(1. State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University,Chengdu,Sichuan 610065,China;2. School of Civil and Hydraulic Engineering,Shandong University,Jinan,Shandong 250061,China;3. HydroChina Chengdu Engineering Corporation,Chengdu,Sichuan 610072,China;4. School of Civil Engineering,Dalian University of Technology,Dalian,Liaoning 116024,China)
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.
徐奴文1,2,戴 峰1,周 钟3,沙 椿3,唐春安4. 岩质边坡微震事件b值特征研究[J]. 岩石力学与工程学报, 2014, 33(sl): 3368-3374.
XU Nuwen1,2,DAI Feng1,ZHOU Zhong3,SHA Chun3,TANG Chun?an4. STUDY OF CHARACTERISTICS OF b VALUE FOR MICROSEISMIC EVENTS IN HIGH ROCK SLOPE. , 2014, 33(sl): 3368-3374.
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