不同中间主应力下花岗岩失稳过程的微震信号演化特征  

Evolution Characteristics of Microseismic Signals During Granite Failure Under Different Intermediate Principal Stresses

作　　者：苏国韶[1,2,3] 胡诗红 蒋剑青 任泓宇 SU Guo-shao;HU Shi-hong;JIANG Jian-qing;REN Hong-yu(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Provincial Engineering Research Center of Water Security and Intelligent Control for Karst Region,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学土木建筑工程学院,广西南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004 [3]广西大学广西岩溶区水安全与智慧调控工程研究中心,广西南宁530004

出　　处：《水电能源科学》2023年第1期142-146,共5页Water Resources and Power

基　　金：国家自然科学基金项目(52169021,51869003);广西高等学校高水平创新团队及卓越学者计划(202006)。

摘　　要：为探究深埋隧洞围岩失稳破坏的微震演化特征,开展了不同中间主应力(σ2)下的花岗岩双轴压缩试验,运用微震监测系统和高清摄像机实时监测花岗岩破裂失稳过程。分析了不同σ2下岩石失稳过程的微震b值和主频的演化特征,并提出微震能量释放指标来描述岩石破坏的剧烈程度。结果表明,随着σ2的增加,累积微震能量释放、岩石失稳前夕lgN/b的最大值和低频信号占比、岩石失稳时刻的微震能量释放率均增加,而在岩石失稳前夕b值最小值减少。此外,岩石失稳的微震前兆有b值下降至低于0.8、lgN/b上升至大于3和高幅低频信号出现。岩石出现板裂的前兆是高幅低频信号伴随少量高幅高频信号同时出现;岩石出现岩爆破坏的前兆是b值下降至小于0.5,lgN/b上升至大于5,且高幅值的信号只出现在低频带。To explore the microseismic evolution characteristics of instability failure of surrounding rock of deep buried tunnel, biaxial compression tests of granite were carried out under different intermediate principal stresses(σ2). The microseismic monitoring system and high-definition camera were used to monitor and record the failure of granite in real time. The evolution characteristics of microseismic b value and dominant frequency of rock failure process under different σ2conditions were analyzed, and the index of microseismic energy release(MSER) was proposed to describe the degree of rock failure. The results show that with the increase of σ2, the cumulative microseismic energy release, the maximum value of lgN/b and the ratio of low frequency signal before rock failure, and the microseismic energy release rate at rock failure time all increase, while the minimum value of b value before rock failure decreases. In addition, the microseismic precursor of rock instability lists as follows: b value drops to less than 0.8;lgN/b rises to more than 3;High amplitude and low frequency signal appears. The precursors of rock slabbing are high amplitude low frequency signals accompanied by a small number of high amplitude high frequency signals, while the precursors of rockburst failure are that b value drops to less than 0.5, and lgN/b rises to more than 5, and high amplitude signal only appears in the low frequency band.

关 键 词：深埋隧洞 微震 试验研究 中间主应力 

分 类 号：TV223.1[水利工程—水工结构工程] TU45[建筑科学—岩土工程]