Temperature-induced deformation of CRTS II slab track and its effect on track dynamical properties

Two finite-element models of the CRTS II slab track are presented to simulate temperature-induced deformations of the concrete track slab with no deterioration or with a deteriorated cement asphalt mortar (CAM). One model, which considers the fully bonding interface between the slab and the CAM layer, could applied to a track that is in good condition; the other model uses cohesive zone elements to simulate the deteriorated CAM with some possible interfacial separation and slip. Utilizing both of the models, temperature-induced warp deformations of track under various temperature loads are investigated. The influence of temperature deformation on the dynamic properties of the track is analyzed based on the train-track coupled dynamics. Numerical results show that the deteriorated CAM layer can significantly increase temperature deformations of a CRTS II track slab, which would produce tiny rail irregularities. There are clear differences between the deformation shapes of the track slabs that have an inseparable mortar layer and those have a separable mortar layer. The track slab with a deteriorated mortar layer showed more open curl distortion than the track slab in good condition. The dynamical response index of the slab track is intensified to a certain level due to the temperature deformation; with an increase of the train speed, the track dynamical responses increased linearly. However, rail irregularities due to the temperature deformations are very tiny. Even if a track is exposed to extreme temperature loads and the mortar layer is deteriorated, temperature deformation can have a negligible effect on the track's dynamical properties.