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Abstract Many deep cracks and faults，such as f2，f5 and lamprophyres，which may result in huge potential instable blocks，are the most significant factors that influence the stability of the left bank slope of Jinping I Hydropower Station. In order to real-time monitor and analyze microseismicity in deep rock mass of the left slope，an ESG microseismic monitoring system manufactured in Canada was installed in June，2009. It is the first time to introduce microseismic monitoring technique into high steep rock slope engineering in China. On the basis of setting up three-dimensional geological model of the left slope and optimizing the sensor emplacement，the positioning accuracy of the system has been adjusted according to artificial fixed blasting tests. The results show that seismic source location error is less than 12 m in the scope of the sensor array，which demonstrates microseismic monitoring system has a high positioning accuracy. The waveforms analysis and clustering are investigated and different types of waveforms have been distinguished. Moreover，the tempo-spatial distribution regularities of microseismic events are also analyzed. In addition，a preliminary delineation of deep rock mass deformation zone induced by microseismicity in left bank slope is provided. Furthermore，the stress field and potential slip surface of left slope are simulated by RFPA，which is corresponding to the results of site exploration and microseismic monitoring. This research indicates that the design and implementation of microseismic monitoring system can meet the global monitoring of deep rock mass deformation，which could identify the potential rock damage regions and sliding surface. It will provide a reference for grouting and reinforcement of the left bank slope. A new idea on stability analysis of high rock slopes can thus be obtained.
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Received: 23 November 2009
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