| Project/Area Number |
62850116
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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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 | Kumamoto University |
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Principal Investigator |
OKAMURA Hiroshi Professor, Kumamoto University, 工学部, 教授 (40040373)
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| Co-Investigator(Kenkyū-buntansha) |
KOIKE Katsuaki Research associate, Kumamoto University, 工学部, 助手 (80205294)
OBARA Yuzo Associate professor, Kumamoto University, 工学部, 助教授 (50135315)
SUGAWARA Katsuhiko Professor, Kumamoto University, 工学部, 教授 (60109668)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1988: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1987: ¥4,900,000 (Direct Cost: ¥4,900,000)
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| Keywords | Hemispherical borehole technique / In-situ rock stress / 高精度 / 球状孔底ひずみ法 |
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| Research Abstract |
In the construction of rock cavern, it is important for the design and stability estimations of the rock cavern to measure the state of intial stresses as well as distribution of induced stresses in the rock mass around the cavern with high accuracy. In this project, the Hemispherical Ended Borehole Technique is developed for measurement of in-situ rock stresses and the miniaturization of the system and the improvement of the accuracy are performed. This system are applied to measure rock stress in the rock mass around the cavern. The results obtained in this project are as follows:
1) A new technique to measure the complete state of in-situ rock stresses in a single borehole are developed, which is called Hemispherical Ended Borehole Technique. The stress tensor is computed from 16 strains on the hemispherical bottom surface of a borehole. An arrangement of strain gauges to determin the stress tensor with high accuracy is discussed and a spherical strain cell to bond the strain gauges directly to the bottom surface at the designated stations is developed.
2) It is confirmed that the rock stresses with higher accuracy can be determined by using of the proposed method in comparison with the conventional method from the theoretical analyses and experiments using rock spacimens.
3) The in-situ rock stresses in the rock mass around the cavern are measured by the proposed method and the distribution of the stresses is determined. The extent of the failure zone around the cavern and the practical strength of the rock mass forming the ground arch can be estimated from the distribution of stresses.
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