Rock Stress and Its Measurement

'...of great interest...' Australian Mineral Foundation Reviews

• 1 Introduction.- 1.1 Stress at a point.- 1.2 Importance of rock stress.- 1.3 History.- 1.4 Classification of rock stresses.- 1.5 Content of the book.- 1.6 General observations.- References.- 2 Estimating in situ stresses.- 2.1 Introduction.- 2.2 Variation of in situ stresses with depth.- 2.3 Vertical and horizontal stresses as principal stresses.- 2.4 Limits of in situ stresses with depth.- 2.5 Effect of anisotropy.- 2.6 Effect of stratification.- 2.7 Effect of geological structures and heterogeneities.- 2.8 Effect of topography.- 2.9 Tectonic and residual stresses.- 2.10 Effect of erosion, overconsolidation, uplift and glaciation.- 2.11 High horizontal stresses.- 2.12 Spherical shell models of stresses in the Earth.- 2.13 Effect of boundary conditions and time on in situ stress.- 2.14 Estimating stress orientation.- 2.15 Summary.- References.- 3 Methods of in situ stress measurement.- 3.1 Introduction.- 3.2 Hydraulic methods.- 3.3 Relief methods.- 3.4 Jacking methods.- 3.5 Strain recovery methods.- 3.6 Borehole breakout method.- 3.7 Other methods.- 3.8 Rock volume in stress measurements.- 3.9 Accuracy and uncertainty in stress measurements.- References.- 4 Hydraulic methods.- 4.1 Introduction.- 4.2 Hydraulic fracturing.- 4.3 Sleeve fracturing.- 4.4 HTPF.- 4.5 Integrated stress determination method.- 4.6 Technical information.- References.- 5 Relief methods.- 5.1 Introduction.- 5.2 History.- 5.3 Techniques, equipment and procedures.- 5.4 Theory.- 5.5 Statistical analysis of overcoring measurements.- 5.6 Effect of nonlinearity on overcoring results.- 5.7 Effect of anisotropy on overcoring results.- 5.8 Technical information.- References.- 6 Jacking methods.- 6.1 Introduction.- 6.2 History.- 6.3 Techniques, equipment and procedures.- 6.4 Theory.- 6.5 Technical information.- References.- 7 Strain recovery methods.- 7.1 Introduction.- 7.2 History.- 7.3 Techniques, equipment and procedures.- 7.4 Theory.- 7.5 Data analysis and interpretation.- References.- 8 Borehole breakout method.- 8.1 Introduction.- 8.2 History.- 8.3 Techniques, equipment and procedures.- 8.4 Theory.- 8.5 Data analysis and interpretation.- References.- 9 Case studies and comparison between different methods.- 9.1 Stress measurements at the URL project.- 9.2 Comparison between different overcoring techniques.- 9.3 Comparison between hydraulic fracturing and overcoring techniques.- 9.4 Comparison between hydraulic methods.- 9.5 Comparison between hydraulic fracturing and borehole breakout methods.- References.- 10 Monitoring of stress change.- 10.1 Introduction.- 10.2 Techniques and applications.- 10.3 Technical information.- References.- 11 The state of stress in the Earth’s crust: from local measurements to the World Stress Map.- 11.1 The World Stress Map.- 11.2 Effect of scale on in situ stresses: fact or fiction?.- References.- 12 Using stresses in rock engineering, geology and geophysics.- 12.1 Introduction.- 12.2 Stresses in civil rock engineering.- 12.3 Stresses in mining engineering.- 12.4 Stresses in geology and geophysics.- References.- Appendix A Analysis of stress.- A.1 Cauchy stress principle.- A.2 State of stress at a point.- A.3 State of stress on an inclined plane.- A.4 Force and moment equilibrium.- A.5 Stress transformation law.- A.6 Normal and shear stresses on an inclined plane.- A.7 Principal stresses.- Appendix B Displacements, stresses and strains around a circular hole: anisotropic solution.- B.1 General expressions for displacement components.- B.2 Expressions for displacement components when hole axis z is perpendicular to a plane of elasticsymmetry.- B.3 Radial displacement induced by drilling a hole in an infinite anisotropic medium.- B.5 Total radial displacement around the borehole contour.- B.6 General expressions for stress components.- B.7 Stresses around a circular hole drilled in an infinite anisotropic medium under a 3D state of stress acting at infinity.- B.8 Strain components.- Author index.