Abstract：Research purposes： The Dangjinshan Tunnel of Dunhuang-Golmud Railway, is located in the Altyn 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 F5) 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.

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