Accumulative Damage of the Interface between CRTS II Track Slab and CA Mortar Layer under Cyclic Temperature Loads

摘要

A finite element model of the CRTS II slab ballastless track is built to calculate its structural stress and bulking deformation under the cyclic low-high temperature loads. In this model, the cohesive zone model with the bilinear traction-separation constitute relation is used to simulate damage behaviors of the interface between track slab and CA mortar layer. Then, the maximum negative and positive temperature gradient load is set to -22.5 °C/m and 45 °C/m according Chinese climate features and the previous researches. Finally, accumulative damage of the perfect interface and the degraded interface are analyzed respectively. For the perfect interface with desired adhesive strength, the damage area appears at the corners and edges of the interface, and it does not expand distinctly with the increase of load cycles. For the degraded interface with weak adhesive strength, the damage area expands rapidly from the border edges to the center of the interface. The debonding area percentage reaches to 98.6% after 20 load cycles. The cyclic temperature loads are fatal to the degraded interface between the track slab and the CA mortar layer, and it is extremely important to maintain the desired interface adhesive strength for the CRTS II slab ballast track.