Research On Stability And Displacement Of The Slope Lacustrine Soft Soil Under Embankment Load

As the growing scale of highway construction in our country in recent years,the highway will inevitably pass through some special foundation,such as slope lacustrine soft soil foundation and so on.Slope lacustrine soft soil foundation has inclined slopes in both cross section and longitudinal direction of the road,so the formation of the soil layer is more complex and the soil has strong spatial variability.At present,study on the deformation and stability of slope lacustrine soft soil under embankment load,most scholars thought these researches should be studied as a plane strain problem,although in some reaearches,three-dimensional finite element numerical models were built,but in these models the longitudinal length were unit length,so these models can not study the affect of the longitudinal slope on the deformation and stability of the slope lacustrine soft soil foundation.In view of this,based on a Yunnan expressway engineering,a two-dimensional and a three-dimensional finite element model of the slope lacustrine soft soil foundation under embankment load are established by the numerical analysis software ABAQUS,to analyze the deformation characteristics of slope lacustrine soft soil foundation under embankment load and compare the simulation results with the measured results to verify the accuracy of the model.Based on finite element strength reduction method,several three-dimensional and two-dimensional numerical models of the slope lacustrine soft soil foundation under varied cases are estabilished to study the effect of influence factors on its stability.At last,the effect of influence factors on the deformation of the slope soft soil foundation under the embankment are studied by orthogonal test.The main research results are as follows:1.Two-dimensional and three-dimensional numerical models of the slope lacustrine soft soil foundation under embankment load are established,combined with field data,preliminarily demonstrate that slope lacustrine soft soil foundation should be studied by the three-dimensional numerical model,baesd on this,the settlement and lateral displacement deformation characteristic of the slope lacustrine soft soil foundation are analyzed.2.Based on strength reduction finite element method,the soft soil thickness,miscellaneous fill thickness,slope in the cross section and slope in longitudinal direction of the road are regard as the main factors of the stability of lacustrine soft soil foundation,using the numerical simulation method to study the effect of influence factors on the three-dimensional and two-dimensional stability of slope lacustrine soft soil.3.Using nonlinear finite element method to establish four foundation cases under embankment loads,including horizontal lacustrine soft soil foundation,horizontal common foundation,slope common soil which the surface is flat and slope lacustrine soft soil which the surface is flat,discuss the settlement of foundation surface and lateral displacement of foundation toe in every case.4.The lacustrine soft soil thickness,miscellaneous fill thickness,elastic modulus ratio,slope in the cross section and slope in longitudinal direction of the road five factors are regard as the main factors of the deformation of slope lacustrine soft soil foundation,through the orthogonal test,sensitivity analyses of three cases including longitudinal differential settlement,settlement and lateral displacement cross the section are carried out.