Development of a Finite Element Model to Study the Settlement of Ballasted Railway Tracks Subjected to Two Adjacent Moving Trains

Traffic congestions recently increased the demand for adjacent trains with high velocity. However, there is no study on the influence of the interference of two adjacent high-velocity trains on the settlement of railway track. This study, therefore, discusses the development of a robust finite element model to examine this interference using Plaxis 3D. The study involves two distinctive stages to fulfill this aim. The impact of the mesh coarseness, depth of the subgrade layer considered in the simulation, model width, and time step of analysis have been examined in the first stage to ensure independency of the results on those parameters. The second stage involved examining the influence of the inference on the settlement of the railway track. It has been noted that mesh coarseness does not remarkably impact the results in Plaxis 3D. In addition, a model width equal to four times the spacing between the two adjacent trains is enough to eliminate the influence of the width of the finite element model. On the other hand, the time step effect is remarkably affected by the velocity of the trains. Importantly, it has been found that the interference affect the dynamic settlement of the railway track and the critical velocity. The percentage increase of the dynamic settlement ranges between 17 and 58% for spacing between trains of 1 to 10 m.