Modeling of railway track integrating a shock-absorbing mat at the sleepers-ballast interface using eigenfunctions of displacement.

Damage caused to railway tracks and the surrounding environment during trains passage have become a real concern for those involved in the railway sector over the years. To find a solution for this problem, several approaches have already been implemented on railway tracks in some countries. Despite the efforts made in this area, the problem of ground vibration induced by railway traffic still remains a concern. Therefore, many studies have been focused on solutions to attenuate, even cancel vibrations effects on the track and nearby environment. This work has presented a modeling of a ballasted railway track with a shock-absorbing mat or Under Sleepers Rubber Mat (USRm) at the sleepers/ ballast interface. Using the equation of wave propagation in the ground and the constitutive law, the eigenfunctions of the displacement vector were determined. By coupling the equations of the track and those of the ground, the displacement, the velocity, and the acceleration of each track component, as well as the stress on the ground surface were expressed. The Newmark numerical method was used to represent these variables and to highlight the (USRm) influence on the dynamic behavior of the different track component. Comparison of the results obtained with the proposed railway model shows a reduction in vibration amplitudes of 64.9% and 94%for the rail, 86.5% and 56.25% for the sleepers. At the ground surface, the attenuation of vibration is evaluated at 53% and 6.85%, respectively for linear and nonlinear cases. The insertion of the shock-absorbing mat (USRm) in the railway track structure also reduces stress at the ground surface. The configuration of the railway track with a damping mat (USRm) therefore significantly reduces the transmitted vibration to the ground and to the nearby structures. It also contributes to the stability of the track and the improvement of its performance. The proposed railway track model with a shock-absorbing mat can be considered as a solution to reduce vibrations generated on track and the ground during trains passages.