Biaxial loading 6. Effect of heterogeneity on rock failure 6.1 Introduction 6.2 Heterogeneity-induced stress fluctuations 6.2.1 Discs subjected to diametral loading 6.2.2 Rock blocks under hydrostatic stress 6.3 Heterogeneity-related seismic patterns 6.4 Influence of heterogeneity on crack propagation modes 6.4.1 Numerical specimen 6.4.2 Numerical results and discussion 6.5 The influence of heterogeneity on the meso-scale 6.5.1 Digital image based modelling method 6.5.2 Numerical model based on the digital image 6.5.3 Simulation results for uniaxial compression 6.5.4 Influence of interface strength 7. The effect of rock anisotropy on rock failure 7.1 Introduction 7.2 Numerical models 8. Loading, unloading and the Kaiser Effect 8.1 Introduction 8.2 Numerical simulation 9. Time dependency of rock failure 9.1 Introduction 9.2 A constitutive model for the time-dependent behaviour of rocks 9.3 Illustrations of time-dependent micro-structural damage 9.3.1 The creep test 9.3.2 The relaxation test 9.4 Degradation of building stones with time 10. Coalescence of fractures 10.1 Introduction 10.2 Modelling of crack growth from crack-like flaws in compression 10.2.1 An angled crack-like flaw 10.2.2 Crack growth from an array of crack-like flaws 10.2.2.1 Wing crack growth from three array flaws 10.2.2.2 Wing crack growth from randomly distributed multi-flaws 10.3 Crack growth from a pore-like flaw in compression 10.3.1 Modelling crack growth from a single hole in specimens under compression 1 10.3.1.1 Crack growth from a single hole in specimens of different width 10.3.1.2 Crack growth from a single hole with different diameters 10.3.1.3 Modelling of crack growth from an array of holes in a specimen under compression 11. Dynamic loading of rock 11.1 Introduction 11.2 The simulation models 11.3 Simulation demonstration 11.3.1 Influence of heterogeneity on stress wave propagation 11.3.2 Influence of stress wave amplitude on the fracture process and failure pattern 12. Rock failure and water flow 12.1 Introduction 12.2 Rock failure under hydraulic pressure 12.3 Illustrations of fluid flow in heterogeneous initially intact rock 12.3.1 Evolution of flow paths 12.4 Comparison with the rock degradation modelling by Yuan and Harrison (2005) 12.5 Fluid flow in initially intact rock containing block in homogeneities 13. Rock failure induced by thermal stress 13.1 Introduction 13.2 Thermally-induced rock failure 13.3 Thermal cracking of a discring model 13.4 Thermal cracking in models containing irregularly shaped inclusions 14. Slope failure in rock masses 14.1 Introduction 14.2 Strength reduction rule and determination of safety factor 14.3 A slope in a layered rock mass 14.4 A slope in a jointed rock mass 14.5 A slope in a jointed rock mass with differing joint persistence 15. The fracture process when cutting inhomogeneous rocks 15.1 Introduction 15.2 Modelling rock cutting and the failure mechanism 15.2.1 Quasi-photoelastic fringe pattern 15.2.2 Fracture pattern 15.2.3 The chipping process 15.3 The load-displacement response when cutting in homogeneous rock 15.4 The crushed zone during rock cutting 16. Rock failure around tunnels in jointed rock 16.1 Introduction 16.2 Progressive failure around a tunnel in a jointed rock mass 16.2.1 Effect of dip angles on the stability of tunnel 16.2.2 The effect of the lateral stress on the mode of tunnel failure 16.2.3 Displacements at the tunnel periphery 17. Rock failure induced by longwall coal mining 17.1 Introduction 17.2 Illustrations of longwall mining simulations 17.3 The Daliuta coal mine in China 17.3.1 The strata failure process 17.3.2 Pillar stresses 18. Gas outbursts in coal mines 18.1 Introduction 18.2 Outbursts induced by cross-cutting from rock to coal seam 18.3 Outburst as the working face approaches high methanepressure in the coal seam 19. Particle breakage and comminution 19.1 Introduction 19.2 Single particle breakage 19.2.1 Breakage of single particle under diametral loading without confinement 19.2.2 Breakage of single particle under diametral loading with confinement 19.3 Multiple particle breakage 19.3.1 Fragmentation process of a rock particle assemblage in a container 19.3.2 Force and displacement relation duringthe breakage process 19.3.3 Energy considerations 19.3.4 Size distribution 19.3.5 Influence of particle shape 20. 3-D Modelling and `turtle crack formation' in rock 20.1 Introduction 20.2 The three-layer model 20.3 Fracture spacing measurements 21. Concluding remark References and bibliography Index Preface