High speed railway ground dynamics: a multi-model analysis

High speed railway track and earthwork structures experience varied levels of displacement amplification depending upon train speed. Protecting against amplified track deflections is challenging due to the complexity of deep wave propagation within both the track and supporting soil structures. Therefore it is challenging to derive design guidelines that encompass the full range of influential variables. As a solution, this paper uses a novel multi-model framework where 4 complimentary modelling strategies are combined, and thus able to generate new insights into railway ground dynamics and ‘critical velocity’. The four types of model are: 1) analytical, 2) hybrid analytical-numerical, 3) 2.5D numerical, 4) 3D numerical. They are used to explore subgrade layering, track type, train type, soil non-linearity, shakedown and ground improvement. The findings provide new insights into railway track-ground geodynamics and are useful when considering the design or upgrade of railroad lines