Simulation Calculation on Shield Tunnel under Different Construction Conditions

In order to study the influence on surface deformation of shield tunnel in different construction schemes,this paper simulates the following several aspects on the basis of establishing the finite element model of shield tunnel.Which include surface settlement due to excavation under different driving thrust force and different buried depth of tunnel,surface settlement under large-area load after excavation and the influence on shield tunnel deformation of underground water level changes after the tunnel construction completed.The result shows that shield thrust force will lead to the front range of surface soil uplifted and the thrust force is larger,uplift deformation and range are bigger.Under the same thrust force,uplift deformation and range of deeply buried tunnel surface are smaller.The rise of ground water level will lead to rebound deformation of the shallow layer soil and the surface rebound value of shield tunnel beneath the ground is smaller than no shield tunnel beneath the ground.When ground water level from the arch bottom of shield tunnel increased to the central place and vault place gradually,shield tunnel structure will appear displacement and lateral displacement,and the higher the water level,the greater the displacement value.