Abstract：Considering the interpenetration phenomena between ballast layer and subgrade surface, the soil resistance using hyperbolic function is applied to ballast located at interlayer. Based on proposed transfer algorithm of contact force between discrete sphere and hexahedron element, a coupled discrete-finite element model of ballasted railway track is established considering interlayer creation. The ballast granule with irregular shapes is constructed using the clump model in DEM. Meanwhile, the subgrade is modeled using 20-node hexahedron solid elements in FEM. The effect of the traffic load and the subgrade stiffness on the overall settlement of the ballast bed was analyzed. The stress and displacement contours in the cross section of model are drawn. It is found that the proposed coupling model can not only present the elastic and cumulative plastic deformation of the ballast layer itself, but also reflect the penetration settlement caused by the penetration of the ballast into the soft subgrade surface. The study can provide an important insight for understanding the settlement and degradation mechanism of ballasted rail track under high speeds and heavy loads.
2021, Vol. 42 
