Investigation into some design aspects of ballasted railway track foundations using numerical modelling

Abstract

Railways have become the most popular means of public transportation in many countries around the world. Therefore, an investigation into the impact of design parameters affecting the overall behaviour of railway track foundations under train dynamic loading is necessary for optimum and reliable design. Railway track foundations consist of a graded layer of granular media of ballast and subballast, which is laid on a naturally deposited subgrade soil. Most available methods for design of ballasted railway track foundations assume linear elastic behaviour for track geomaterials. However, the resilient behaviour of track geomaterials, especially the ballast layer, is mostly non-linear and may incur plasticity, depending on the level of applied stress. In this paper, a sophisticated three-dimensional finite element modelling is developed to investigate the track response subjected to train moving loads, by considering actual characteristics of track geomaterials including non-linearity and plasticity. The results are compared with the simpler elastic modelling response, and the practical implications are discussed.