地表水平及倾斜下隧道变形受力特性对比分析

地表倾斜是傍山隧道经常遇到的情况，给施工带来极大的困难。因此，基于有限元原理建立了地表水平和地表倾斜的两种模型，通过对比分析地表水平和地表倾斜情况下的围岩变形受力、围岩塑性区分布、支护结构受力情况，研究地表倾斜下隧道的变形受力特性。结果表明：地表倾斜下的围岩和支护结构受力均不关于隧道中心线对称，且围岩水平位移表现为顺坡方向，围岩应力在深埋侧左墙脚和浅埋侧右拱腰部位产生应力集中，深埋侧左墙脚和浅埋侧右拱腰弯矩增大明显，塑性区分布呈“不对称蝴蝶”形分布。

Comprison of Tunnel Deformation and Stress under Horizonal Ground and Declined Ground

Slope surface is often common in tunnel entrance section adjacent to mountain, which brings great difficulties to the construction. Simulation models were established under horizonal ground and declined ground to study characteristics of deformation and stress under declined ground by compari- son of surround rock deformation, stress, plastic zone, and internal force of support. The results showed that： deformation and stress is unsymmetrcjal to the tunnel central line; surrounding rock horizontal dis- placement parallel with the declined ground; there is stress concentration in the deep-buried side of the left wall foot and in the shallow-buried side of the right hance; plastic zone was asymmetric butterfly - shaped distribution.