Experimental and numerical investigation of damage development in embedded rail system under longitudinal force

Embedded rail system (ERS) is a new type of track structure with many advantages due to its continuous rail support. The rapid development of urban rail transit all over the world renders its application prospect broad. However, the cracks and debonds in ERS present a threat to the traffic safety and a possibility for high maintenance costs. In this work, a longitudinal pushing experiment was designed to explore the damage development process in ERS in order to help structural optimization and performance maintenance. The first order derivative of displacement-longitudinal force curve indicates that the damage process of ERS could be divided into three stages: linear elasticity, damage initiation and damage acceleration stages. The surface deformation of the elastic poured compound (EPC) was analyzed with the particle velocimetry and it is shown that the damage is possibly localized in a small EPC part. Statistics of the absolute displacements of a large number of interrogation areas show that their percentage distribution changes in agreement with the increment of rail displacement, which could be the basis for monitoring of EPC deformation in the breathing zone of continuous welded rail. The analysis of the deformation of EPC from side views, together with the qualitative analysis with finite element method, reveals that the large shear strain of rubber strip and the intense shear strain of EPC at rail foot are the main causes of damage initiation and growth in ERS under longitudinal force.