Two Approaches of Finite-Element Modeling of Ballasted Railway Track

Abstract

Use of a ballast is still popular in railway engineering due to its resilience, relatively low noise, and convenience in construction and maintenance. The ballast layer was modeled with two modeling approaches in this study–continuous elastic solid and spring-connected elements. Two-dimensional finite element models were built. The parameters of ballast layers were correlated between two models to assure comparability. Three levels of vehicle moving speed were analyzed with the models. Significant differences of rail deflection and ballast were found in all speed levels. Vibration spectra were also compared to reveal the characteristics of different finite element models. It was found that the model with spring-connected discrete elements had higher characteristic frequency than the simple ballast model. Increasing speed may significantly increase rail deflections and ballast vibration levels and result in particles movements in the ballast layer. A thorough understanding of model characteristics and engineering problems is crucial to choose the most appropriate model.