| Project/Area Number |
06555311
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| Research Category |
Grant-in-Aid for Developmental 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 | THE UNIVERSITY OF TOKYO |
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Principal Investigator |
YAMATOMI Jiro University of Tokyo, School of Engineering Professor, 大学院・工学系研究科, 教授 (70107548)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEUCHI Tatsuya United System Engineers Co. Ltd. Head of Research Department, 研究本部, 研究本部長
MOZUMI Hiroshi Kamioka Mining & Smelting Co.Ltd. Research Manager, 地下利用事業室, 研究開発担当主査
ADACHI Tsuyoshi University of Tokyo, School of Engineering Research Associate, 大学院・工学系研究科, 助手 (40262050)
MOGI Gento University of Tokyo, School of Engineering Associated Professor, 大学院・工学系研究科, 助教授 (70182160)
SASAKI Kyuro Akita University, Mining College Associated Professor, 鉱山学部, 助教授 (60178639)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥8,700,000 (Direct Cost: ¥8,700,000)
Fiscal Year 1995: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1994: ¥5,700,000 (Direct Cost: ¥5,700,000)
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| Keywords | Rock Monitoring / Long-term Stability of Rock / AE(Acoustic Emission) / Propagation Velocity / Attenuation Constant / Source Location / 岩石力学 / モニタリングシステム / 微小地震 / 弾性波伝播速度 / 減衰特性 / 波形解析 / パワースペクトラム |
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| Research Abstract |
Development of a long-term rock monitoring system and its application test is the purpose of the present research project. The employed method for rock monitoring is to detect AE signals emitted around micro-scaled fracturing, which can be used to predict a large-scaled instability inrock mass.
First, we have made a couple of AE sensors incorporating operational amplifiers and highpass filters ; they were designed to be installed in drilled holes in rock mass and their performances were also examined in the laboratory.
Three kinds of rocks were uniaxially compressed and elongated to induce microscopic fractures in order to check whether our handmade AE sensors can detect any AE signals and identify any characteristics of AE wavetrains and spectra. It was found, there were two types of AE signals. One of them has a predominant frequency around 100 kHz and the other one has low frequency components around 50 kHz. We could not find clear correlation between AE characteristics and failure modes/rock types, however. From the tensile experiments on same kinds of rocks, one of distinctive features of AE signals is found to be high frequency components superimposed on low frequency ones. However, it was impossible to identify whether these signals are inherent in extension tests. Moreover, source location tests were also conducted in the laboratory to examine the applicability of the monitoring system in in-situ.
Finally, we have had in-situ measurements of propagation velocity of AE and attenuation constant in the Tochibora Mine of Kamioka Mining & Smelting Co.Ltd., in Gifu prefecture. Wecould obtain successful results about field measurements and confirm the reliability of the developed AE monitoring systems ; however, it was unfortunate that none of naturally induced AE were picked-up during the site examination. We hope that the present research may contribute to further investigation and development of long-term rock monitoring.
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