Fatigue characteristics of rubber isolation layers used in high speed railway ballastless tracks: A theoretical and experimental study

Abstract

In order to enhance operational conditions for high-speed trains on long-span bridges, the utilization of rubber under-ballast mats were taken as a novel isolation layer in ballastless tracks. Due to the increased train axle load, it is imperative to conduct investigation into the fatigue properties of the rubber isolation layer, so as to ensure the smoothness of the railways. In this work, a series of fatigue tests were performed on the rubber isolation layer to obtain the influence of stress amplitude and loading cycles on its fatigue performance. The results demonstrate a pronounced non-linear load–displacement relationship of the rubber isolation layer with increasing load, while the fatigue endurance significantly decreases with escalating the stress amplitude. Moreover, considering the hyperelastic properties of rubber material, the Mooney-Rivlin constitutive model was employed in finite element simulations. Subsequently, the stress distributions of the rubber isolation layer were analyzed, and the fatigue life was evaluated based on Luo stress method. The rubber isolation layer exhibits localized damage that does not affect the overall performance after 32 years of normal service condition. Therefore, the fatigue performance of the rubber isolation layer remains reliability, providing assurance for the application in ballastless tracks on high-speed railway long-span bridges.