Static and dynamic response characteristics of a ballastless track structure of a high-speed railway bridge with interlayer debonding under temperature loads

The ballastless track structure of a high-speed railway (HSR) undergoes interlayer debonding during its service due to train loads, environmental loads, and construction. A CRTS Ⅱ ballastless track slab structure is a longitudinally-continuous reinforced concrete structure, and the temperature load is a major factor in the occurrence of interlayer debonding. However, the effect of temperature loads on the static and dynamic response of the CRTS Ⅱ ballastless track structure of an HSR bridge following interlayer debonding is unknown. This study established a finite element simulation model of a ballastless track structure over a bridge and a vertically-coupled dynamic vehicle–track–bridge simulation model. The deformation generated by the track structure at temperature loads was inputted as track irregularity to the dynamic simulation model, and the change laws of the deformation and dynamic response of the track structure under different temperature loads was studied. The results showed that under different temperature loads, the ballastless track slab first undergoes longitudinal deformation, followed by transverse deformation. On this basis, the dynamic response of the HSR ballastless track structure over a bridge with interlayer debonding was found to increase with increasing temperature loads, while the frequency band changed from single to complex. This study not only provides insights into the effects of temperature loads on track structure damage, but also lays a theoretical foundation for the development of maintenance and repair plans for railroad departments.