Fully-coupled numerical model for ballasted track analysis – Field measurements and predictions

Abstract

This paper proposes a three-dimensional fully-coupled numerical model intended for the simulation of the dynamic behavior of ballasted railway tracks under real excitation. It is employed to reproduce the response of a French site located at the high-speed line connecting the two regions Bretagne and Pays de la Loire. The equation of motion is solved in the time domain by means of the finite difference method in which the rails and sleepers are represented by rectilinear beam elements which are rigidly attached to a spatial grid composed of rectangular cuboids. An adaptive meshing scheme based on the creation of load-attached moving nodes is adopted to model the moving train loads which are supposed to be time-independent. To validate the numerical simulations, a measuring campaign is performed in which tow aligned deflectometers are used to measure the displacement of the railway foundation just below the ballast layer under the track centerline. The velocity range of the high-speed passenger trains is covered in which four cases are taken into consideration ranging from 162 to 342 km/h. An excellent agreement between measurements and predictions is found. Therefore, the presented model can be considered reliable for the design of new high-speed lines.