Study On Dynamic Response Of Orthotropic Saturated Foundation Under Moving Load

With the rapid development of highway,railway and other traffic construction in China,the number of vehicles is also increasing year by year.The long-term moving load has caused the settlement and damage of subgrade.There are a large number of saturated foundation soils in coastal cities in China.The mechanical properties of saturated foundation are poor,which is easy to cause many traffic engineering problems.Therefore,the research on the dynamic response of saturated foundation under moving load provides guiding significance for the development of engineering field.In this paper,the calculation model of plane strain of orthotropic saturated foundation is established,and the integral solution of dynamic response of saturated foundation is obtained.The coupling model of orthotropic saturated foundation and subgrade pavement is established by using ABAQUS finite element software,and the moving load is simulated by DLOAD subroutine.The dynamic response of orthotropic saturated foundation and road slab under moving load is studied.The main research work and research results are as follows:(1)The dynamic equation of plane strain problem of orthotropic saturated medium is derived in rectangular coordinate system.The integral solutions of displacement,stress and pore water pressure are obtained by using coordinate transformation and Fourier transformation,considering different soil drainage conditions and introducing displacement and stress boundary conditions.(2)The displacement,stress and pore water pressure of orthotropic saturated foundation under moving load are analyzed by ABAQUS finite element method.The results show that the orthotropic soil can better reflect the real behavior of subgrade and is closer to the reality;With the increase of soil depth,the maximum vertical normal stress of soil has an obvious downward trend.With the increase of load frequency,the maximum vertical displacement of soil decreases,and the pore water pressure along the depth direction decreases slightly.With the increase of moving speed,the vertical displacement of soil increases slightly,and the pore water pressure along the depth direction decreases significantly.(3)Based on the thin plate theory,ABAQUS finite element method is used to analyze the variation laws of the vertical displacement of orthotropic saturated subgrade pavement and the contact stress between pavement slab and subgrade under moving load.The results show that the maximum vertical displacement of pavement slab decreases with the increase of load frequency;With the increase of load moving speed,the vertical displacement of slab decreases slightly;The density of the road slab has little effect on the displacement of the slab,so the concrete density can not be considered in the project.The load has an obvious influence on the contact stress between the plate and the foundation;When the load frequency increases,the maximum stress increases;When the load moving speed increases,the maximum stress increases slightly.