The Influence Of Pumping On The Deformation And Internal Force Of Subway Tunnel Caused By Logarithmic Sedimentation

The stratum settlement from groundwater pumping will cause damage to buried beams such as municipal pipelines,underground pipe corridors and subway tunnels.With time and pumping groundwater increasing,gradually aggravated damage will affect the safety.Based on the s-lnr semi-logarithm linear rule of regional stratum subsidence caused by pumping,this paper studies the influence of deformation and internal force of subway tunnel under the action of pumping stratum subsidence.By using the Fourier transform,the equivalent transformation of s-lnr settlement curve formula is carried out,and the mathematical formula of analytic solution for the deformation and internal force of shield tunnel under the action of logarithmic ground subsidence is deduced.At the same time,the finite difference method is used to derive the mathematical formula of the deformation and internal force of shield tunnel under the action of logarithmic stratum subsidence.MATLAB software was used to program and calculate the analytical solution and finite difference numerical solution obtained by the above two methods,and the results obtained by the two methods were compared.The numerical example shows that the analytical solution and the finite difference numerical solution have similar results with little error.By applying the derived analytical formula,the influence parameters of deformation and internal force of subway tunnel are analyzed by the control variable method.It is concluded that the slope of the curve reflecting the steepness of the subsidence funnel has the greatest influence on the deformation of the subway tunnel.The damage to shield tunnel can be reduced by lowering the gradient of settlement funnel.The finite element numerical software PLAXIS 3D was used to verify the analytical and finite difference solutions of the deformation and internal force of shield tunnel under the action of logarithmic ground subsidence.The finite element software PLAXIS 3D was used to establish the numerical model.By using numerical software to simulate the whole process of pumping subsidence,the subsidence deformation of subway tunnel is obtained.By comparing and verifying the data obtained by the three methods,it is concluded that the results obtained by the three methods are almost the same,and their errors meet the engineering requirements.On this basis,this paper further studies the influence of tube well precipitation on shield tunnel.In other words,when the pumping well is at a certain distance from the shield tunnel,the pumping causes the influence of ground subsidence on the shield tunnel.The influence of pumping subsidence on shield tunnel is obtained by finite difference method.The finite difference numerical solution of the deformation and internal force of shield tunnel under the action of logarithmic ground subsidence is derived.The finite element numerical software PLAXIS 3D was also used to establish the numerical model and conduct numerical simulation verification.The results show that the two conclusions are consistent,which further verifies the correctness of the proposed method.