Dynamic Responses Law of Subgrade of a Special Railway Line in Loess Region

In order to investigate the dynamic response law of subgrade of a special railway line in loess region under moving train loading, the field test data and 2.5D finite element results were adopted to assess the dynamic stress distribution and its influence depth, and the environmental vibration law in the office area along the line was also analyzed. The results show that the excessive abstraction of the track system might enlarge the amplitude and influence the range of dynamic stress. The entity modeling of the 'ballast-sleeper-fastener' system makes the distribution of the dynamic stress in the subgrade more reasonable. The influence of energy consumption caused by the dynamic creep of soil have a negligible influence when the subgrade is in a quasi-static state. The speed has a negligible effect on the distribution of the dynamic stress of the subgrade when a freight train is running at a low speed, and the influence depth of the dynamic stress is about 4.2 m. As the speed decreases, the influence of track