Finite element analysis on properties evolution of slab track FLC under the coupling action of rainfall and fatigue load

Abstract

The filling layer concrete (FLC) is the crucial component materials in the CRTS III slab track structure. In order to investigate the properties evolution of FLC under the coupling action of environment and fatigue load, a three-dimensional finite element model of the CRTS III slab track structure system was established, and extended finite element method (XFEM) was used to calculate the stress intensity factor (SIF) of the crack tip under different conditions through the domain interaction. Results show the fatigue load significantly decreases stiffness of FLC. Coupling actions of water-saturated and fatigue load, acid-rain and fatigue load accelerate the deterioration of FLC. The decrease of stiffness leads to stress redistribution in FLC. With the increase of fatigue load, the stress of FLC decreases, but the stress of steel in the FLC increases. Positions of fatigue load on FLC take on significant influence on the evolution of properties. The deterioration rate of FLC at the end of the slab is greater than that of the middle FLC. Under the coupling of fatigue load and environment, FLC at the end of the slab is more likely to crack and propagation, and the cracks are most likely to appear from the bottom of the FLC. Due to the influence of the stress field and displacement field at the crack tip, with the fatigue load increasing, the SIF at the external crack of FLC has an exponential decrease. The coupling action of environment and fatigue load accelerates the deterioration of FLC, and also leads to the rapid reduction of SIF. In this study, the coupling of acid-rain and fatigue reduces the properties of FLC most obviously.