深埋隧道工程高地应力影响下围岩稳定性分析

Surrounding Rock Stability Analysis for Deep Tunnel Engineering under High Ground Stress Impact

隧洞围岩稳定性分析目前主要采用的方法仍以经验判断为主,但高地应力区的深埋隧道,其围岩稳定性问题越来越突出,定量的分析评价显得非常重要。结合正在建设的引大济湟干渠工程中的深埋引水隧道,在分析隧道工程地质条件的基础上,分析隧道沿线地应力的分布规律,利用FlAC3D软件采用强度折减分析法对隧道围岩进行稳定性定量分析,并对围岩发生岩爆的可能性进行判别。结果表明,隧道埋深较浅时,岩土体以垂直自重应力为主;随着埋深增加,隧道的围岩稳定性逐步降低;在引水隧洞围岩的第十九至第二十六段有中等岩爆至弱岩爆,部分地段可能有较强岩爆。研究结果可以为工程施工提供技术支撑,也可为类似工程的建设提供借鉴。

At present, the stability analysis for tunnel surrounding rock still mainly relies on empirical judgment. But for high ground stress impacted deep tunnel, the surrounding rock stability issue is more and more prominent, quantitative analytical assessment appears to be very significant. Combined with constructing deep diversion tunnel of the water diversion from the Datong River to Huangshui River trunk canal project, on the basis of tunnel engineering geological condition analysis, has analyzed ground stress distribution pattern along the tunnel, using the FLAC3D software through strength reduction method analyzed tunnel surrounding rock stability quantitatively, and discriminated surrounding rock burst possibility. Results have shown that when the tunnel depth is shallower, rock and soil masses come under vertical deadweight stress, along with depth increasing, stability of tunnel surrounding rock gradually decreasing;surrounding rock sector Nos. 19 to 26 have possibilities of medium to weak rock burst, partial sectors may have stronger rock burst. The study can provide technical support for project construction, or reference for similar engineering constructions.