An Analysis on the Dynamic Response of a Poroelastic Half Space under the Ballast-Less Slab Track with a High-Speed Load

Considering the bearing characteristics of the ballast-less slab track, a dynamic model of ballast-less slab track - poroelastic half space for the analysis of subgrade vibration is developed. The two sub-systems of the model are coupled by writing the force transmitted from the track to the subgrade as a continuous function using Fourier series representation and satisfying the compatibility condition. And the displacements at the free surface in time domain are obtained by using the Inverse Fast Fourier Transform. Finally the dynamic response of the subgrade is studied by introducing the different track properties in the numerical calculations. It is found that the track vibration will generally decrease with an increasing track base stiffness, at the same time, track vibration decreases rapidly from rail to rail base and the viscous damping of slab bearings plays an important role on controlling the level of track vibrations.