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在分析钻爆法和TBM法开挖下围岩应力状态的基础上,基于锦屏二级水电站深埋隧洞微震监测数据,对比研究了钻爆法和TBM法开挖条件下深埋隧洞的微震特性及岩爆风险。结果表明:1钻爆法开挖引起的围岩应力集中距洞壁较远,形成的应力梯度较小;而TBM法开挖引起的围岩应力集中临近洞壁,形成的应力梯度较大。2钻爆法开挖时围岩应变能主要集中在爆破后数小时,尤其是在1 h内释放,而TBM法以连续的方式开挖卸载,剧烈的能量释放伴随着施工全过程。3TBM法开挖导致的事件震级及震源破裂尺度均比钻爆法开挖引起的大。4钻爆法开挖时,围岩积聚的应变能大多以岩体破裂的形式耗散,以岩爆形式显现的较少;而TBM法开挖时,围岩应变能常逐次释放,导致事件频繁发生,而且部分应变能以岩爆形式显现,一般地,同一小范围内常多次发生轻微岩爆,高等级岩爆孕育过程中常伴有低等级岩爆,如中等岩爆发生前伴有轻微岩爆,强烈岩爆孕育过程中伴有轻微和(或)中等岩爆,以此类推。综合上述研究结果认为,在具有强岩爆风险的深埋隧洞中,就防治岩爆而言,钻爆法优于TBM法。
Based on the analysis of the stress state of the surrounding rock under the excavation of the drilling and blasting method and the TBM method, based on the microseismic monitoring data of the deep tunnel of Jinping Hydropower Station, the microseismic Features and rock burst risk. The results show that: 1, the stress concentration of the surrounding rock caused by the excavation of the drilling and blasting method is farther away from the wall, and the stress gradient formed is smaller; while the surrounding rock stress caused by the TBM excavation is concentrated near the wall and the stress gradient is larger. 2 Drilling and blasting method of surrounding rock strain energy mainly concentrated in a few hours after blasting, especially in 1 h release, and TBM excavation unloading continuous manner, accompanied by intense energy release with the whole process. The magnitude of events and source rupture caused by 3TBM excavation are all larger than those caused by the excavation of the drill-blasting method. 4 Drilling and blasting excavation, the surrounding rock strain energy mostly in the form of rock mass dissipation in the form of rock burst is less; and TBM excavation, the surrounding rock strain can often release one after another, leading to events Frequent rockburst occurs frequently and part of the strain appears as rockburst. Generally, slight rockburst occurs frequently and frequently in the same small area. Low grade rockburst is often accompanied by high-grade rockburst inoculation, Rock bursts, intense rock bursts with mild and / or moderate rock burst, and so on. Based on the above results, it is concluded that in the deep tunnel with strong rock burst risk, the blasting method is superior to the TBM method in preventing and controlling rock burst.