aThis paper is concerned with the problem of ground vibrations induced by railway traffic and its modelling. An important modelling aspect is without doubt the track/soil interaction, which can play an important role in the generation of seismic waves. To avoid excessive computational resources, a coupled lumped mass model (CLM model) of the soil has been developed and is considered in this study. From Lysmer's analogue model, an extension is proposed considering the coupling between foundations, according to their contact area and distance. The mass/spring/damper systems for the foundation are interconnected by other spring and damper elements. The model parameters are carefully determined by matching the soil direct and indirect impedances with the ones obtained from a finite/infinite element model. The influence of ballast and soil stiffnsses are presented, in order to determine the range of validity of the CLM model. Combined with a discrete 2-layer model of the track, it offers the possibility to work with a simple compound track/soil model. Illustrative examples are discussed, considering the track receptances calculation with possible soil heterogeneities or the rail deflection under a moving vehicle. Focusing on typical results based on the tram of Brussels, the effect of track/soil coupling is investigated, showing that a significant difference can be observed depending on whether coupling is introduced or not.
|Title of host publication||19th International Congress on Sound and Vibration 2012, ICSV 2012|
|Number of pages||8|
|Publication status||Published - 1 Jan 2012|