Non-uniform variation characteristics of temperature field and corresponding thermal effect of longitudinal continuous slab ballastless track structure

The longitudinal continuous slab ballastless track structure (LCSBTS) easily suffers from interface and joint damage when subjected to extremely high-temperature loads, significantly affecting the running smoothness and safety of high-speed trains. This paper establishes a numerical model of the LCSBTS using the heat transfer principle and real-time shadow technology to replicate the time-varying evolution and spatial distribution of the temperature field. The corresponding thermal effect is obtained based on the sequential thermal-mechanical coupling method. The results show that the temperature variation and the corresponding thermal effect exhibit strong temporal-spatial non-uniformity on the horizontal and vertical planes of the LCSBTS. Solar radiation and heat convection are the dominant factors for the temperature field of the LCSBTS in the daytime and night, respectively, resulting in a higher temperature and greater thermal deformation on the sunny side than on the shady one. The temperature and vertical thermal deformation along the longitudinal direction vary periodically with a specific wavelength between the two adjacent rail support concrete blocks. The thermal deformation increments under the studied nonuniform temperature loads cause an interface damage increment. Finally, the consideration of a non-uniform temperature load produces remarkably different thermal effects from those given by the design temperature load.