1987 Fiscal Year Final Research Report Summary
Application of Acoustic Emission Technique to Prediction of Rockburst
| Project/Area Number |
60460185
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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 | Muroran Institute of Technology |
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Principal Investigator |
SATO Kazuhiko Professor, Muroran Institute of Technology, 工学部, 教授 (30002009)
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| Co-Investigator(Kenkyū-buntansha) |
ITAKURA Ken-ichi Research Associate, Muroran Institute of Technology, 工学部, 助手 (20168298)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Prediction of rockburst / Acoustic emission / Moment tensor inversion / 構造不安性 |
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| Research Abstract |
The temporal and spatial changes of acoustic emission prior to the main faulting of rock have been investigated to clarify precursor phenomena of rockburst. Under uniaxial compression with constant strain rate, AE tends to migrate just before the ultimate fracture, although AE concentrates along the eventual fault plane with increase of stress. At this phase AE count rate and event rate are also temporarily reduced. The temporal and spatial anomalies of AE proceding macroscopic fracture can be referred to stress relaxation associated with integration of microcracks around the eventual fracture plane and growth of macrocrack. The precursive phenomenon of AE confirmed in this study is promising to prediction of rockburst.
In addition, the source mechanism of AE has been determined by means of moment tensor inversion. The scale model study has shown that AEs in front of a flat excavation such as mining panel in seam deposit are generated by uniaxial compression or double couple. On the other hand, AEs behind the face of excavation are caused by various modes of force system including uniaxial tension. The strain analysis in the scale model study suggests that the source mechanism of AE corresponds well to the stress state around the excavation.
The criteria for occurrence of microseismic event has been also derived considering the global instability of a system comprising of the yielded region and its surroundings. The criteria are formulated in terms of inequalities for various stress states such as polyaxial, biaxial, and uniaxial stresses. The criteria imply taha occurrence of microseismic event is controlled by a few paramters representing the properties of deformation both in pre- and post failure regions.
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Research Products
(10 results)
