Three-dimensional analyses of dynamic responses of track–ground system subjected to a moving train load

The dynamic responses of track–ground system subjected to moving train passages are investigated by the substructure method. The whole system is divided into two separately formulated substructures, the track and the ground. The rail is described by introducing the governing function for an infinitely long Euler beam subjected to the action of moving axle loads of the train and the reactions of the sleeper. Sleepers are represented by a continuous mass and the effect of the ballast is considered. The soil is considered as fully saturated poroelastic medium and governed by Biot’s theory. Using the double Fourier transform, the governing equations of motion are then solved analytically in the frequency-wave-number domain. The expressions of the rail displacement, the rail acceleration, the excess pore water pressure and soil stresses in the time domain are evaluated by the inverse Fourier transform. In particular, the effects of the rail rigidity are studied systematically. Computed results show that dynamic responses of the track–ground system are considerably affected by the rail rigidity as well as the load velocity.