岩石边坡潜在失稳区域微震识别方法

 为深入研究锦屏一级水电站左岸边坡深部岩体微震活动规律并评价边坡稳定性，在已有微震监测资料基础上，结合常规监测数据，并借助RFPA有限元数值模拟手段，分析左岸边坡深部岩体微破裂萌生、发育和扩展的演化机制，解释高程1 829 m处2#固结灌浆平洞多点位移计变化与微震事件时空分布规律之间的内在联系，再现典型剖面边坡渐进破坏全过程，重点阐述高程1 885 m坝顶平台裂缝形成机制。综合施工工况和工程地质情况分析，表明微震监测系统可以有效地识别和圈定边坡深部岩体微破裂区域和潜在滑裂面，边坡外观变形及微震活动性与该部位地质构造及灌浆活动有密切关系，灌浆导致的应力重分布和边坡内部天然裂隙带错动变形是诱发高程1 885 m坝顶平台裂缝的主要原因。研究结果为更好地理解和分析复杂应力条件下岩石边坡变形及其微震活动性诱发失稳机制提供重要的参考。

IDENTIFICATION METHOD OF POTENTIAL FAILURE REGIONS OF ROCK SLOPE USING MICROSEISMIC MONITORING TECHNIQUE

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.