1993 Fiscal Year Final Research Report Summary

Study on stress redistribution around a rock chamber based on field measurements with progressive excavations

Research Project

Project/Area Number	04805064
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	資源開発工学
Research Institution	Yamaguchi University
Principal Investigator	SHIMIZU Norikazu Yamaguchi Univ., Fac.of Engineering, Assistant Professor, 工学部, 助教授 (70150357)
Co-Investigator(Kenkyū-buntansha)	SANO Osamu Yamaguchi Univ., Fac.of Engineering, Assistant Professor, 工学部, 助教授 (20127765)
Project Period (FY)	1992 – 1993
Keywords	Underground Chomber / Stress Redistribution / Acoustic Emssion / Field Measurements
Research Abstract	Although stress redistribution due to excavation is most important phenomenon to assess stability of an underground chamber, it does not seem to be made clear sufficiently by field measurements. We took note of the two methods of field measurements for that ; one is Acoustic Emission monitoring, and the other one is the measurement of small strain changes in rock. We developed the two methods through small scale in situ tests and applied them to monitor three real chambers for underground powerhouses. As the results, we found these methods are applicable to investigate stress redistribution in fields. Furthermore, we observed that stress does not always concentrate in only one location near a chamber wall, and, in some cases, it concentrates in two or three locations around chamber depending on interlocking of rock masses separated by discontinuous planes.