DEM analysis of ballast breakage under train loads and its effect on mechanical behaviour of railway track

Abstract

Ballast particles would break down under repeated train loads, which is an important reason for track degradation during the long-term railway operation. This paper develops a three dimensional discrete element model to simulate the mechanical Behaviour of railway ballasted track. The DEM model uses the crushable bonded particles whose geometric shape are generated accurately according to the scanned irregular shape of real ballast samples. Taking the dynamic rail-sleeper force obtained from the vehicle-track coupled dynamics simulation as an excitation, the dynamic behaviour of railway ballast including particle breakage is simulated using the DEM model. For a bonded ballast particle, with the number of its broken bonds increasing, it is broken into fragments under dynamic train loads. The influence of particle breakage on dynamic and deformation behaviour of railway ballast is demonstrated, and the meso mechanical behaviour of ballast is analyzed.