Mechanical behavior of rocks under high pressure conditions / Mitsuhiko Shimada.

Format:

Book

Author/Creator:

Shimada, Mitsuhiko.

Series:

Geomechanics research series 0929-4856 ; 2.

Geomechanics research series, 0929-4856 ; 2

Language:

English

Subjects (All):

Rock mechanics.

High pressure (Science).

Earthquake prediction.

Physical Description:

x, 178 pages : illustrations ; 26 cm.

Place of Publication:

Rotterdam ; Brookfield, Vt. : A. A. Balkema, 2000.

Summary:

Shimada (Research Center for Earthquake Prediction, Kyoto U., Japan) presents a survey of his and others' research into the mechanical behavior of rocks at high pressures and temperature. The emphasis here is on high confining and high uniaxial stress using a cubic press, which the author claims is a departure from the usual methods which focused solely on the behavior of rock in either the crust or the mantle (requiring different methods). He discusses two types of brittle fracture and their implications and looks at the mechanical behavior of porous silicate rocks. Annotation copyrighted by Book News, Inc., Portland, OR

Contents:

2 Triaxial Testing Under High Confining Pressures 4

2.2 Triaxial testing apparatus 6

2.2.1 Conventional apparatus 6

2.2.2 Solid-medium Griggs type apparatus 9

2.2.3 Cubic press 9

2.2.4 Ultra-high pressure apparatus 12

2.3 The method of triaxial testing in a cubic press 13

2.3.1 Apparatus and sample assembly 13

2.3.2 Experimental procedures at room temperature 16

2.3.3 Experimental procedures at high temperatures 19

Appendix 2.1 Pressure scale 22

Appendix 2.2 Observed examples of the effect of axial loading on confining pressure 23

3 Experimental Results on Low Porosity Silicate Rocks 25

3.1 Compressive strength 25

3.1.1 Pressure dependence of strength at moderate confining pressures 25

3.1.2 Pressure dependence of strength at high confining pressures 27

3.2 Acoustic emission 30

3.3 Frictional strength under high confining pressures 35

3.4 Fault features 38

3.4.1 Sample preparation 39

3.4.2 Features of faulting 39

Appendix 3.1 Stress-strain curves at room temperature 46

Appendix 3.2 Strength data at room temperature 47

4 Two Types of Brittle Fracture 51

4.1 High pressure type of fracture 51

4.1.1 Comparison with previous high temperature experiments 52

4.1.2 Transitional regime and semibrittle regime 55

4.2 Other examples of two types of fracture 57

4.2.1 Gneiss 57

4.2.2 Experiments in a cubic press at high temperatures 61

4.2.3 Temperature dependence of strength in the high-pressure type regime 68

4.3 Micromechanics 73

4.3.2 Micro-fracture styles 73

4.3.3 Discussion on the mechanisms of fracturing 79

Appendix 4.1 Strength data at elevated temperatures 84

5 Geophysical and Geological Implications of the Two Types of Fracture 86

5.1 The conditions for application to the earth's interior 86

5.2 The effect of size on rock strength under confining pressures 88

5.2.1 The effect of size on uniaxial compressive strength and characteristic length 88

5.2.2 The effect of size under confining pressure 90

5.2.3 Implications in the earth's crust 92

5.3 Strength of the lithosphere 96

5.3.1 Brittle-ductile model 96

5.3.2 A model including the high-pressure type fracture 98

5.4 An approach to earthquake prediction research 104

6 Mechanical Behavior of Porous Silicate Rocks 108

6.2 Mechanical properties of a porous basalt under high confining pressure 109

6.2.1 Volumetric strain 109

6.2.2 AE activity 112

6.2.3 Boundaries of mechanical states in the differential stress

confining pressure field 114

6.3 Microstructural observations of porous basalt and the mechanism of cataclastic ductile flow 117

6.3.1 Macroscopic observations 119

6.3.2 Microscopic observations 119

6.3.3 The mechanism of cataclastic ductile flow 127

6.4 Change in the mechanism of cataclastic flow of porous rock under high confining pressure 132

6.4.1 Creep analysis and equivalent viscosity 133

6.4.2 Pressure-induced change in the mechanism of cataclastic flow 138

6.5 High-pressure embrittlement 140

6.5.1 High-pressure embrittlement in porous sandstone 141

6.5.2 Microscopic observations of high-pressure embrittlement in eclogite 143

6.5.3 Conditions and mechanism of high-pressure embrittlement 145

6.6 Structure of a fault zone and related geophysical and geological implications 147

Appendix 6.1 Experimental data on the deformation of dry Yakuno basalt with 7% porosity at room temperature 150

Appendix 6.2 Characteristics of the cubic press with a large axial displacement 152.

ISBN:

9058093166

OCLC:

44697397