岩爆灾害过程中能量分布的自相似特征分析

Analysis on self-similarity characteristics of energy distribution associated with rock burst disasters

基于四川省凉山自治州境内的锦屏二级水电站深埋隧洞钻爆法(DBM)及隧道掘进机(TBM)施工过程中的微震实时监测数据及大量不同等级的岩爆实例,针对上述两种不同开挖方式下岩爆过程中的微震事件展开了微震能量分布的自相似特征及分形行为研究。获得如下研究成果:深部岩体隧洞岩爆灾害过程中的微震事件是具有能量分形分布特征的,并且表现出良好的自相似性;根据能量分形维数可以对诱发岩爆灾害的开挖方式进行区分,钻爆法开挖方式下的能量分形维数小于0.2,而TBM过程中的能量分形维数均大于0.3;相同开挖方式下不同等级岩爆过程中的微震事件能量分形维数值与岩爆等级具有正比关系。上述研究结果对高地应力条件不同开挖方式下岩爆动态预警体系的建立具有重要的指导意义。

This paper describes a fractal calculation method for examining the self-similarity of energy distribution of the micro-seismic events produced by rock bursts in drill-and-blast method（DBM） excavation and tunnel boring machine（TBM） excavation, using micro-seismic data collected during the construction of the deep tunnels with an overburden layer of 1500-2500 m at the Jinping-II hydropower station in Sichuan, China. Results show that fractal behaviors and good self-similarity are two major features of the micro-seismic energy distributions in the evolution of immediate rock bursts. The energy fractal dimensions of the DBM and TBM excavation rock bursts are less than 0.2 and greater than 0.3 respectively. Generally, weak rock bursts have lower energy fractal dimensions. Micro-seismic energy fractal dimensions are useful for developing a warning system and reducing the risk of rock bursts during construction.