Influence of Under Sleepers Rubber Mat on Propagation of Vibrations from a Railway Track Lying on a Semi-Infinite Soft Ground

Abstract

The damages caused on railway track and on surrounding ground by trains motion’s vibration are since many years a worry for track engineers. In the view to mitigate those negative effects, several proposals and solutions have been implemented in the track. This paper presents significant improvement in track performance resulting from the use of Under Sleepers Rubber mat (USRm) in a ballasted railway track subjected to a dynamic vertical load. Taking into account previous studies on the use of resilient materials under the track component to mitigate railway borne-vibrations and well-advanced studies on the behaviors of rubbery materials: viscoelastic, hyper elastic and those of railways vibratory, settlement, we have analyzed the influence of the Rubber mat inserted between the sleepers and the ballast on the amplitudes of the vibrations generated on the track and the ground by the moving load. By the use of Fourier transform and Gauss-Tchebychev algorithms, vertical displacements in the track and on the ground surface are determined. Results from the study indicate a substantial decrease in vibration amplitudes on the ground surface as much as 20% or 50% respectively at 5 Hz and 40 Hz. Indeed, USRm provides additional protection for the ballast layer by softening wave’s propagation. The new insights will help track engineers to make appropriate decision on the design and usage of USRm.