高地应力区深埋洞室开挖过程岩体力学响应与岩爆倾向性分析  

Analysis of Rock Mass Mechanical Response and Rockburst Tendency DuringExcavation of Deep Buried Chamber in High Ground Stress Area

作　　者：马天昌 MA Tianchang(The 5th Engineering Co.,Ltd.of China Railway Construction Bridge Engineering Bureau Group,Chengdu Sichuan 610500,China)

机构地区：[1]中铁建大桥工程局集团第五工程有限公司,四川成都610500

出　　处：《铁道建筑技术》2024年第1期148-153,共6页Railway Construction Technology

基　　金：中国铁建大桥工程局集团有限公司科技创新项目(DQJ-2020-B27)。

摘　　要：为探究高地应力区深埋洞室开挖卸荷过程诱发的岩爆问题,以双江口水电站洞室溢洪道为工程背景,基于微震监测技术分析了洞室开挖过程中岩爆微震事件时空分布特征,确定了洞室岩爆灾害的风险部位。通过有限元软件构建了洞室的初始应力场,将有限元得出的洞室损伤区云图与现场微震监测结果进行对比分析。在此基础上,分析了洞室溢洪道变形和应力变化规律,揭示了洞室变形机制,探讨了洞室岩爆等级。研究结果表明:洞室开挖初期,左侧拱肩位置先发生变形;随着洞室大规模开挖卸荷,左侧边墙应力突然释放易出现脆性破坏;洞室开挖后期,左侧边墙与底板交汇位置因出现应力集中导致围岩劈裂的破坏现象。同时,根据Barton判据、Rb/σ1判据和陶振宇判据对洞室拱脚、拱肩和拱顶位置进行岩爆分析,拱脚位置在开挖过程中易发生严重岩爆现象,拱肩和拱顶位置可能出现轻微岩爆或中等岩爆现象。In order to explore the rock burst problem induced by the unloading process of deep buried tunnel excavation in high stress areas,taking the cavernous spillway of Shuangjiangkou Hydropower Station as the engineering background,the spatiotemporal distribution characteristics of rock burst microseismic events during the tunnel excavation process were analyzed based on microseismic monitoring technology,and the risk location of rock burst disasters in the tunnel was determined.The initial stress field of the tunnel was constructed using finite element software,and the cloud map of the tunnel damage area obtained from the finite element method was compared and analyzed with the on-site microseismic monitoring results.On this basis,the deformation and stress changes of the spillway in the tunnel were analyzed,the deformation mechanism of the tunnel was revealed,and the level of rock burst in the tunnel was discussed.The research results indicate that in the early stage of tunnel excavation,the left arch shoulder position undergoes deformation first;with the large-scale excavation and unloading of the tunnel,the sudden release of stress on the left side wall is prone to brittle failure;In the later stage of tunnel excavation,the intersection of the left side wall and the bottom plate resulted in stress concentration leading to the failure of the surrounding rock to split.Meanwhile,according to Barton′s criterion and Rb/σ1 criterion and Tao Zhenyu′s criterion,rock burst analysis is conducted on the positions of the arch foot,arch shoulder,and arch crown of the tunnel.The arch foot position is prone to serious rock burst phenomena during the excavation process,and the arch shoulder and arch crown positions may experience slight or moderate rock bursts.

关 键 词：洞式溢洪道 高地应力 岩爆倾向性 

分 类 号：TV554.16[水利工程—水利水电工程]