Dynamic analysis of high-speed vehicle-track coupled system due to lateral differential deformation induced by subgrade frost heave

Abstract

Subgrade frost heave poses a serious challenge to service safety of high-speed railways in cold regions. Traditional studies often regard subgrade frost heave as uneven deformation along the longitudinal direction. However, this approach is limited as it fails to account for the spatial variability of subgrade frost heave. Specifically, it overlooks lateral differential deformation induced by subgrade frost heave, and neglects its effect on the lateral deformation of the track and dynamic responses of the vehicle. This paper conducts a comprehensive analysis of the mapping relationship between lateral differential deformation of the subgrade and rail deformation, as well as its effects on the dynamic performance of vehicle-track system. Firstly, a refined finite element model of the ballastless track-subgrade system is developed to investigate the correlation between lateral differential deformation of the subgrade and rail deformation. Subsequently, a vehicle-track coupled dynamics model is established to assess the effects of sunny-shady slope ratio, amplitude, and wavelength of lateral frost heave on system dynamic responses. Finally, a control threshold for frost heave is proposed based on the system dynamic responses. The research results indicate that lateral differential deformation induced by subgrade frost heave significantly affects both vertical and lateral dynamic performance, reducing the riding comfort and even threatening driving safety. These findings provide theoretical support for operation and maintenance of ballastless tracks in seasonal frozen soil regions.