Dynamic responses of track system and poroelastic soil under high-speed train load

The vibration of a rail track system on fully saturated poroelastic half-space soil subjected to a moving train load was investigated.The system was divided into two parts,track and ground.The ground was modeled by introducing Biot theory for the fully saturated poroelastic medium.By using the Fourier transformation,the governing equations of the ground were solved.On top of the ground,the ballast was placed,supporting the rails and the sleepers.The rails were modeled as Euler beams,and the sleepers were represented by a mass.The train load was simulated by a series of moving point load in accord with the geometry of a real train.The governing equations of the ground and the rail system were then coupled in the frequency-wave-number domain,and the expressions of displacement and acceleration of the rail and soil as well as the pore water pressure of the ground were calculated.Then their expressions in time domain were evaluated by the inverse Fourier transform computation for a certain load velocities.Computed results showed that the dynamic responses of the soil medium are considerably affected by the fluid phase as well as the load velocity.