两河口水电站地下厂房开挖过程微震活动特征分析  

Characteristics of micro-seismic activity due to excavation for underground powerhouse at Lianghekou hydropower station

作　　者：郭亮[1] 戴峰[1] 徐奴文[1] 沙椿 廖伟 张鹏 何刚 

机构地区：[1]四川大学水力学与山区河流开发保护国家重点实验室,成都610065 [2]中国电建集团成都勘测设计研究院有限公司,成都610072 [3]雅砻江流域水电开发有限公司,成都610051

出　　处：《中国科技论文》2017年第19期2273-2280,共8页China Sciencepaper

基　　金：高等学校博士学科点专项科研基金资助项目(20130181110044);国家自然科学基金资助项目(51679158)

摘　　要：为识别和圈定开挖扰动过程地下厂房围岩损伤区域,分析评价围岩稳定性,构建了ESG微震监测系统,对围岩内部微破裂活动开展实时监测。监测结果表明:监测期间出现了2个微震事件聚集区域,均与母线洞爆破开挖扰动及母线洞与主变室边墙的交叉临空面形成有关。地下厂房微震活动存在明显的随施工扰动控制的时空迁移演化规律,分析其规律特征可为支护施工提供针对性参考。E_S/E_P为微震事件S波和P波能量比值,聚集区域Ⅰ约75%的微震事件E_S/E_P值小于10,表明微破裂以拉伸型破坏为主。同时,该区域围岩变形松弛前,微震事件具有"短期聚集、视应力迅速增加、视体积缓慢增长"的特点,可作为围岩变形预警的定性判别指标。研究成果可为两河口水电站地下厂房后期施工支护提供参考。The underground powerhouse of Lianghekou hydropower station was deeply buried under high ground stress and complicated geological conditions.To delineate rock mass damage zones and analyze the stability of underground powerhouse subjected to excavation disturbance,an ESG monitoring system was used to perform real-time monitoring against the inner microfracture activity of surrounding rock mass.Monitoring results indicated that:1)During the monitoring there were 2 micro-seismic(MS)events clustering areas,which were both related to blasting excavation disturbance of bus tunnel and the formed crossed free surfaces;2)The MS activity has the regularity of temporal and spatial evolution subjected to construction disturbance,which can be analyzed to provide a pointed reference for the support construction;3)Approximately 75% of MS events has E_S/E_Pvalue below 10 in MS events clusterⅠ,which indicated that the micro fractures were mainly dominated by tensile failure.Meanwhile,before the deformation of relaxed deformation in this area,the MS events increased and collected rapidly,the apparent stress increased quickly,but the apparent volume value grew slowly.The research results can provide reference for the later construction of underground powerhouse at Lianghekou hydropower station.

关 键 词：微震监测 两河口水电站 地下厂房 围岩稳定 

分 类 号：TV223[水利工程—水工结构工程] TV731.6