基坑开挖对下卧隧道变形影响分析及合理加固范围研究

Influence of Foundation Pit Excavation on the Deformation of Underlying Tunnel and the Reasonable Reinforcement Range

在深圳市桂庙路快速化改造工程施工过程中,前海段下沉式隧道需要采取明挖基坑的方式长距离平行上跨既有的地铁11号线隧道,而基坑开挖会使下卧隧道产生结构变形和附加受力,从而影响隧道的运行安全。借助数值分析软件,对基坑施工过程进行动态模拟,对比分析了不同旋喷桩地基加固情况下基坑开挖对下卧隧道的受力和变形影响。在此基础上,提出了合理的地基加固宽度和深度,把地铁隧道变形控制在规定范围内。最后,通过对现场监测数据的分析,验证了所提地基加固方案能有效控制下卧隧道的变形,并为以后类似工程的设计与施工提供了借鉴和参考。

In the reconstruction project of Guimiao Road in Shenzhen City,the sinking tunnel needs to be excavated with cut and cover method,which parallels to the underlying metro Line 11 in a long distance,and the excavation of foundation pit may cause deformation and additional force of lining structure,resulting in the safe operation of subway tunnel.In this paper,with the help of numerical analysis software,the construction process of foundation pit excavation is simulated dynamically,the influence of foundation pit excavation in different foundation treatments on the stress and deformation of tunnel lining is analyzed.On this basis,the reasonable width and depth of foundation reinforcement are put forward.According to the analysis of field monitoring data,the proposed foundation treatment scheme is verified to control the tunnel deformation effectively,and can provide a reference for the design and construction of similar projects.