Dynamic responses of multilayered poroelastic ground under moving train loads considering effects of track irregularity

This paper aims to explore the dynamic responses of multilayered soft saturated ground underlying rough track subjected to train loads by analytical method. Particular attention has been focused on the roles of the track irregularity. The train is simplified as a multi-rigid-body vibration system and track irregularity results in dynamic wheel-rail loads in addition to the static component due to the vehicle gravity. The track system is modeled by coupling rail, sleeper and ballast, while the soft saturated ground is treated as multilayered poroelastic medium obeying Biot's dynamic theory. The dynamic responses of fully coupled train-track-multilayered poroelastic ground system are analytically solved by Fourier transform, transmission and reflection matrix method, which considers stress and displacement compatibility conditions at the interface between wheel-rail and ballast-ground. Based on the analytical solution, the effects of track irregularity on the additional dynamic load, displacement, acceleration, stress, and pore pressure are discussed. This work has provided practical guidelines for the design of soft saturated ground under the high-speed train.