| Displacement and deformation of city subway tunnels need to be strictly controlled. The excavation will cause subsidence of the surrounding soil, if the excavation process can not use reasonable excavation scheme, adjacent existing subway tunnel will be excavated pit can not affect the normal operation. In this paper, the use of Shanghai Tao Pu Road -Zhen Nan Road beneath the flyover really deep excavation, carried out the double impact of the construction pit lying und er the existing double shield tunnel (Shanghai Rail Transit Line R11) analysis and research, The main contents and conclusions are as follows:(1) From the enclosed structure, surface subsidence and upheaval in the bottom etc. introduced factors and calculation methods of pit deformation; from the opposite position, soil environment, groundwater, enclosed structure, excavation and construction technology.It analyzes the impact of the construction pit near the underground tunnels; It describes the construction pit deformation caused by tunnel correlation calculation theory.(2) Based Shanghai Tao Pu Road-Zhen Nan Road Interchange Area B beneath excavation instance, Using ANSYS finite element software, based on certain assumptions, the establishment of three-dimensional numerical model, Model is considered supporting structure and foundation pit excavation process, numerical simulation of excavation construction near the existing shield tunnel.(3) Numerical simulation results show that:In Tao Pu Road-Zhen Nan Road beneath the overpass area B Foundation construction process, the maximum vertical displacement of metro shield tunnel 17.589mm, maximum lateral displacement of 4.0mm, less than 20mm; Metro Shield Tunnel Segment (C50) the maximum tensile stress 2.46MPa, the maximum compressive stress is 7.05MPa, It meets all the requirements of concrete tensile, compressive strength. So Shanghai Tao Pu Road-Zhen Nan Road beneath overpass construction pit area B not a big impact to the rail line R11. |
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