基于微震监测的顺层岩质边坡开挖稳定性分析  

Stability analysis of bedding rock slopes during excavation based on microseismic monitoring

作　　者：徐奴文[1,2] 李彪[2] 戴峰[2] 樊义林[3] 徐剑[3] XU Nuwen LI Biao DAI Feng FAN Yilin XU Jian(School of Civil Engineering, Shandong University, Jinan, Shandong 250100, China State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu, Sichuan 610065, China China Three Gorges Corporation, Beijing 100038, China)

机构地区：[1]山东大学土建与水利学院,山东济南250100 [2]四川大学水力学与山区河流开发保护国家重点实验室,四川成都610065 [3]中国长江三峡集团公司,北京100038

出　　处：《岩石力学与工程学报》2016年第10期2089-2097,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点基础研究发展计划(973)项目(2015CB057903);国家自然科学基金面上项目(51374149);教育部新世纪优秀人才(NCET–13–0382)~~

摘　　要：为评估白鹤滩水电站左岸顺层边坡开挖过程中的稳定性,构建高精度微震监测系统,通过实时监测和分析微震活动特征,圈定左岸边坡主要的损伤区域;借助RFPA有限元数值模拟方法,揭示左岸边坡岩石微破裂萌生、聚集、扩展直至贯通的演化机制,再现典型剖面边坡破坏全过程。研究结果表明：微震活动与开挖扰动密切相关,边坡开挖诱发的微震事件主要分布在大坝拱肩槽附近,沿层内错动带LS_（331）,LS_（337）及断层F_（17）上盘（610～700 m高程）条带状聚集,形成边坡主要的损伤区;边坡开挖卸荷作用下,LS_（331）,LS_（337）及F_（17）等软弱结构面剪应力集中突显,大量破裂单元也沿LS_（331）,LS_（337）及F_（17）持续聚集,导致边坡沿软弱结构面的失稳破坏,计算结果与微震活动空间宏观演化趋势基本一致。研究结果可为边坡后期开挖和支护提供参考,也可供同类顺层岩质边坡稳定研究借鉴。A high-precision microseismic（MS） monitoring system was installed to evaluate the stability of the left bank bedding slope at Baihetan during excavation. The main damage regions of the left bank slope were delineated through real-time monitoring and analyzing of the MS activities. The initiation,propagation,extension and coalescence mechanisms of mircocracks were revealed using the realistic failure process analysis（RFPA） approach. The full progressive failure processes of the rock slope at atypical section were reproduced. The MS activities were found to match well with the excavation disturbances. The MS events induced by the slope excavation were mainly distributed around the dam spandrel,especially along the internal staggered zones LS_（331）,LS_（337） and the hanging wall of fault F_（17）（610–700 m）,forming the main damage regions of the slope. Influenced by the excavation-induced unloading of the slope,the stress concentration was highlighted in the weak structures such as LS_（331）,LS_（337） and F_（17）,and myriads of rock failure elements continuously propagated in these regions,resulting in the rock failure along the weak structures. Numerical simulation results coincided with the trend of spatial macro evolution of MS activities.

关 键 词：边坡工程 顺层岩质边坡 微震监测 开挖 稳定性 数值模拟 

分 类 号：P642[天文地球—工程地质学]