Force Characteristics of Longitudinally Coupled Slab Track Turnout on Bridges under Temperature Action

Abstract

With a longitudinally coupled slab track turnout on LeiDa Bridge on the Wuhan–Guangzhou passenger dedicated line in China as an example, an integral finite element model of a turnout (crossover)–slab track–bridge–pier was developed. This model considered two No. 18 welded turnouts with movable frogs in the form of crossover, longitudinally coupled slab track, bridges, and piers as one system. The computational results included the temperature force and the displacement regularity of the turnouts, slab track, bridges, and piers. Their effect parameters, such as the extensional stiffness of the track slab, the friction coefficient of the sliding layer, and the setting of the anchor point, were also investigated. The key findings are that (a) the additional longitudinal forces and the displacement of rails induced by temperature changes increased with reduced slab extensional stiffness, whereas the corresponding forces of the turnout components decreased significantly; (b) the longitudinal distortions of the track structure were insensitive to the failure of the sliding layer but posed negative impacts on the forces and anchor points of the piers; and (c) it was necessary to arrange anchor points on large-span bridges to prevent rail displacement and reduce the negative effects of forces on the piers.