Lifetime Performance Assessment of Railway Ballastless Track Systems Affected by a Mortar Interface Defect

Abstract

Defects at the interface between the slab track and the cement asphalt (CA) mortar layer can have significant effects on the dynamic response of a vehicle-track system. This paper proposes a method for analyzing the reliability of the ballastless track system affected by a CA mortar gap during service life. A vehicle-track vertical coupling dynamic model considering a CA mortar gap was proposed, and the response surface model representing the dynamic response of the vehicle-track system was obtained. Sensitivity analysis was then undertaken to evaluate the key parameters of the CA mortar gap for the long-term performance of a ballastless track system. The two most critical failure modes were identified and used to construct the corresponding limit-state equations for reliability analysis. The results from numerical studies show that the CA mortar gap has significant influence on the key dynamic responses and can significantly affect the long-term service performance of ballastless track.