Trackbed Mechanical and Physical Characterization using PANDA®/Geoendoscopy Coupling

Most developed countries in the world have large existing railway networks. Most of which are old and have been maintained and partly renewed to mainly upgrade safety, regularity, speed and load. The principal issues of the asset manager are how to prioritize maintenance/renewal works and how to provide engineering teams with reliable geotechnical data for track design on revenue service lines. Indeed, if we can master rail and sleeper specifications, railway natural trackbed remain very variable and difficult to characterize. As a matter of fact, the knowledge of mechanical and physical properties of existing subgrade and sub ballast layers is very important for the future track design. Such data can be acquired through geotechnical tests. However, the majority of classical geotechnical tests can be difficult to carry out on revenue service lines because of existing railway constraints (limited possession times, track access, no destabilization of the track...). Hence, this article presents a new methodology for railway track characterization using light and cost effective tests, based on the coupled use of the PANDA® dynamic penetration tests and geoendoscopy. The goal of this methodology is to provide to the asset manager key point indicator helping with the optimization of the maintenance and renewal strategy.