SBB, Railway line CEVA, Geneva
From the end of 2019 onwards, the CEVA rail link will connect Geneva's main station with the Eaux-Vives station in the south of the city and Annemasse in France.
Plans for this ambitious project date back as far as the 19th century. It calls for the construction of a new twin-track 8.8 km section that will mostly run underground, and it also involves refurbishing and upgrading 7.3 km of existing track. The construction work poses exceptional challenges because the route passes through densely built-up urban areas with numerous buildings that are prone to subsidence as well as highly compressible subsoil layers in some cases.
The project comprises five railway stations – four of which are underground – as well as two conventional tunnels, several cut-and-cover tunnels and one bridge.
The underground stations and the open-cut tunnels have mostly been constructed using the cut-and-cover method, whereas the shotcrete technique was used for the conventional tunnels. Depending on geological conditions, they were executed partially by means of full-face excavation with face stabilization and partially with sequential excavation. Various auxiliary construction measures (e.g. pipe umbrella) made it possible to underpass many sensitive old buildings without causing any damage.
Services provided by Gruner Ltd Geotechnical Engineering Department comprise:
- Mandate as inspection engineers for the five railway stations, the cut-and-cover tunnels and the two conventional tunnels (phase: plans for public display and execution).
- Verification of project basis and hydrogeology, examination of the construction process and static calculations.
- Development of comparative calculations, e.g. for various subsidence and deformation forecasts for the supporting structure, the subsoil and the existing structures (3D finite element method (FEM).
Geotechnical engineering and foundation