荒沟抽水蓄能电站地下厂房开挖过程微震及电磁辐射活动特征研究  

Study on the characteristics of microseismicity and electromagnetic radiation activity of the underground powerhouse at Huanggou pumped storage power station subjected to the excavation

作　　者：周春华[1,2] 李云安[1] 尹健民[2] 汪洋[2] 周朝[2] ZHOU Chunhua;LI Yun'an;YIN Jianmin;WANG Yang;ZHOU Chao(Faculty of Engineering,China University of Geosciences,Wuhan,Hubei 430074,China;Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources,Yangtze River Scientific Research Institute,Wuhan,Hubei 430010,China)

机构地区：[1]中国地质大学工程学院,湖北武汉430074 [2]长江科学院水利部岩土力学与工程重点实验室,湖北武汉430010

出　　处：《岩石力学与工程学报》2019年第S02期3583-3594,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家重点研发计划项目(2016YFC0401803);国家自然科学基金委与广东省联合基金重点基金项目(U1711266);中央级公益性科研院所基本科研业务费项目(CKSF2019190/YT)。

摘　　要：为了研究黑龙江荒沟抽水蓄能电站地下厂房在深层开挖过程中诱发岩爆的前兆特征,综合采用微震与电磁辐射法对围岩微破裂进行了识别。通过分析监测范围内微震及电磁辐射活动的时空分布规律、诱发微破裂的前兆信息及监测结果的相关性,结果表明:(1)微震事件在空间上具有分区丛聚特征,个别聚集部位与早期岩爆位置高度吻合;不同时段内微震事件频次与外界施工扰动强度呈正相关;能量指数迅速下降及累积视体积大幅度增加,预示岩爆或大型围岩破裂事件的发生。(2)在地下厂房断层裂隙带内,电磁辐射强度的突变预示着岩爆或大型围岩破裂事件即将发生,电磁辐射脉冲数的峰值分布与局部应力场调整方向一致,且调整时间约为8 d。(3)两种监测方法分别揭示的围岩破裂空间分布基本一致,电磁辐射法所预示的前兆时间略早,而且监测结果反映的震源区局部应力场调整趋势相关性良好,即脉冲数峰值分布与震源区视应力迁移完全一致。工程实践证明,应用联合监测方法能有效识别地下工程围岩破裂等前兆信息,监测结果为深入开展岩爆监测预警提供了基础,对工程安全施工具有重要意义。In order to study the precursor characteristics of rock burst induced by deep excavation of the underground powerhouse at Huanggou pumped storage power station in Heilongjiang province,microseismic(MS)and electromagnetic radiation(EMR)monitoring methods are comprehensively applied to identify the micro-fracturing of the surrounding rock.By analyzing the temporal and spatial distribution law of the microseismicity and electromagnetic radiation activity in the monitoring range,the precursory information of the induced fractures and the correlation between the both monitoring results,the results show that:(1)The microseismic events are characterized by the regional clustering in space and some clustering positions are highly consistent with the zones where rock burst happened during the initial excavation,revealing the local stress in a continual readjustment process.There is a positive correlation between the frequency of microseismic events and the intensity of external disturbance in corresponding time intervals.The sharp decline of the energy index(EI)and the explosive growth of the cumulative apparent volume(CAV)generally indicates the occurrence of rock burst or large-scale rock rupture events.(2)In the fault fissure zone of the underground powerhouse,the significant change of electromagnetic radiation intensity indicates that rock burst or large-scale rupture will soon happen.The distribution of the peak electromagnetic radiation pulse number is consistent with the migration direction of the local stress field,as well the adjustment time of the local stress field is about 8 days.(3)The spatial distribution of surrounding rock fracture revealed by the two monitoring methods is consistent,and the precursor time resulted from electromagnetic radiation method is slightly earlier.There is a good correlation between the both results of the local stress field in the event source region,and the distribution of the peak electromagnetic radiation pulse number is in full accord with the migration of the apparent stress.

关 键 词：水利工程 岩爆 微震监测 电磁辐射 前兆信息 相关性 

分 类 号：TV31[水利工程—水工结构工程]