The Study Of Surface Subsidence Caused By Shield Construction

Due to the diversity of the soil layer, the actual site operation is uncertainty in Subway tunnel shield construction, it would inevitably produce disturbance to the soil in practical engineering, it would result the surface settlement and affect the normal use of the surrounding buildings and underground facilities when settlement is too large.So the research of shield construction to the influence law of ground surface subsidence has great significance to predict which measures to adapt to avoid the surface deformation.In this paper, on the basis of reading related documents and materials,through to the studied of shield construction to the deformation laws of surface subsidence,according to the study of shield construction in the process of the surface subsidence mechanism and influence factors of surface subsidence, sum up the deformation law of development of surface subsidence.And simulating the wear of the tunnel excavation process by using ABAQUS software, researching the different tunnel buried depth, different shield boost pressure, different grouting thickness variable factors on the influence law of ground surface settlement in shield excavation process.Then, simulating the wear of the tunnel excavation process base on Gedadian in Hefei subway station to Wang Hu between city station in tunnel construction under shield as practical engineering background;According to the practical engineering geological conditions, choose the parameter modeling, computational and analysis deformation of the ground settlement caused by shield tunneling at different stages,compared and analyzed the model calculation results and the actual monitoring results.The following conclusions:(1)According to the engineering background, ABAQUS software was used to simulate the shield construction in the excavation of the tunnel under the process of calculation results which compared with the practical engineering monitoring, the deformation law is roughly the same,model is reliable.(2) The analysis can be found by calculation, the greater the buried depth of tunnel, surface subsidence value is smaller,it will increase with the buried depth, the scope of its impact.due to its extension on the scope of its horizontal sedimentation characteristics.(3) The advance of shield tunnel excavation face pressure to influence on surface subsidence, and reasonable control of boost pressure to ensure it with the value of soil pressure control in a certain range, can effectively reduce the disturbance of soil, so as to avoid excessive deformation on the surface of the earth(4) The thickness of shield tunnel grouting on the control of subsidence of the earth's surface is relatively obvious, the thickness of grouting, the greater the formation damage is less, the surface subsidence will smaller.