Albulatunnel II - New Construction
|Company||PORR SUISSE AG in consortium|
|Principal||Räthische Bahn AG (RhB)|
|Location||Preda-Spinas - Switzerland|
|Runtime||04.2015 - 12.2022|
A new tunnel to the Engadine.
The Albula tunnel runs through the heart of the Swiss mountains, connecting the municipality of Preda in the Albula Valley to Spinas in the Engadine. The decision was made to build a new tunnel more than 100 years after the existing tunnel was opened. Once Albula Tunnel II has been completed, the existing tunnel will be repaired and converted into a safety tunnel. All work on the new, single-track railway tunnel will be carried out while maintaining railway operations.
The centre distance to the old tunnel is 30m. The two tunnels will be connected via twelve cross passages. The total length of the new Albula Tunnel II is around 5,860m and the excavated cross-sections measure 35 to 46m2 – up to 60m2 in the rauwacke (gypsum-bearing dolomite) regions. The main tunnelling operations are carried out simultaneously from both the Preda and Spinas portals, and will be undertaken for the most part using full-face excavation and blasting methods.
A 110m long section (approximately 1,000m behind the Preda portal) runs through the rauwacke, where complex geological and hydro-geological conditions necessitate the highest degree of structural expertise. Materials management and logistics constitute one of the major challenges in the Albula Tunnel II railway construction project.
Logistics and materials management are among the greatest challenges of this prestigious project in the middle of the Swiss mountains.© PORR
Drainage mats and waterproofing foil are laid between the concreted inner and outer shells.© PORR
Twelve cross passages connect the new tube with the existing Albula Tunnel I. To ensure frost resistance, Tunnel II is protected from ingress of mountain water by an umbrella seal at locations with high water intake.© PORR
The concreting of the bottom and the drainage pipes required to discharge the mountain water took place in a very constricted space.© PORR