IDENTIFICATION METHOD OF POTENTIAL FAILURE REGIONS OF ROCK SLOPE USING MICROSEISMIC MONITORING TECHNIQUE
(1. State Key Laboratory of Coastal and Offshore Engineering，Dalian University of Technology，Dalian，Liaoning 116024，China；2. Center for Rock Instability and Seismicity Research，Dalian University of Technology，Dalian，Liaoning 116024，China；
3. HydroChina Chengdu Engineering Corporation，Chengdu，Sichuan 610072，China)
Abstract：Based on the results of microseismic monitoring data recorded，the law of microseismicity occurring in the deep rock masses at left bank slope of Jinping I hydropower station is investigated；and the slope stability is evaluated combining with conventional measurement data and numerical simulation using realistic failure process analysis(RFPA) approach. The following aspects are taken into consideration：(1) The evolution mechanism of micro-fractures initiation，growth and expansion in deep rock masses of rock slope is performed. (2) The internal relation between tempo-spatial distribution regularity of microseismic events and variances of multiple position extensometers in consolidation grouting tunnel #2 at the elevation of 1 829 m are interpreted. (3) The full progressive failure processes of rock slope with typical section have been reproduced. (4) The generation mechanism of cracks in the platform of dam crest at the elevation of 1 885 m is in-depth analyzed. Incorporating with site operation conditions and engineering geology，this leads to conclusions：Firstly，microseismic monitoring network installed at right bank slope could availably identify and delineate failure regions and potential sliding surface in deep rock masses. Secondly，visual deformation of rock slope and microseismicity are closely related to geological structures and grouting in the weak-layers. Finally，stress redistribution induced by high pressure cement grouting and slippage deformation of pre-existing fissure zones are the primary factors causing cracks in the platform of dam crest at the elevation of 1 885 m. The research results provide important references to the understanding and analysis of rock slope deformation and associated microseismicity-induced instability mechanism under complex stress conditions.
2011, Vol. 30 
