基于有限元模拟的盾构下穿对既有暗挖隧道的影响分析

Effects of Shield Undercutting on Existing Underground Tunnels Based on Finite Element Simulation

为探究盾构下穿施工过程对既有隧道沉降及内力影响,以北京市南水北调配套工程团城湖至第九水厂输水工程(二期)项目为实际工程依托,利用数值模拟的手段,建立三维盾构下穿既有隧道有限元模型,模拟盾构隧道下穿既有隧道的施工全过程,探明盾构隧道下穿过程对既有隧道的影响规律,得到既有暗挖隧道结构沉降及内力变化,并分析盾构掘进对既有隧道的扰动规律。此外,基于影响因素分析,探究两隧道间距离的影响。研究结论可为今后的相似工程提供合理的参考与借鉴。

In order to explore the influence of shield tunneling construction process on the settlement and internal force of existing tunnel,based on the water transfer project from Tuanchenghu to Ninth Waterworks(Phase II),a three-dimensional shield tunnel finite element model is established by means of numerical simulation,and the whole construction process of shield tunnel through existing tunnel is simulated.The influence law of the shield tunnel undercutting process on the existing tunnel is explored,the structural settlement and internal force changes of the existing tunnel are obtained,and the disturbance law of the shield tunneling to the existing tunnel is analyzed.In addition,based on the analysis of influencing factors,the influence of the distance between the two tunnels is explored.The research conclusions can provide reasonable reference for similar projects in the future.