Service performance of CRTS II ballastless track in high temperature tunnel

Abstract

Considering the dynamic balance of heat conduction between tunnel floor and track structure, heat convection and heat radiation between track surface and air, a finite element model for the temperature field of CRTS Ⅱ ballastless track in the high temperature tunnel is proposed and the dynamic responses of the vehicle-track coupling system are studied. Firstly, the influences of the temperature of the tunnel floor on the temperature distribution and warpage of the track are investigated. Secondly, the dynamic responses of the VTCS excited by the additional irregularity of the track induced by the temperature of the tunnel floor are investigated, and the effects of track deformation on dynamic characteristics at different speeds are compared. The findings demonstrate a linear relationship between the maximum and minimum temperatures of the upper and lower surfaces of the track slab and the temperature of the tunnel floor. In comparison to rail, the maximum displacement of the slab is larger, and the warpage deformation with symmetrical distribution of the track slab is characterized by concave in the middle and arching on both sides. The fastener stiffness has no effect on the deformation of the slab, but the vertical displacement of rail increasess as the fastener stiffness enlarge. Temperature load enlarges the excitation of the wheel-rail system so that intensifies the dynamic response. The faster of the speed of vehicle is, the effect of additional track irregularity on the dynamic response is the more pronounced. The research reveals the mechanism of high temperature tunnel on the service state of track, which supplies a theoretical basis for the design and maintenance of track.