| Project/Area Number |
62550467
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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 | Faculty of Science and Engineering, Waseda Univ. |
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Principal Investigator |
HASHIMOTO Bunsaku (1988) Faculty of Science and Engineering, Waseda Univ., 理工学部, 教授 (50063269)
萩原 義一 (1987) 早稲田大学, 理工学部, 教授 (50063095)
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| Co-Investigator(Kenkyū-buntansha) |
HAGIWARA Yoshikazu Faculty of Science and Engineering, Waseda Univ., 理工学部, 名誉教授 (50063095)
NOGUCHI Koji Faculty of Science and Engineering, Waseda Univ., 理工学部, 助教授 (50147948)
橋本 文作 早稲田大学, 理工学部, 教授 (50063269)
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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 |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1988: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Elastic Wave / Seismic Attenuation Spectrum / Discontinuity / 岩盤分類 / クラスター分析 / 弾性波減衰特性 / パワー / スペクトル減衰比 / 重回帰分析 |
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| Research Abstract |
Discontinuities in rock has serious effects on the deformation and destruction of rock, we have investigated the relation between aperture of discontinuities in rock and power spectrum attenuation of elastic wave. And attenuation spectrum of seismic wave were examined using the cluster analysis method in order to correlate with the classification of rock. The results obatined are summarized as follows; 1. Power spectrum attenuation shows a wide change according to the difference of rock properties. 2. Amajor cause of the change depends on aperture of discontinuities which are not filled with materials. 3. At certain frequencies, power are attenuated dependent on the ratio of the wavelength to the aperture of discontinuity. It is proved that power spectrum attenuation ratio is controlled primarily by the aperture of discontinuities in rock. 4. Properties of discontinuity, which are important parameters in the conventional methods of rock mass classification, have a considerable influence on seismic attenuation. We can, therefor, use the character of seismic attenuation as assesments of the fracfured state of rock masses. 5. The results of cluster analysis of attenuation spectrum agree with each other in spite of the definitions of dissimilarity between clusters. 6. Good correspondence is recognized between the result of the conventional rock classification method and the result of classification by cluster analysis of seismic attenuation spectrum. As described above, power spectrum attenuation ratio is an effective physical quantity for detecting the change of aperture, estimating the aperture of discontinuity, and the classification by cluster analysis of seismic attenuation spectrum is a feasible method of characterizing of rock masses.
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