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ABSTRACT
It is well-known that as the train speed exceeds a threshold value track deflections increase considerably leading to the need for frequent maintenance and the possibility of train derailment in the worst cases. This threshold speed is usually assumed to be proportional to the Rayleigh wave velocity of the softest underlying soil layer. In the present research, three dimensional multi-layer finite element analyses are conducted for different train speeds. Energy absorbing boundaries are used to avoid any possible fictitious ground wave reflections. Ballasted railway tracks laid on soils with different levels of stiffness are studied. By considering both linear and non-linear soil behavior, the relationship between soil stiffness and railway track response is presented which is used for defining track speed limits and any track improvement/maintenance requirements. The track response compared to experimental observation reveals the capability of the proposed model to predict railway track behavior for different ground conditions and speed levels.
Proceedings of 9th International Conference on Railway Engineering, London June 2007