Non-coincident contact deformation behavior between double-block ballastless track interlayers under normal load

Abstract

Interlayer damage presents a substantial challenge in ballastless tracks, impacting their operational performance. In order to assess the contact deformation at the interfaces between concrete layers, normal loading tests were conducted on the non-coincident contact between rough interlayer surfaces of a double-block ballastless track. A contact model was developed that considers elastic, elastoplastic, and plastic deformations. The study established the relationship between normal load and contact area, and derived a formula to calculate normal deformation stiffness. The results indicate that: I) the model effectively simulates normal contact deformation behavior between layers; II) during loading, the normal load increases non-linearly with displacement, while minimal elastic recovery deformation is observed during unloading; III) the composite rough interface morphology is the most crucial parameter influencing contact deformation behavior; IV) the relationship between normal load and contact area is linear. Additionally, the normal deformation stiffness is positively correlated with the nominal contact area, contact area stiffness, and the value of the rough interface point cloud height distribution function at the corresponding deformation. The presented elastoplastic contact model and deformation stiffness calculation method contribute to understanding the operational performance of ballastless tracks following interlayer cracking.