Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7206733 | International Journal of Rock Mechanics and Mining Sciences | 2014 | 7 Pages |
Abstract
We monitored acoustic emission (AE) events associated with the progressive excavation of an underground chamber for a powerhouse at a depth of 280Â m below the surface in a porphyritic rock mass of the Mesozoic era. Large AE events rarely occur under such conditions; specifically, low-stress environments due to the shallow depth, careful excavation, and sufficient reinforcement. However, upon employing sensitive, high-frequency monitoring (15 to 40Â kHz) in a relatively small region, some AE events were located and, by using fault-plane solutions, their fracture mechanisms were identified. Strike and dip angles of fracture planes and the directions of principal stresses, all derived from fault-plane solutions, were consistent with the directions of dominant joint surfaces, the measured initial stress conditions, and the shape of nearby excavated openings. This suggests that by employing sensitive, high-frequency AE monitoring, fault-plane solutions can be effectively utilized as a tool to assess the stability of a chamber excavated at shallow depth, as well as in deep mines where fault-plane solutions have already been used in practice to assess and control rockbursts.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geotechnical Engineering and Engineering Geology
Authors
Tsuyoshi Ishida, Tadashi Kanagawa, Yasuo Uchita,