A Tectonophysical Study of the Initiation and Development of Fracture in Rocks (Mineral Veins, Volcanic Dikes and Earthquake Faults), Thesis, University of Tokyo, 1968
Hitoshi Koide (1968) A Tectonophysical Study of the Initiation and Development of Fracture in Roc... more Hitoshi Koide (1968) A Tectonophysical Study of the Initiation and Development of Fracture in Rocks (Mineral Veins, Volcanic Dikes and Earthquake Faults), Part 1: Microcracks and Fault Development in Underground Rocks (Deformation Experiments under Confining Pressures), p.1-p.198, Part 2: Inclusion Model of Fractures and Fault Development in Underground Rocks with Full Exact Elastic Solution of Three Dimensional Stress Concentration around a Spheroidal Inclusion and Cavity (Theory and Field Study), p.199-p.399, Thesis, Doctor of Engineering, University of Tokyo
Table of contents
Summary
1. Introduction
2. Experimental deformation of rocks under confining pressures
3. Microscopic observation of fractures in rocks deformed under confining pressures
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4. Initiation and process of development of fractures
5. Patterns of fractures in rocks and earthquake faulting
6. Preferred orientation of fracture in rocks and ancient stress state
7. Conclusion
References
Table of contents
Summary
1. Introduction
2. Experimental deformation of rocks under confining pressures
3. Microscopic observation of fractures in rocks deformed under confining pressures
The Griffith inclusion model of fault, the effective stress control of hydraulic fracturing and the Coulomb failure stress on fault are discussed to analyze the mechanism of induced earthquakes. The “man-made” induced earthquake is actually an artificially accelerated natural earthquake. The geological and geophysical survey of natural critical faults, estimation of underground stress state, properties of underground rocks and investigation of underground fluids and groundwater regime are important to minimize the risk of induced seismicity.
The purpose of the IGC Workshop WC - 1 is to bring together geologists who are experts of waste disposal problems and participated in the 29th IGC from the worid and to have discussion with Japanese experts, mainly non-geologists who have not participated in the main congress. The workshop high-lighted the increasing role of geoiogists in the geological disposal of waste but also the importance of collaboration among many different groups of scientists and technologists.
This volume is the proceedings of the IGC Workshop WC - 1 and contains fuIl text of presentend papers and records of discussion sessions. The papers and discussions cover a diversity of topics and should provide the reader with a fairly broad perspective on the waste disposal problems that should be solved for human survival.
The results of experiments were tabulated in Table 4, The mechanical properties of sedimentary rocks have a wide range of value and are much influenced by lithological and geological factors. We tried to find relations among strength, confining pressure, deformational behavior, angle of fracture, strain at fracturing, failure type, porosity, grain size, axial shortening, sampled depth, elastic wave velocity, geologic age, stratigraphic level and tectonic environment. The mode of deformation, angle of fracture, and strain at fracturing are related to the ratio of shearing stress to normal stress on the plane of fracture or to the ratio of the maximum strength to the confining pressure. The failure type corresponds alrnost to the deformational behavior, and the change among failure types seems to be continuous. The " visco-ductile " flow is observed in extreme porous rocks, possibly because the framework is crushed by higher pressure than formerly applied. The strength of sedimentary rocks increases with diminution of porosity. Because of compaction, the rocks become, generally, stronger and less ductile with the sampled depth and with geologic age. The degree and effect of compaction, however, are much influenced by the lithofacies and tectonic history, The degree of strengthening with geologic age is the greatest in argillaceous rocks, greater in arenaceous rocks and less in pyroclastic rocks. Among six areas studied, there exists an interesting contrast in deformational behavior and strength. The rocks in Joban and Miura districts are much more ductile and weaker than rocks in the other areas. The confining pressure of ductile -to- visco-ductile transition and degree of strengthening with geologic age, too, suggest that very lower compressive stress has been applied on the rocks in Joban and Miura districts than in the other areas.
Papers by Hitoshi Koide
4. Initiation and process of development of fractures
5. Patterns of fractures in rocks and earthquake faulting
6. Preferred orientation of fracture in rocks and ancient stress state
7. Conclusion
References
Table of contents
Summary
1. Introduction
2. Experimental deformation of rocks under confining pressures
3. Microscopic observation of fractures in rocks deformed under confining pressures
The Griffith inclusion model of fault, the effective stress control of hydraulic fracturing and the Coulomb failure stress on fault are discussed to analyze the mechanism of induced earthquakes. The “man-made” induced earthquake is actually an artificially accelerated natural earthquake. The geological and geophysical survey of natural critical faults, estimation of underground stress state, properties of underground rocks and investigation of underground fluids and groundwater regime are important to minimize the risk of induced seismicity.
The purpose of the IGC Workshop WC - 1 is to bring together geologists who are experts of waste disposal problems and participated in the 29th IGC from the worid and to have discussion with Japanese experts, mainly non-geologists who have not participated in the main congress. The workshop high-lighted the increasing role of geoiogists in the geological disposal of waste but also the importance of collaboration among many different groups of scientists and technologists.
This volume is the proceedings of the IGC Workshop WC - 1 and contains fuIl text of presentend papers and records of discussion sessions. The papers and discussions cover a diversity of topics and should provide the reader with a fairly broad perspective on the waste disposal problems that should be solved for human survival.
The results of experiments were tabulated in Table 4, The mechanical properties of sedimentary rocks have a wide range of value and are much influenced by lithological and geological factors. We tried to find relations among strength, confining pressure, deformational behavior, angle of fracture, strain at fracturing, failure type, porosity, grain size, axial shortening, sampled depth, elastic wave velocity, geologic age, stratigraphic level and tectonic environment. The mode of deformation, angle of fracture, and strain at fracturing are related to the ratio of shearing stress to normal stress on the plane of fracture or to the ratio of the maximum strength to the confining pressure. The failure type corresponds alrnost to the deformational behavior, and the change among failure types seems to be continuous. The " visco-ductile " flow is observed in extreme porous rocks, possibly because the framework is crushed by higher pressure than formerly applied. The strength of sedimentary rocks increases with diminution of porosity. Because of compaction, the rocks become, generally, stronger and less ductile with the sampled depth and with geologic age. The degree and effect of compaction, however, are much influenced by the lithofacies and tectonic history, The degree of strengthening with geologic age is the greatest in argillaceous rocks, greater in arenaceous rocks and less in pyroclastic rocks. Among six areas studied, there exists an interesting contrast in deformational behavior and strength. The rocks in Joban and Miura districts are much more ductile and weaker than rocks in the other areas. The confining pressure of ductile -to- visco-ductile transition and degree of strengthening with geologic age, too, suggest that very lower compressive stress has been applied on the rocks in Joban and Miura districts than in the other areas.