| Project/Area Number |
63460189
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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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 Kumamoto Univ., Dept. Materials Science & Resource Engin., Professor, 工学部, 教授 (40040373)
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| Co-Investigator(Kenkyū-buntansha) |
KOIKE Katuaki Kumamoto Univ., Dept. Materials Science & Resource Engin., Research Associate, 工学部, 助手 (80205294)
OHMI Michito Kumamoto Univ., Dept. Materials Science & Resource Engin., Professor, 工学部, 教授 (30040405)
OBARA Yuzo Kumamoto Univ., Dept. Materials Science & Resource Engin., Associate Professor, 工学部, 助教授 (50135315)
KANEKO Katuhiko Kumamoto Univ., Dept. Materials Science & Resource Engin., Associate Professor, 工学部, 助教授 (20128268)
SUGAWARA Katuhiko Kumamoto Univ., Dept. Materials Science & Resource Engin., Professor, 工学部, 教授 (60109668)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥6,600,000 (Direct Cost: ¥6,600,000)
Fiscal Year 1989: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1988: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | In-situ Rock Stress / Geological Discontinuity / Hemispherical-ended Borehole Technique / Stress Relief Technique / Sleeve Fracturing / Elasto-plastic Analysis / Displacement Fields / Rock Properties / 球面孔低ひずみ法 / 水圧破砕法 / 応力解析 |
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| Research Abstract |
The initial stress measurement is indispensable to construct large rock cavern, because of the fact that mechanical behavior of rock mass around the rock cavern is dominated by the initial stress state remarkably. On the other hand, in order to estimate the stability of the rock cavern and control the construction of it, it is of important to evaluate the stress state around the rock cavern on construction or after the completion of the excavation, namely the induced stress. These stress states are considered to be affected by geological discontinuities, e.g.
joints and faults. Systematic stress measurement of the field, e.g. systematic measurement of the stress distribution around the rock cavern, are need to confirm the influence of the geological discontinuities.
Hemispherical-ended borehole technique is one of the methods that the stress tensor can be determined from the measurement in a single borehole. In this study, the initial stress measurement by the hemispherical-ended borehole technique are performed for the two areas. One is the measurement adjacent to active fault in gneiss and the other is the measurement in jointed quartz diorite. From these results, the relation between the movement of the fault and state of initial stress is clarified and the Possibility of predicting the unstable region for the excavation of tunnel is suggested.
Furthermore, a new method for elasto-plastic stress analysis of underground rock cavern, under the condition of biaxial initial stress, is presented by jointing two existing methods, a boundary element method for elasticity and a characteristics method for plasticity. Improvement of the accuracy of DDM analysis on the crack problem and the applicability of DDM to the stress analysis of the jointed rock are also discussed. As a result, it is confirmed that the stress and displacement fields can be analyzed sufficiently and accurately using those methods proposed by this study.
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