Providing a fast railway link between northern and southern Europe through Switzerland, the Gotthard Base Tunnel will form the core of the new transalpine railway axis, AlpTransit.
It will consist of twin single track high speed rail tunnels running 57 km between Erstfeld and Bodio. The maximum overburden is over 2 300 m. Pöyry' services in this major project include environmental services, tunnelling, electromechanics, rail traffic and ventilation/safety.
The southern three design lots of the Gotthard Base Tunnel cover the most technically challenging sections of the alignment. This southern section of the tunnel includes the intermediate adits at Sedrun (800 m vertical shaft) and Faido (2 700 m inclined gallery) and the multifunction stations where these adits meet the base tunnel.
The Sedrun lot will be excavated by conventional means, the Faido and Bodio lots by open TBM's. The lining consists of shotcrete rock support with an inner lining of cast in-situ concrete.
The southern part of the tunnel runs to the north predominantly in gneiss and granite of the Gotthard massive, and to the south in the Pennine gneiss zone. These relatively straightforward zones are intersected by the Tavetsch Inter-mediate Massif, Urseren Garvera zone and the Piora syncline, all of which are particularly demanding with soft rocks under high pressure.