Funnel Curve Of Land Subsidence Caused By Groundwater Withdrawal And Influence Of Land Subsidence On Tunnel

Regional land subsidence caused by groundwater withdrawal has become a worldwide geological disaster.Monitoring and predicting the amount of land subsidence is the main content of land subsidence research.According to the formula of land subsidence curve through the center of funnel,not only can the continuous8 distribution law of settlement value be determined,but also more comprehensive settlement information can be obtained than the scattered monitoring value.And it is more simple and practical than numerical calculation.The previous s-ln r linear relation of regional land subsidence has some deviation in calculating the settlement value of the central area of the settlement funnel,so it needs to be improved.In this paper,based on the idea of vertical stratification and horizontal differentiation,the theory of soil small deformation is introduced,the single-layer and multi-layer partial differential control equations are established,the formula of land subsidence curve through the center of the funnel is solved for single well pumping,and the formula of ground settlement curve through the center of the funnel is deduced by superposition principle.It is verified by 7 typical regional ground subsidence funnel calculation examples at home and abroad that the settlement curve formula fits well with the monitored values and can accurately calculate the settlement values of the whole region including the central area of the leak,and the correlation coefficients are above97%,which proves the feasibility of the formula.In addition,the ground subsidence in follow-up studies of s-ln r linear equation applied to real engineering,pumping in strata subsidence has a bad influence on tunnel and other ground beam,existing analytical method only consider pumping in stratum settlement of metro tunnel,the influence of deformation and internal force did not consider the train load and strata subsidence and at the same time to the influence of the tunnel.Aiming at this deficiency,the theoretical solution of tunnel internal force and deformation under the combined action of pumping and train load is studied.Based on Winkler beam theory of elastic foundation and logarithmic settlement curve formula,the theoretical solution of internal force and deformation of tunnel under the combined action of ground settlement and train load is derived by Fourier series method.The ABAQUS software is used to establish the three-dimensional numerical model of tunnel and stratum,and the effect of groundwater withdrawal and train load are applied to obtain the internal force and longitudinal settlement deformation of tunnel structure under the combined load of both.The results of theoretical solution and numerical solution are in good agreement,which verifies the correctness of theoretical solution.Further comparative analysis shows that the influence of ground subsidence caused by groundwater withdrawal on the tunnel is much greater than that of train load,indicating that controlling groundwater withdrawal around the tunnel is of great significance for protecting the tunnel.