爆孕育过程的微震源事件空间分形行为

Spatial fractal research of micro-seismic events associated with rockburst hazard

为了分析岩爆过程中微破裂事件的自相似特征,提出微震源事件空间分形计算方法.运用该方法,针对锦屏山水电站TBM及钻爆法2种不同开挖方式下,岩爆灾害孕育及发生所获得的微震信息进行研究.结果表明:对于深部岩体隧洞施工过程中发生的岩爆灾害,微震事件的空间分布是具有分形结构的;微震事件空间分形维数具有随着岩爆的孕育过程不断减小,当岩爆发生时达到最小值的特征;TBM开挖方式下的微震事件空间分形维数分布在0.6~1.8的范围内,钻爆法开挖方式下分布在1.2~2.0的范围内;微震事件空间分形维数与微震能量释放之间表现出明显的反比例关系.

A fractal calculation method was proposed in order to analyze the self-similarity of the spatial distribution of micro-seismic events during the development of rockburst hazard.The proposed method was used to analyze the fractal behaviour of micro-seismic events during the preparation and germination process of rockbursts that occurred in deep tunnels of Jinping mountain hydropower station,which was induced by the excavation of the tunnel-boring machine（TBM）and the drill-and-blast method（DBM）.The spatial distribution of micro-seismic events during the evolution of rockburst displayed fractal structure.The daily spatial fractal dimensions of micro-seismic events decreased during the preparation and germination process of rockburst,and were reduced to the minimum value as rockburst occurring.The spatial fractal dimensions were 0.6-1.8 by TBM excavation and 1.2-1.0 by DBM excavation.There was a inversely proportional relationship between spatial fractal dimension and micro-seismic energy release.