Damage deformation of ballastless track and its influence on dynamic response of vehicle-track in seasonal frozen area

In order to discuss the influence of damage and deformation of ballastless track on driving safety and track service performance in seasonal frozen regions, the typical ballastless track structure in seasonal frozen regions of China was taken as the research object. Based on the finite element method and concrete plastic damage constitutive theory, a refined nonlinear analysis model of CRTS III slab ballastless track with considering structural reinforcement was established. The deformation and damage characteristics of track structure under subgrade frost heave were studied. Based on the multibody dynamics method, a dynamic model of the high-speed vehicle-track-subgrade coupled system was established. The dynamic response of the vehicle-track-subgrade coupled system under frost heave deformation of the subgrade was analyzed. The results are drawn as follows. The frost heave position can significantly affect the deformation and development of damage in the track structure and the generation and development of interlayer seam. When frost heave occurs at the middle position of the base plate groove, the interlayer seam value is the largest. When frost heave occurs at the position of the base plate groove, the rail displacement is the largest. When frost heave occurs at the position of the expansion joint of the base plate, macroscopic cracks appear earliest on the base plate. The deformation and damage and interlayer seam value of the track structure increase with the increasing frost heave amplitude, and the decreasing frost heave wavelength. The base plate is more prone to damage compared to other track structures, so it is recommended that the frost heave amount that produces cracks on the bottom of the base plate can be taken as a control criterion. Differential frost heave of the subgrade can intensify the dynamic wheel-rail interaction, which can have adverse effects on driving safety and track service performance. The vertical dynamic response of the wheel-rail interaction on high-speed railways increases with the rising of frost heave amplitude of the subgrade. The frost heave deformation and the increase of its amplitude below 20 m frost heave wavelength have a particularly serious effect on the dynamic response of the track, which should be paid more attention to. The results can provide a theoretical basis and engineering guidance for the dynamic performance evolution and service safety of the basic structural sections of high-speed railways in seasonal frozen regions. © 2024, Central South University Press. All rights reserved.