1986 Fiscal Year Final Research Report Summary
Influence of rate of change in stress field to the fracture phenomena
| Project/Area Number |
60550445
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
資源開発工学
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| Research Institution | Yamaguchi University |
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Principal Investigator |
OGINO Shoji Yamaguchi University, Professor, 工学部, 教授 (90035014)
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| Co-Investigator(Kenkyū-buntansha) |
SANO Osam Yamaguchi University, Research assistant, 工学部・資源工学科, 助手 (20127765)
MIZUTA Yoshiaki Yamaguchi University, Assistant Professor, 工学部・資源工学科, 助教授 (20107733)
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| Project Period (FY) |
1985 – 1986
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| Keywords | triaxial test / confining pressure / strain rate |
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| Research Abstract |
In the mechanical testing of metals, the applied stress is usually uniaxial. However, for rocks, three principal stresses are commonly non zero, because the triaxial stress state can effectively simulate overburden stress. The usual triaxial tests are carried out by stressing the rock under confining pressure. However, in most practical situations, the fracture of the rock occurs due to a creation of the free surfaces such as an under-ground openings. Then the maximum stress (tensile stress is taken to be positive) should be decreased. In this research, we introduce an new experimental procedure, depressing test. The new test start from the hydrostatic stress state, where the axial strain rate is kept constant. The confining pressure is decreased at various depressing rate simultaneously. Rock specimens fractured violently, while in usual confined test rock specimen behave ductile under relatively high confining pressure.
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