深部岩体隧洞岩爆灾害影响因素分析

Analysis of influence factor associated with rockbursts in deep,hard rock tunnels

深部岩体隧洞施工过程中频发的岩爆灾害时常会造成大量的人员伤亡以及巨大的财产损失。基于某水电站4条引水隧洞开挖过程中的大量的岩爆实例,以数值运算为主要研究手段,从能量的角度出发对影响岩爆灾害发生的关键性因素进行了研究,结果表明:相同长度的隧洞开挖过程中随着单循环开挖步长的增大,微震能量释放值不断增大,岩爆的发生频次具有增加的趋势;当开挖速度控制在合理范围内时,围岩稳定性可以得到有效控制,当其突破到临界状态以上时,岩爆的发生频次具有显著增加的特征;在一定埋深范围内随着埋深的增加,岩爆发生的频率、强度具有明显增加的趋势;上述研究结果可以为高地应力条件下地下隧洞开挖过程中岩爆的预测与防治提供合理的科学依据。

Rockbursts in tunnels can be a significant hazard. Based on a large amount of micro-seismic information and hundreds of rockbursts that occurred in four deep headrace tunnels at a hydropower station in Sichuan province, China, we combined numerical calculation with micro-seismic monitoring in order to study the evolution processes of rockbursts. The achieved results are as follows： the excavation scheme, speed, and buried depth can affect the stability of the surrounding rocks in deep, hard-rock tunnels during construction. As the excavation step length, speed, and buried depth increase, the micro-seismic energy rises, and so do the frequency and intensity of rockbursts. The results can provide reasonable and scientific basis for prediction and prevention of rockbursts during underground tunnel excavation under high geostress.