Critical response of a granular railway track under high train velocities

In this paper attention is focused on surface wave propagation in a stratified half space. The half space consists of a granular upper layer that rests on a classic elastic subgrade. The material formulation for the upper layer incorporates an intrinsic length scale, which is the particle size. The intrinsic length scale becomes relevant during high-frequency wave propagation, when the wave length is of the same order of magnitude as the particle size. The dispersion curves that represent the surface wave propagation in the stratified half space will be discussed. It will be shown how these relations can be used for investigation of the resonance behaviour of the structure under a moving, harmonically vibrating load, as is representative for a high-speed train.