Specificities of Ground Vibration Induced by Freight Traffic, from the Track to a Building

Summary

CSTB, SATEBA and SNCF have started a project called VibsolFret dedicated to the specificity of ground vibrations induced by freight traffic. The first step of this project consists in determining freight specificities in terms of induced ground vibration. A measurement campaign is carried out, on an urban site, near a classic line. Commercial freight and passenger trains run on the track. Measurements are realised in free-field and in a building close to the track.

This measurement campaign allows us to determine some specificities of freight traffic in comparison with passenger train traffic. It particularly shows that global levels are more or less the same between freight rolling stock and passenger rolling stock (with realistic speeds in this case 80km/h for freight versus 120km/h for passenger trains). However, freight traffic induces longer time-signals with very high short-term levels. It is observed for free-field acceleration as well as for the acceleration measured within a building.

Measurements indicate that vibration inside a building is mainly driven by the building structure. To propose vibration reduction solutions by acting on the building itself, a numerical approach is used to simulate induced vibrations with several variations of building structure parameters.

At the same time, a numerical parametric study is carried out to evaluate the impact of mitigation measures installed on the track. This study will allow us to propose the most efficient combination of these parameters in terms of vibration reduction.