当金山隧道区域地应力特征分析与应用

The Regional Geostress Characteristics Analysis and Application in Dangjinshan Tunnel

研究目的:敦格铁路当金山隧道位于兴蒙褶皱系与祁连山褶皱系之间的阿尔金断隆,隧道埋深大,地质条件复杂,高地应力是隧道施工中的主要地质问题。通过对隧道区域地应力特征分析,分析预测隧道施工中与高地应力有关的地质问题。研究结论:(1)当金山隧道区地应力高,以水平应力为主,属高地应力区;(2)根据切向应力准则判断,隧道施工中埋深较大地段较完整的云母石英片岩、花岗岩有发生轻微岩爆的可能,绿泥石英片岩发生岩爆的可能性小;(3)根据隧道区的地应力特征及岩性特征分析,断层破碎带(尤其是F5断层)岩质软弱,在施工中有发生较大变形的可能,其他地段发生变形的可能性较小;(4)本文采用的隧道地应力分析与评价方法及与高地应力有关主要地质问题的分析,对类似工程具有参考和借鉴意义。

Research purposes： The Dangjinshan Tunnel of Dunhuang - Golmud Railway, is located in the Ahyn fault system which is between Xing - Meng fold system and Qilian Mountain fold system. The tunnel with high buried depth will encounter a series geological problems such as high geostress, complex geological condition, etc. Through studying the geostress characteristics in this region, the geological problems related to the high geostress can be analyzed and predicted in the tunnel construction. Research conclusions： （1） The tunnel is located in the region with high geostress and the horizontal stress is the maximum principal stress. （2） According to tangent stress principle, the slight rock burst would happen along the deeply -buried sections with integrate mica - quartzose schist or granite and scarcely happen along the sections with chlorite-schist. （3） Based on analysis of the geostress and lithology characters, the large deformation may happen in the fault fracture zone （especially Fs ） with soft rock and in other regions the deformation may not happen. （4） The geostress analysis, evaluation method and analysis of engineering geological problems introduced by high geostress in the paper have reference significance for other tunnel construction.