Analysis of Railway Ballast Settlement with Discrete Element Method

Abstract:

Based on a model of convex polyhedron ballast, a method for evaluation of the particle size is proposed under the condition of minimal shadow area of it. By contrast with the evaluation methods of particle volume and minimum bounding square perpendicular to the principal axis of minimum moment of inertia, a detailed analysis of the abovementioned method is carried out. Then the particle size of ballast particle is evaluated through using it. By establishing the accumulation masse of ballast particles with single and broad particle size distribution, the influence of different particle size distributions on the ballast settlement is analyzed. The results show that the proposed evaluation method in this paper provides a more accurate evaluation for the particle size of ballast particle. When the initial packing density of ballast is 1.55 g?m-3, the value of accumulated settlement of sleeper with broad particle size distribution is less than the one with single particle size distribution. And the value of accumulated settlement of sleeper with a large particle size is greater than the one with a small particle size.

Key words:ballast settlement; discrete element method; particle size distribution; particle size evaluation