Interaction between Railroad Ballast and Sleeper: A DEM-FEM Approach

Abstract

This study proposed a coupling discrete-element method–finite-element method (DEM-FEM) to investigate the ballast–sleeper interaction under dynamic loading. A surface-coupling algorithm was used to combine the finite-element and discrete-element analyses. A timber sleeper and steel sleeper were selected in the ballast–sleeper interaction analysis. Spherical particles were generated to explore the behaviors of ballast. The porosity of the ballast and the pressure distribution under the sleeper were investigated under the dynamic loading condition. The pressure distribution obtained from the DEM-FEM simulation was compared with the laboratory test. Results showed that the pressure distributions under the timber and steel sleepers were different. Cyclic loading could change the pressure distribution. Validation was performed by comparing experimental results and the numerical results obtained from DEM-FEM modeling. Porosities beneath the steel sleeper were lower than beneath the timber sleeper. For both the timber sleeper and steel sleeper, porosity beneath the rail seat was the lowest, whereas porosity beneath the sleeper end was the largest.