Study On The Stratum Deformation And The Influence Of Adjacent Bridge Piles Due To Tunnelling With Shallow Tunnels Construction Method

With the development of our country urbanization, subway has become an important way to solve the problem of the traffic congestion,scarcity of land resources and environmental pollution. Confined by the tendency of lines and undergrounds paee, many subways are built along city roads, running through pile of undations of the oveprasses. foundation. Subway projeets inevitably go from the inferior and sides even at position of these pile foundations sometimes. However, tunnel constructions will disturbe soil and bring distortion and displacement which get piles and around soil to occur interactively and create piles' redundant deformation and internal force, which aeffct the normal operation and saefty of the overpass.Researching the effect of piles near subway project by excavation for shallow tunnels has become an important issue needed to be resolved in subway engineering construction.In order to research stratum deformation induced by the tunnel construction and the effect of tunnel construction on adjacent bridge piles,we study it with the method of theoretical analysis, numerical calculation and on-site measurements. The paper's primary content and result as follows.(1) Bridge piles is studied from three-dimensional effect, The basic principles of the tunnel and the stratum deformation theory of tunnel construction,and the impact theory of tunnel construction on the bridge piles.(2) Combineing with specific examples of Daxing line's project and using the Midas /GTS numerical simulation software to establish the mechanical model,and compareing simulation results with the measured datas, the author summarize the variety law of surface subsidence, settlement and axial force of piles.(3) Using two-stage analysis method, the author analyzes two important factors of the loss rate of stratum and the distance between piles and tunnels which have different effect for different types of piles. Three control measures of subway tunneling adjacent Piles are put forward:subway construction measures, soil reinforcement measures and bridge framework measures.