Dynamic response analysis of piled embankment and train derailment evaluation subjected to seismic and high-speed train loads

Based on a train-rail-piled embankment three-dimensional finite element model, the vibration displacement, acceleration and frequency spectrum of the rail and subgrade caused by combined seismic and high-speed train loads was investigated. On this basis, performance of piled embankment under combined seismic and high-speed train loads was analyzed. Numerical examples indicate that the seismic load dominates the ground displacement and the moving train load has negligible effects on the ground displacement. However, the moving train load has a significant effect on the rail vibration displacement during earthquakes. The rail and subgrade vibration displacement of piled embankment under combined seismic and moving train loads is obviously lower than that of ordinary subgrade, and its dominant frequency tends to transfer from high to middle and low frequency compared with ordinary subgrade, indicating that pile embankment has a good vibration reduction effect. Moreover, the derailment coefficient and lateral displacement of piled embankment is obviously decreased, which provides important guidance that pile embankment has significant vibration reduction effect and thus it can effectively prevent derailment or overturning during earthquakes.