基于动力学机理的施工期岩爆主动防治初探

Initiative control of rock-burst under excavating based on the dynamic mechanism

采用Laplace变换方法得到了静水应力场中爆破开挖时初始地应力动态卸载所诱发的围岩振动,并和爆炸荷载所诱发的围岩振动进行了比较.结果表明,初始地应力动态卸载扰动是整个开挖扰动的重要组成部分,在一定的地应力水平下甚至有可能超过爆破扰动成为开挖扰动的主要成分.基于此,提出了以优化钻爆网络和起爆顺序为核心的爆破开挖扰动控制方法,该方法可以同时减小爆炸荷载引起的扰动和地应力高速卸载所引起的振动,可从一定程度上实现对岩爆的主动控制.二滩水电站和瀑布沟水电站地下厂房的开挖实例证明了此方法的有效性和实用性.

Adopting the Laplace transform method, the dynamic stress stimulated by in-situ stress transient unloading in hydro-static stress field was calculated, and the characters of the vibration of surrounding rock caused by dynamic unloading of in-situ stress were studied and compared with that of the vibration induced by blasting load. The results indicate that In-situ Stress Dynamic Unloading Disturbance （ISDUD） is an important part of Excavation Disturbance （ED）, and the ISDUD could exceed the blast load-induced disturbance and become the dominant component of ED under certain level of geo-stress. Based on this conclusion, the idea of initiative control on rock- burst during the excavation process under high geo-stress condition was presented, and the primary practical measures of minimizing the ED and preventing rock-burst were advised, the core of which was optimization of initiation network and procedure. Application of this method in excavation process of underground powerhouse of Ertan and Pubugou projects verified the availability of it.