Study on physical model of the crossing of the Rhône flood plain by a new railway line near Lyon

Abstract

In order to address the questions raised by a new railway line crossing the Rhône, and in addition to mathematical modelling conducted during the preliminary studies, SNCF Réseau commissioned Artelia Eau & Environnement with a physical scale model study of the projected infrastructure. The physical scale model represented the river Rhône and its flood plain, the existing bridges over the river Rhône for the A432 motorway and the high speed line, and then the project (viaduct and relief structures). After calibration of the measurements devices, tests were carried out in current conditions, in design conditions and in optimised design conditions. The physical scale model enabled to identify the hydraulic impact of the project during flood events (increase of the maximum water level, due to bad flow conditions at the inlet of relief structures) and validate the improvements of the design (reshaping of the relief structures' inlet, and removal of embankments close to the relief structures). The final optimized design ensures the hydraulic transparency of the project.