Study Of Three-dimensional Dynamic Response Of Orthogonal Anisotropic Saturated Foundations Under Moving Load

The current rapid development of China’s transportation industry,and the existence of a large number of saturated soils in coastal soft soil areas,its natural water content,high compressibility,low bearing capacity and other characteristics easily lead to many traffic engineering problems,it brings great challenges to the construction of roadbeds in soft soil areas.Accurate grasp of the dynamic response of saturated soft ground caused by vehicle loading has important scientific research value and engineering application value.This study has important theoretical support for improving the design and construction of road base pavement engineering and preventing and mitigating road disasters.In this paper,a three-dimensional dynamic response mechanics model of orthogonal anisotropic saturated foundation under vehicle resonant load is established by introducing Biot porous medium theory,and the partial differential equation of dynamic response in right-angle coordinate system is derived.The integral solution of the orthogonal anisotropic saturated foundation at any point and at any time in its spatial range is obtained by combining the initial conditions and boundary conditions through coordinate transformation and Fourier transformation.Based on the ABAQUS finite element software combined with the soil parameters provided by the field construction example,the orthogonal anisotropic saturated foundation 3D model and the saturated foundation overlay infinite slab 3D model are established respectively for numerical analysis,and the DLOAD user subroutine is written in FORTRAN language to simulate the moving horizontal load,based on the theoretical analysis and finite element simulation the main work and research results are as follows:(1)The partial differential equation of three-dimensional stress problem in orthogonal anisotropic saturated medium is derived by introducing stress-strain relationship and equation of motion,and the integral form solution of dynamic response of saturated soil at any point and at any time under the action of moving load is obtained;based on the theory of thin plate,a three-dimensional mechanical model of orthogonal anisotropic saturated foundation with right-angle coordinate system is established.The three-dimensional mechanical model of road base pavement over an infinite elastic plate is established based on the thin plate theory,and the integral form solution of the dynamic response of plate and foundation under the action of moving load is derived by using coordinate transformation and Fourier transformation,and the correctness of the theoretical analysis is verified by degradation.(2)Based on ABAQUS software,an orthogonal anisotropic saturated foundation 3D model is constructed,and the DLOAD subroutine is embedded to simulate the vehicle load and derive the nodal data at any point at any time.The theoretical analysis results are compared with the finite element simulation results to verify the correctness of the finite element model.The changes of vertical displacement,stress and pore water pressure of orthogonal anisotropic saturated foundation under the action of moving load are simulated and analyzed by finite element software.(3)A three-dimensional model of an orthogonal anisotropic saturated soil overlying elastic plate was constructed by using ABAQUS for data simulation,and the vertical deflection of the plate and the contact stress between the plate and the roadbed were studied by adjusting the soil parameters,plate parameters and load parameters,etc.The path data were selected by combining the displacement cloud map,and the dynamic response of the infinite thin plate overlying the saturated foundation was summarized by analyzing the displacement and stress curves.