Some Aspects of Support Stiffness Effects on Dynamic Ballasted Railway Tracks

Abstract

The railway track technical literature lacks proper reports on the key effects of the support stiffness on the track behavior with various sleeper geometries. Hence, it is the aim of this research to report on the assessment of the track foundation stiffness. The pyramid model equations are developed for three different stress conditions including WOA model for the cases without stress overlap area in the adjacent sleepers, OAP for considering the stress overlap area between adjacent sleepers with pyramid distribution and OAC for the cases of stress overlap area between adjacent sleepers with cubical stress distribution. A vehicle/track interaction problem studied using the finite element method. The vehicle is considered as a series of moving masses with three degrees of freedom corresponding to the carbody, the bogie and the wheelset masses. The track is considered as beam elements resting on the viscoelastic foundation. The results of the numerical analyses of the vehicle/track system are presented as ratios of the railway track vertical displacement to the vehicle axle load for various foundation stiffness. Many correlation equations are suggested that interconnect the track stiffness with variables such as the ballast depth, the sleeper width, and the sleeper distance.