Track-Based Control Measures for Ground Vibration – The Influence of Quasi-Static Loads and Dynamic Excitation

Ground vibration from surface trains is induced by two main excitation mechanisms, due to the moving quasi-static loads and dynamic loads due to track roughness. The relative importance of these two mechanisms has been investigated using a semi-analytical model of the coupled vehicle, track and ground system. The track is represented as an infinite, layered beam resting on one or more elastic soil layers, overlying a three-dimensional half-space of ground material. The train is modelled as a multi-body system with both primary and secondary suspensions and its motion is included. The quasi-static and dynamic loads have been investigated over a wide range of conditions for locations close to the track and further away. Results are shown in terms of insertion gains for both dynamic and quasi-static components for a wide variety of conditions. It is confirmed that an assessment of the effect of a change in support stiffness should not be based on measurements too close to the track – in the case considered the distance should be at least 10 m to give representative results.