米仓山深埋公路隧道岩爆预测与防治对策研究

岩爆是地下工程中一种严重的地质灾害,其破坏性巨大,是一项世界性的难题。为对岩体岩爆危险性进行综合分析,提高岩爆预测精度,本文从理论分析和现场测量两方面归纳了学术界隧道岩爆判据研究现状,建立了岩爆综合分析与预测系统框架。以米仓山公路隧道为例,结合数值模拟和岩爆综合分析与预测系统对其岩爆的趋势进行了预测。结果表明,隧道开挖后,隧道周边产生较大的应力集中,而且开挖使隧道周边围压迅速降低,产生较大的主应力差,导致围岩发生岩爆。预测米仓山隧道K49+175~K50+650段以弱~中等岩爆为主,最大埋深段附近为中等岩爆,局部可能发生较强烈岩爆。针对工程进展情况和岩爆情况提出了相应的防治对策。

Study on Prediction and Prevention of Rock Burst in Micangshan Deep Highway Tunnel

Rock burst is one of the critical geological disasters in the underground construction and a difficult problem in the world, which caused enormous destructivity for people and engineering. To analyze the risk of rock burst comprehensively and improve the prediction accuracy of rock burst, this paper summarizes the status of rock burst criterion study in literature from two view points: the theoretical analysis and engineering field observation and a comprehensive analysis and prediction system framework of rock burst has been established. Taking Micangshan highway tunnel as an example, the tendency of rock burst is predicted by using numerical simulation and the proposed prediction method. The study shows that there is a high stress concentration around the tunnel after its excavation, and at the same time, the confining pressure around the circumference decreases very quickly. As a result, a great difference of principal stress will be produced, causing the occurrence of rock burst in surrounding rocks. A weak~medium rock burst has been predicted in K49+175~K50+650 section of Micangshan highway tunnel. Medium rock burst is predicted to take place near the maximum depth section of the tunnel, because of the large depth, relatively strong rock burst is likely to occur locally. Accordingly, the appropriate prevention and control methods of rock burst are proposed.