基于微震监测的岩爆预警方法研究

Rockburst Early Warning Method Based on Microseismic Monitoring Technology

以锦屏二级水电站深部隧洞为研究对象,采用微震监测技术,对卸荷作用下的深埋隧洞微震活动性时空分布规律及时序规律展开研究。基于现场岩爆记录与微震监测结果比对,探讨了岩爆与微震活动间的内在联系并提出深埋隧洞岩爆监测预警方法。监测结果表明:岩爆发生前具有明显的微破裂前兆特征,微震事件由空间无序分散逐渐向有序集中的自组织演化,微震参数包括累计事件数、微震能量密度、累积视体积及能量指数的异常变化均可作为岩爆预警指标。基于研究结果,提出高地应力条件下深埋隧洞岩爆监测预警方法,预测准确率达到80.6%,实用效果较好并为此类地下工程的岩爆预测提供借鉴意义。

In order to reveal the internal relationship between rockburst and microseismic activities and to propose the monitoring and early warning method of rockburst in deep tunnel,the deep-buried tunnel of Jinping II Hydropower Station is taken as an example.The spatiotemporal distribution and time sequence characteristics of microseismic activities in deep-buried diversion tunnel under unloading are analyzed in detail with the aid of the microseismic monitoring technology.The monitoring results show that the rockburst has obvious precursory characteristics of micro-fracture before the occurrence of rockburst.Microseismic events gradually evolve from spatial disordered dispersion to ordered set,and the abnormal changes of the microseismic indicator,i.e.,cumulative events,energy density,cumulative apparent volume and energy index,could be regarded as an early warning index of rockburst.A rockburst monitoring and early warning method for deep and long tunnels under high ground stress is then proposed,and the corresponding predicted accuracy is demonstrated as high as 80.6%.The results in this study show good effects in practical application and provide an important reference for the prediction of rockburst in of the deep underground engineering.