Effect of Track Speed on the Behavior of Railway Track Ballast System underlain by Clay

Abstract

Railway ballast forms a major component of a conventional rail track and is used to distribute the load to the subgrade, providing a smooth running surface for the train. Currently, high speed (frequency) and heavy haul trains are increasing the loads experienced by the ballast layer. In this paper a full scale railway system is analyzed numerically with finite element method using PLAXS 3D 2013 program. A series of 16 cases simulations for railway track of geometry type (MG) are analyzed. The analysis was performed in order to determine the effects of track speed, clay stiffness and reinforcement on the rail substructure behavior. Eachmodel was analyzed for train speed 30, 60, 90, 120 km/hr., with and without geogrid reinforcement in the ballast layer for comparison. During the simulation, displacements and stresses were evaluated throughout the rail substructure in order to determine the behavior and improvement due to geogrid reinforcement. It was concluded that the improvement in settlement for soft clay model increases by increasing the speed more than 30 km/hr. For unreinforced models with soft clay layer, at low speed (30 km/hr), about 100 % of the total settlement appears in the clay layer. For stiff clay layer model, there is no effect of reinforcement on the behavior of settlement.