深埋隧洞微震活动区与岩爆的相关性研究

Study of relativity between rockburst and microseismic activity zone in deep tunnel

基于锦屏二级水电站深埋引水隧洞和排水洞大量微震监测数据及上百个不同等级岩爆实例,研究了深埋隧洞微震活动区与岩爆之间的关系。研究结果表明:(1)微震活动分布范围主要介于掌子面后方3倍洞径至前方1.5倍洞径之间,而岩爆高发区位于掌子面后方3倍洞径以内,表明岩爆高发区与微震事件主要分布范围相吻合;(2)隧洞工程岩爆潜在风险重点关注区域是掌子面后方3倍洞径已开挖范围,以及掌子面前方1.5倍洞径施工范围;(3)微震事件及岩爆分布呈区域性集结特点,其中一部分岩爆发生于微震事件集结区内部,另一部分岩爆发生于微震事件集结区边缘,这是岩体破坏过程中所固有的现象,与微震事件集结区边缘局部应力集中密切相关。

Based on a large amount of microseismic monitoring data and hundreds of rockbursts with different intensities occurring in the deep diversion and drainage tunnels of JinpingⅡhydropower station,relativity between rockburst and microseismic activity zone is studied.The conclusions are drawn as follows.（1） Microseismic activity mainly ranges from 3 times the tunnel diameter behind working face to 1.5 times ahead;and rockburst high-risk zone lies in the region as large as 3 times the tunnel diameter behind working face.Therefore rockburst high-risk zone is greatly in accordance with the main microseismic activity zone.（2） Potential rockburst high-risk zones in tunnel project are highly localized in the region already excavated as large as 3 times the tunnel diameter behind working face and the region under construction as large as 1.5 times the tunnel diameter ahead of working face.（3） Seismic events and rockburst distribution are characterized by regional aggregation.Some of them happen in the aggregation region of seismic events.Others happen on the edge of aggregation region of seismic events.That is an inherent phenomenon in the failure progress of rock mass and closely related to local stress concentration on the edge of aggregation region of seismic events.