Abstract:A model of moving traffic vibration loads is developed on the basis of vibration mechanism analysis. Some factors related to vibration such as the speed or bumping motion of the train, the weight of the wheels, and the dispersion effect of the sleeper car are included in this model. A three-dimensional (3D) elastic-plastic finite element model of foundation soil is then established in ANSYS. The Drucker-Prager model is chosen to simulate the soil's non-linear characteristics. The bottom of the model is constrained within the horizontal plane. A 3D viscoelastic artificial boundary is adopted to simulate the bottom of the model and the boundary condition. Under moving traffic loads, the time-history curves of the displacement and the acceleration in various places in the foundation soil are calculated, and several conclusions are drawn. When the load is stationary, the displacement exhibits an abrupt change.However, as the load moves, the displacement maintains a stable value that decreases with distance from the track. When the load is just on, the acceleration also exhibits an abrupt change, with values trending closer to zero as the load moves. Therefore, train speed has little effect on vertical displacement and acceleration.
