浅埋大断面隧道在初期支护下的稳定性数值分析

Numerical Simulation for the Large Section Tunnel Under the Primary Lining

浅埋大断面隧道由于明显的空间效应以及断面面积、高跨比、跨度、埋深、施工方法等因素的不同,隧道在围岩和支护结构的破坏模式上常出现较大的差别。本文通过对宁波大榭管廊浅埋大断面隧道进行有限元方法,模拟经济简单的中隔墙台阶法和上下台阶法,对拱顶沉降及初次支护的受力状态进行分析,并与实际监测数据进行对比分析,得出较为一致的结果。最后,通过对比分析,得出中隔墙台阶法能有效减少拱顶沉降及初次支护应力,各项变形指标均在规范之内。本研究对此类隧道的施工与设计有一定指导意义。

Due to its many complicated factors of the large section of shallow buried tunnel, So In this paper, the finite element method is used to simulate the Ningbo Daxie large section pipe gallery tunnel which is shallow buried. It is used that the state of method of partition steps and benching tunneling method , to analyze the vault subsidence and the stress of initial support of surrounding rock. The finite element method simulation was in accordance with the results of actual monitoring data. Finally, it is concluded that the application of method of partition steps could reduce the vault subsidence and the stress that is supported the first time, and the deformation index is within the specification. This study has certain guiding significance to the design and construction of such kind of tunnel.