深埋隧洞TBM掘进微震实时监测与特征分析

冯夏庭　陈炳瑞

摘要：针对深埋硬岩隧洞TBM 掘进过程中开展微震实时监测存在的困难与不足，对现有微震监测技术进行优化与改进，并在锦屏II 级水电站3#引水隧洞TBM 施工洞段开展微震实时监测。监测结果表明：（1） TBM 施工环境噪音复杂，但主要噪音特征明显，可通过建议的滤波方法有效滤除。（2） 围岩的微震活动和TBM 掘进及掘进速率具有明显的关系，TBM 掘进速率增加，围岩微震明显活跃；TBM 掘进速率降低，围岩的微震活动明显降低；微震平静期发生在TBM 检修期间，最活跃期发生在TBM 检修后掘进4～6 h。（3） 一些岩爆发生前，微震事件和能量释放在空间上由随机离散状态变得相对集中，在时间上微震事件的数量和能量有一个迅速增加的趋势；视体积有突增趋势，能量指数有突然下降迹象。（4） 在深埋隧洞TBM 掘进过程中进行微震实时监测，可以获得岩爆发生前的有效微震信息，获得岩爆发生前微震活动的演化特征与规律，为岩爆的发生提供较为准确的预警信息。因此，通过微震监测预测预报深埋隧洞TBM 掘进过程中岩爆的发生是可行的。

关键词：岩石力学；微震监测；岩爆预测；深埋隧洞；TBM；能量指数；锦屏II 级水电站

Abstract：According to the difficulties and shortcomings of real-time microseismic monitoring during tunnel boring machine（TBM） tunneling with overburden of over 2 000 m-thick hard and brittle rock mass，the traditional microseismic monitoring technology，used in the mines，is optimized and improved；and the new microseismic monitoring technology is utilized during the TBM tunneling in the diversion tunnel #3 of Jinping II hydropower station. The monitoring results show as follows：（1） The ambient noise is much and complex，but the main characteristic is clear during TBM tunneling；and it can be filtered through the proposed filtering method effectively. （2） There is an obvious relationship that microseismic activity increases with the increase in TBM tunneling rate between microseismic activity of surrounding rock mass and the TBM tunneling rate，vice versa. Microseismic activity is very weak during the period of TBM maintenance，but it becomes most active when TBM working lasts for 4–6 hours after TBM maintenance. （3） Before some rockburst occurred，distribution of microseismic events and energy release gradually convert from discrete to relatively concentrative in spatial domain，the number of microseismic events and the radiated energy increase rapidly in temporal domain；and apparent volume of surrounding rock mass has a sudden increasing trend；energy index has a sudden drop trend in the same time. （4） When microseismic monitoring is carried out during TBM tunneling covered with thickly hard and brittle rock mass，effective microseismic information can be acquired；the evolution characteristic and law of microseismic activity can be found and known；and more accurate early-warning information of rockburst can be provided. Therefore，it is possible and feasible to forecast the occurrence of rockburst by microseismic monitoring.

Keywords：Rock mechanics；microseismic monitoring；rockburst prediction；deep-buried tunnel；tunnel boring；machine（TBM）；energy index；Jinping II hydropower station