Influence of Embankment Thickness and Reinforcement on Cumulative Plastic Deformation of Soft Soil Foundation

Abstract:

Soft soil foundation under traffic loading was modelled by implicit dynamic finite element method (FEM).Based on numerical model,calculation and influential factor analysis of cumulative plastic deformation,a study was made of the influence of the thickness of embankment on cumulative plastic deformation induced by traffic loading.Then,from the standpoint of distribution of dynamic deviator stress of soil foundation underneath the center of loading area,an investigation was made into the meaning and mechanism that reinforcement could decrease cumulative plastic deformation of soil foundation.Analysis result shows that the cumulative plastic deformation of soil foundation with about 1 m thickness embankment develops rapidly under traffic loading.The cumulative plastic deformation decreases distinctly with the increasing of the thickness of embankment.As for soft soil foundation which is influenced significantly by traffic loading,geogrid reinforcement can improve vertical stress distribution,and decrease shear stress on the surface of soil foundation.The main reason of the decrease of cumulative plastic deformation of reinforced soil foundation is that reinforcement can diminish deviator stress on the upper part of it induced by traffic loading.

Key words:pavement engineering; cumulative plastic deformation; numerical analysis; soft soil foundation; reinforcement; embankment thickness