Influences of Subgrade Form and Ground Stiffness on Dynamic Responses of Railway Subgrade under Train Loading: Field Testing Case Study

Abstract To explore the influences of subgrade form and ground stiffness on subgrade dynamic responses under train loading, and thus to optimize the design of railway subgrade, this paper presents field tests of cyclic loading for railway subgrade with different ground stiffness of fill sections and different forms of fill and cut sections. The considered comparisons of dynamic responses included the distribution of dynamic stress in railway subgrade, and the elastic deformation, dynamic stiffness, and cumulative plastic deformation on subgrade surface. Gathered data showed that when fill sections were relatively high (more than 6.0m in this study), the ground stiffness showed insignificant influence on the dynamic responses of railway subgrade. For the comparisons of fill and cut sections, the dynamic stiffness on subgrade surface for a cut section was approximately a half of the one for a fill section, but the cumulative plastic deformation was essentially the same for the fill and cut sections. These results provide references for the optimization design of railway subgrade.