不同施工顺序对偏压连拱隧道结构稳定性的影响分析

采用弹塑性三维有限元数值模拟计算分析的方法，对桐油山隧道浅埋、偏压地段结构稳定性进行了模拟分析，主要模拟了不同施工顺序对围岩及支护结构稳定性的影响，重点对连拱隧道整体衬砌中的薄弱环节——中墙进行了分析。结果表明：不管采用哪一种施工顺序，中墙均受偏压荷载的作用并向埋深较浅侧倾斜。但是先开挖埋深较深一侧时，中墙的受力和倾斜均较小，优于采用先开挖埋深较浅一侧的施工顺序。其计算结果也为同类隧道的施工提供了一些参考。

Analysis on the Structure Stability of the Unsymmetrically Loaded and Connecting-arch Tunnel Caused by Different Construction Orders

By adopting the calculating analysis method of elastic-plastic three-dimensional FEM numeric simulation, this paper makes a simulation analysis on the structure stability of the shallow cover and unsymmetrically loaded parts in Tongyoushan tunnel, mainly simulates the effects caused by different construction orders on surroundings and supporting structure stability, and it centers on the analysis on the weak part, the midwall in the lining of the connecting-arch tunnel. The result shows that on matter which construction order is adopted, the midwall will always slant to the side of shallower depth of cover. However, when the side of deeper depth of cover is first dug, the received strength and gradient on the midwall will be both smaller, which is superior to the usual construction order with the side of shallower depth of cover dug first. The calculating result also gives some reference to the similar tunnel construction.