不同工法下连拱隧道施工阶段围岩稳定性分析

Analysis of surrounding rock stability in construction of multi-arch tunnel under different construction methods

双连拱隧道开挖断面较大,且两边拱圈共用一个中隔墙,导致双连拱隧道施工时经常出现安全事故。通过分析不同的双连拱隧道施工方法下围岩的变化,可以预测围岩的应力应变,指导施工。中导洞施工方法开挖扰动频率小,有利于机械化施工,它是双连拱隧道较常采用的施工方法之一。但是中导洞施工法对地质要求较严格,所以三导洞施工法也有其必要性。利用FLAC^(3D)模拟两种不同的工法条件下隧道施工阶段围岩的稳定性,发现两种工法施工时中隔墙顶端位移最大,施工时需重点关注。

Double-arched tunnel excavation section is larger,and the two side arches share a middle partition wall,which often leads to safety accidents during the construction of double-arch tunnels. By analyzing the variations of surrounding rock under different construction methods for double-arched tunnels,it is possible to predict the stress and strain of surrounding rock in the construction of multi-arch tunnels in advance and guide the construction.The construction method of the middle guide tunnel has a small number of excavation disturbances and is conducive to mechanized construction.It is one of the commonly used construction methods for double-arch tunnels.However,the guiding tunnel construction method has strict geological requirements,so the three-guide tunnel construction method also has its necessity.The FLAC3 Dwas used to simulate the stability of the surrounding rock under the two different construction conditions.It is found that the displacement of the top of the partition wall is the largest during the construction of the two methods,and the construction should be focused.