Finite Element Modelling of Geogrids Reinforced Ballasted Tracks

AbstractThis paper presents results obtained from three-dimension finite element modelling (FEM) to study the effects of geogrids on the deformation responses of ballasted tracks. In this study, a series of numerical simulations are carried out on track sections with and without the inclusion of geogrids. Sensitivity analysis was carried on parameters affecting the performance of geogrid, including the axial stiffness, interface property and the location of geogrid placement in the track substructure. The tracks are subjected to moving train loading under 150 kN wheel load travelling at a given speed of 72 km/h. Based on simulation results, it is found that geogrid provides a reinforcing function to rail track primarily in the form of confinement which resulted in reduced lateral displacement in a reinforced track compared to a traditional track. A significant reduction in vertical and lateral displacement is found from the inclusion of a geogrid layer at the ballast and capping interface while the effect of geogrid reinforcement is more pronounced with increased loading cycles. The effects of geogrid stiffness, interface conditions and geogrid placement are studied and it is found that the axial stiffness of geogrid is found to impact overall track deformation while the optimum placement of geogrid is found to directly at the ballast and capping interface.