Sedrun tunnel, lot 360, AlpTransit, Gotthard Base Tunnel

Short description

Construction of two parallel single-track railway tunnels using blasting, and construction of a multi-function station.

The project

  • Context: The Gotthard Base Tunnel (GBT; German: Gotthard-Basistunnel, Italian: Galleria di base del San Gottardo, Romansh: Tunnel da basa dal Son Gottard) is a railway tunnel through the Alps in Switzerland. It opened on 1 June 2016, and full service began on 11 December 2016. With a route length of 57.09 km (35.5 mi), it is the world's longest railway and deepest traffic tunnel and the first flat, low-level route through the Alps.
  • Railway tunnel with two single-track tunnel tubes, each approx. 9.0 km long, excavation cross-sections 60–134 m2 (full excavation), cross-passages every 312 m.
  • Multi-function station (MFS) with longitudinal and transverse caverns, four tunnel changeover expansions (excavation cross-section up to 230 m2), tunnel changeover connections, side tunnels, ventilation tunnels and 14 ventilation shafts, 4 maintenance halls.
  • Access via tunnel, length approx. 1 km, and two shafts with a depth of approx. 800 m. Challenge: highly complex installations.

Services in detail

  • Blasting, securing with shotcrete, anchors, netting.
  • Special heading in squeezing rock zones (northern part of the Tavetsch intermediate massif), securing with deformable steel structures, anchors, shotcrete, solid stabilisation of the working face.
  • In-situ concrete tunnel lining.
  • Shaft II: raise drill with subsequent expansion using shaft boring machine (diameter 7 m).

Challenges

  • Clavaniev zone (CZ), Tavetsch intermediate massif (TZM)
  • Urseren Garvera zone (UGZ), Gotthard massif

Further information

  • Special heading under tough geological conditions (squeezing rock, radial convergences of up to 70 cm). 
  • Challenging logistics: Supplying the construction site via an approx. 1000-metre-long access tunnel and two approx. 800-metre-deep blind shafts.
  • Reusing and processing the excavated material for producing the concrete (in-situ concrete approx. 328,500 m3 and shotcrete approx. 222,500 m3).
  • Total excavation volume 3,700,000 m3, total weight of arch structures approx. 20,000 tonnes of steel.