深埋引水隧洞塌方孕育过程微震规律研究:以Neelum-Jhelum工程为例  

Research on microseismic evolution law of collapse in deep-buried headrace tunnel:A case study from the Neelum-Jhelum hydropower project

作　　者：谭双[1,2,5] 李邵军 王雪亮[3] 陈炳瑞 肖亚勋[1] 丰光亮[1] 李鹏翔[4] TAN Shuang;LI Shaojun;WANG Xueliang;CHEN Bingrui;XIAO Yaxun;FENG Guangliang;LI Pengxiang(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Railway Engineering Consulting Group Co.,Ltd.,Beijing 100055,China;Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines,Northeastern University,Shenyang,Liaoning 110819,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]中铁工程设计咨询集团有限公司,北京丰台100055 [4]东北大学深部金属矿山安全开采教育部重点实验室,辽宁沈阳110819 [5]重庆大学

出　　处：《岩石力学与工程学报》2018年第A02期4115-4124,共10页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科岩基金重点项目(U1765206,11232014)~~

摘　　要：深埋隧洞复杂地质条件和开挖卸荷导致塌方事故频发,严重威胁现场施工人员生命财产安全。为降低巴基斯坦Neelum-Jhelum工程塌方灾害对施工的影响,构建微震监测系统,研究塌方孕育过程微震活动的时空演化规律。研究结果表明:(1)掌子面逐渐靠近但未揭露塌方区岩体时,微震事件较少,累积释放能快速上升,累积视体积缓慢增长,能量指数突增后基本稳定;塌方区岩体开挖揭露后,微震事件较多,累积释放能缓慢增长,累积视体积突增,能量指数突减;(2)塌方区局部微震事件丛集,丛集位置与钙质岩性交界面发育有关,多数微震事件发生于离洞壁3倍隧洞半径范围内;(3)塌方区围岩破裂机制演化规律有“先剪切,后张拉”的特征;(4)塌方的孕育有明显的阶段特征:钙质充填岩性交界面剪切滑动→围岩揭露后产生平行张拉裂纹→悬臂梁岩块受压拉裂→裂纹贯通,岩块受重力塌落。研究结果为深部塌方灾害的预警和防治提供参考。Complex geological condition and excavation in deep tunnel frequently led to collapse accidents,which seriously threatened the safety of life and property of workers on site. In order to reduce the impact of collapse on the Neelum-Jhelum project in Pakistan,a microseismic monitoring system was constructed to study the temporal and spatial evolution law of the microseismic activity during the development of collapse. The research showed that,when the working face was gradually approaching but didn′t reveal rock mass in the collapse zone,fewer microseismic events occurred,and the cumulative released energy increased rapidly. The cumulative apparent volume grew slowly and the energy index was basically stable after sudden increase. As rock mass in the collapse zone being revealed by excavation,more microseismic events occurred. The cumulative released energy increased slowly,the cumulative apparent volume sharply increased,and the energy index suddenly decreased. Microseismic events clustered in a certain part of collapse zone,where an interface filled with calcite developed. Most of the microseismic events occurred within the 3 times of the tunnel radius from the cavern wall in surrounding rock. The mechanism of rock cracks in the collapse zone was "shearing at the first and tensioning in the end". The development of collapse showed obvious stage characteristics:the interface filled with calcite slide→parallel tensile cracks occurred in surrounding rock after revealed→The cantilever rock beam cracked on the end→The cracks penetrated and the rock blocks fell by gravity.

关 键 词：岩石力学 深埋隧洞 塌方 微震监测 孕育过程 Neelum-Jhelum工程 

分 类 号：TU45[建筑科学—岩土工程]