Modelling the Critical Speed Amplification Effect on Railway Track-Ground Systems

Abstract

The railway track vibration generated by the train passage depends upon the individual and combined effect of its various components: the train, the track and the supporting soil. In the case of the train, higher speeds result in larger vibrations on the railway structure. Moreover, amplification occurs when approaching the so-called ‘critical speed’, and the response is further increased when considering the multiple axles effect. Regarding the track, the type and properties also influence the overall structure response, increasing the wheel-rail interaction forces and magnifying the vibrations. Similarly, the supporting ground features directly affect track behaviour, propagating the total railway system response and causing disturbances in nearby structures and increasing the localisation of energy at transition zones. Although different numerical approaches meant to study these amplifications effects have been developed, deep-wave propagating problems induced by high-speed trains require more elaborated simulations. Thus, this paper investigates the railway track amplifications due to speed, focusing on the different track types and soil layering effects, for which semi-analytical approaches simulating the track-ground dynamic complex behaviour are employed.