Dynamic characteristics of the sleeper-ballast bed under heavy haul railway train load

To analyze more accurately the dynamic response of sleeper and ballast bed under heavy haul railway train load, this paper uses parallel bonded spherical elements to simulate concrete sleeper structure, which can realistically simulate the load transfer from sleeper to load, and rigid clusters with realistic shape to simulate ballast particles. The reliability of the model is tested by verifying the vertical stiffness and lateral resistance and comparing them with the experimental data. The train load is applied to the area on the sleeper in contact with the rail to study the settlement and vibration response of the sleeper and the ballast bed. The results show that the vertical displacement of the sleeper is different at each place under the train load, the displacement of the sleeper in the area under the rail is significantly larger than the shoulder and the center of the sleeper, and the bending deformation of the sleeper is W-shaped; the displacement and vibration amplitude of the sleeper will increase when the train speed increases; the internal stress of the sleeper under the rail is much larger than the center of the sleeper, the influence degree of sleeper center will increase with the increase in train speed. The ballast particle displacement and vibration will decrease with the increase in the ballast bed depth, and the ballast displacement and velocity in the area below the rail action is larger than that in the ballast shoulder and bed center area.