Micromechanical Observation of Ballasted Layer During Tamping Work Using DEM

Abstract In railway tracks, maintenance work called “tamping work” is performed to adjust rail level and to compact ballast layer. However, there is a difference in the gradient of the settlement of ballasted track, a granular layer, after the work. It has been expected that the lifting height of sleeper influence on the settlement after the work, but the relationship between lifting height, compactness and “re-settlement” has not been clarified. Then we simulated the process of tamping work and cyclic loading followed by the work, numerically using discrete elements models to observe deformation of granular layer in micromechanical view. The simulation results showed that the settlement can be reduced by sufficiently decreasing the porosity of the ballast layer even if the lifting height is large. This suggests that additional tamping process is effective to reduce settlement.