Title of Paper:Study of characteristics of b value for microseismic events in high rock slope

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Date of Publication:2014-01-01

Journal:Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

Included Journals:EI、PKU、ISTIC、Scopus

Volume:33

Issue:SUPPL.1

Page Number:3368-3374

ISSN No.:10006915

Abstract:The magnitude-frequency relation(b value) of microseismic events recorded at the left bank slope of Jinping first stage hydropower station was analyzed. In order to in-depth investigate the slope stability and resolve the complex surface conditions of highly fractured rock mass, a microseismic monitoring system was implemented at the rock slope in June 2009 based on common monitoring instrument including multipoint extensometer and graphite rod convergence gauge. Seismic source parameters such as magnitude, location and time were captured during the monitoring period. The variation of b value was thus determined with time and excavation-induced microcrackings were identified and delineated after analyzing the monitoring data recorded from June 2009 and to 2011. Results show that rock mass damage is closely related with b value. The b value of microseismic events at the dam spandrel equals 0.87, showing the microseismicity plays little effect on the rock slope stability. Meanwhile, the little increase of b value(from 0.49 to 0.65) at the unknown geological structure indicated the hazard probability of rock mass failure inside the unknown geological structure of left slope decreased. Results can provide references for predicting rock mass instability and improving monitoring accuracy in similar rock slopes.