摘要
Rock mass large deformation in underground powerhouse caverns has been a severe hazard in hydropower engineering in Southwest China.During the development of rock mass large deformation,a sequence of fractures was generated that can be monitored using microseismic(MS)monitoring techniques.Two MS monitoring systems were established in two typical underground powerhouse caverns featuring distinct geostress levels.The MS b-values associated with rock mass large deformation and their temporal variation are analysed.The results showed that the MS bvalue in course of rock mass deformation was less than 1.0 in the underground powerhouse caverns at a high stress level while larger than 1.5 at a low stress level.Prior to the rock mass deformation,the MS b-values derived from both the high-stress and low-stress underground powerhouse caverns show an incremental decrease over 10%within 10 d.The results contribute to understanding the fracturing characteristics of MS sources associated with rock mass large deformation and provide a reference for early warning of rock mass large deformation in underground powerhouse caverns.
地下厂房洞室群围岩大变形已成为中国西南地区水电工程的严重灾害,围岩大变形孕育过程中将产生一系列的岩石破裂,运用微震监测技术可监测到这些破裂信息。在地应力水平不同的两个典型地下厂房洞室群构建精度微震监测系统,分析了围岩大变形微震b值及其时间变化特征。结果表明,高地应力地下厂房洞室群围岩大变形过程微震b值小于1.0,而低地应力情况下微震b值大于1.5。对于高、低地应力地下厂房洞室群而言,围岩大变形前十日内,微震b值均出现超过10%的下降。研究成果有助于提高围岩大变形微震震源破裂特征的认识,也可为地下厂房洞室群围岩大变形预警提供重要参考。
作者
LI Biao
DING Quan-fu
XU Nu-wen
DAI Feng
XU Yuan
QU Hong-lue
李彪;丁泉富;徐奴文;戴峰;许媛;曲宏略(School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China;State Key Laboratory of Hydraulics and Mountain River Engineering,College ofWater Resource and Hydropower,Sichuan University,Chengdu 610065,China;Department of Engineering Science,University of Oxford,OX51PF,United Kingdom)
基金
Projects(51809221,51679158)supported by the National Natural Science Foundation of China
Project(KFJJ20-06M)supported by the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology),China。
