Dynamic Performance of Pile-Supported Bridge-Embankment Transition Zones Under High-Speed Train Moving Loads

Faster degradation of railway tracks can be observed in bridge-embankment transition zones. Degradation is triggered by abrupt variation in the track's vertical stiffness due to different support conditions. Developing efficient transition zone design strategies is imperative to minimize this problem. For slab track-embankment over soft soil areas, very limited consideration has been given to ground improvement when designing transition zones. In this study, cement fly-ash gravel piles were used to improve the soft ground near a bridge and two pile configurations were considered. The dynamic performance of the slab track-embankment-ground system under high-speed train moving loads was investigated using a finite/infinite-element simulation approach. The dynamic responses of the slab track-embankment-ground system change more smoothly near the bridge abutment in the case of varying-length piles, and are amplified in the vicinity of the bridge abutment when a train travels from the embankment to the bridge.