Study On Stratum Deformation Control Technology Of Shield Tunnel Crossing Urban Road

With the rapid development of urban rail transit construction,there are more and more shallow underground tunnel engineering.Due to the shallow buried depth of the tunnel,tunnel construction can affect the surrounding environment and the stability of the underground structure should be focused on.How to predict and control the ground deformation and protect the tunnel safety become the key and difficult points of this kind of engineering.Therefore,it is very important to effectively control the ground settlement and protect the safety of tunnel structure.This thesis takes the subway tunnel construction section as the engineering background and studies the safety of the construction of the ultra shallow shield tunnel paralleled underpass municipal road.Based on the investigation of domestic and foreign literature,the methods of numerical calculation and field measurement are adopted to study the deformation control technology of ultra shallow shield tunnel under municipal road.The influence of ultra shallow shield tunneling on stratum deformation and the influence of ground vehicle dynamic load on stratum deformation and tunnel segment safety are analyzed.Shield construction parameters are optimized,deformation control standards are established and corresponding engineering measures are proposed.The main research contens are as follows:(1)The influence of general tunnel construction on stratum deformation and the influence of dynamic load on tunnel structure safety are analyzed,and reference for optimizing construction parameters of ultra shallow shield tunnel and formulating ground deformation control standards are provided.(2)Using numerical simulation to analyze the influence of different buried depthes of tunnel and different chamber pressures of shield machine on ground deformation.(3)Using numerical simulation to analyze the influence of the vehicle speeds and the concrete strengthes on the dynamic response of segment structure.(4)Numerical simulation is used to compare pre-grouting reinforcement method with surcharge back pressure schemes.(5)According to the settlement control standard of subway tunnel and the measured data of surface deformation in China.According to the results of numerical simulation,the settlement control standards of ultra shallow tunnels under municipal roads are formulated,the shield construction parameters are optimized,and the corresponding engineering countermeasures are made.