Coupled Discrete-finite Element Method for Settlement Analysis of Transition Zone between Ballasted and Ballastless Track with Polyurethane Reinforcement Based on Computer Aided Technology

Abstract

This paper presents a coupled discrete-finite element method for the dynamic analysis of the transition zone between a ballasted and ballastless track with polyurethane reinforcement. The discrete element and finite element methods are employed to model the ballast bed and ballastless track slab based on computer aided technology, respectively. Ballast bond models are developed at the particles' contacts to simulate the polyurethane reinforcement of ballasts. A contact algorithm based on static equilibrium is proposed at the interface between the ballasted and ballastless section. To realize a gradual change in stiffness and differential settlement in the transition zone, a multi-level transition is set up from the ballasted to ballastless section by changing the bonding depth. The settlements of different points in the transition zone are obtained and compared. The effect of ballast polyurethane reinforcement is studied.