Influences of Under-Track Foundation Diseases on Track System

In order to study the influence of the under-track foundation disease on the track system, based on the CRTS II slab ballastless track in ABAQUS, this paper analyzes the influence of the overall temperature, temperature gradient, CA mortar layer stiffness and voiding, and fastener system stiffness changes on the track system. The results show that the tensile stress of the track slab, the vertical displacement of the rail and the track slab and the vertical compressive stress of the mortar layer are all linearly related to the change of the temperature field, and increase with the increase of the temperature load. The stiffness of the fastener mainly affects the deformation of the rail. The damage of the CA mortar layer deteriorates the service performance of the track structure. The stiffness of the CA mortar layer has a great influence on the transverse tensile stress of the track slab. Both the length and width of the void have adverse effects on the rail, track slab and mortar layer. And when the void width reaches 1.5 m, the transverse tensile stress of the track slab reaches the maximum value, while the impact of the void height on the track system is relatively small. The outcomes provide a quantitative basis for establishing scientific maintenance thresholds and optimizing repair strategies, essential for ensuring the long-term serviceability of high-speed railway infrastructure.