Analysis Of The Reasonable Step Of Dismantling Shoring Of Large-span And Small-interval Twin Tunnel

In recent years, with the rapid development of China’s transportation construction and the increasing levels of the underground engineering technology, we have successfully built a complex of shallow large span tunnels。However, the mechanical behavior of the tunnel is generally limited to the excavation process, such as controlling the tunnel surface subsidence in the excavating, theconstruction process, the stability of the tunnel and the reinforcement measures.The timing of removing the temporary support, and the step of the dismantling, do a large impact on the safety of the tunnel structure and the stability of the surrounding rock in the process of constructing. This article is based on this to expand the study.In the background of Shenzhen Qilin Mountain Tunnel project, this paper analyzes the factors which impact the removing of the tunnel temporary support. and then analyze the main factors to find out the intrinsic link and laws between the main factors. The research topics include the following two aspects:(1) Using the finite element method to simulate the constructing program of the complex large cross-plane tunnels in the shallow soft surrounding rock and then put forward the reasonable order of the removing of temporary support by the plane strain model.(2) Using the three-dimensional finite element model to simulate the constructive process of removing the temporary support and then put forward a reasonable step for removing the temporary support one time after comparing analysis.(3) Analyzing the site monitoring results and the deformation of the rock convergence during the tunnel construction and then comparing the results with the results of the numerical simulation, to provide a theoretical basis and technical guidance for the safety and support parameters of the adjustment of tunnel constructing.