大侧压力系数高地应力条件下V级围岩隧道开挖的变形规律研究

Study on the Tunnel Excavation Deformation in 5th Grade Surrounding Rock under High Stress Condition with high lateral pressure coefficient

采用相似材料模型的试验方法,对高地应力条件下V级围岩隧道开挖变形规律进行研究。对模型加载完成后,测得V级围岩相似材料中围岩的水平应力为垂直应力的2倍,即侧压力系数为2,可以用来模拟高地应力。在高地应力条件下V级围岩隧道开挖过程中,隧道周边围岩应力随着隧道的开挖,围岩应力不断释放减小,其中围岩水平方向的应力释放速率较垂向应力释放速率快;同时衬砌拱腰上的压应力随隧道开挖不断增大,衬砌拱腰上压应力最大,拱顶应力由压应力逐渐变为拉应力。在整个隧道的开挖过程中隧道衬砌最大变形出现在隧道中间段,衬砌拱顶向外变形最大值为0.11 mm,拱腰向内变形最大值为0.7 mm。

This paper studies the tunnel excavation deformation in 5th ground rock under high stress conditions using a test method of similar material model.After the model is loaded,the measured horizontal stress in the sur-rounding rock of similar material is two times the vertical stress,i.e the lateral pressure coefficient is 2 which means that stress can be used to simulate the high stress conditions.During the tunnel excavation in 5th surrounding rock with high stress conditions,with the excavation of the tunnel surrounding rock,the rock stress is relaxed continuously,where stress relaxation in the horizontal direction is faster than in the vertical direction,mean-while the compressive stress on the lining of tunnel excavation increases with excavation,the maximum compressive stress occurs at the waist lining and the arch stress changes to tensile stress.In the tunnel excavation,maximum deformation in tunnel lining occurs in the middle section of the tunnel,Max.arch outward deformation is 0.11 mm,maximum arch waist inward deformation is 0.7 mm.