Tverrslag Skøyen, K2C

The Fornebu line is a new metro line which will run from Majorstuen to Fornebu. The track will be built in collaboration with Oslo Municipality and Viken County Municipality. This metro development is the largest in Norway since the large developments of the metro on the eastern edge of Oslo in the 1960s and 70s.

Basic information

  • Client: Oslo Komunne
  • Main contractor: NRC Group AS
  • Contractor: Metrostav Norge AS
  • Construction period: 01/2022 – 08/2022
  • Price: 66 000 000 NOK w/o VAT

Project characteristics

This is part of a project to build a new metro line in Oslo. Fornebubanen will be a new metro line in a connected tunnel system from Majorstuen in Oslo to Fornebu in Bærum. The line will be approximately 8 km long and will have six stations; Fornebu, Flytårnet, Fornebuporten, Lysaker, Vækerø and Skøyen.

Metrostav Norge subcontracted the excavation, securing with bolts and shotcrete and carrying out the grouting in the tunnel.

Tverrslag Skøyen – K2C is a newly bored tunnel with a length of 289 m and a profile of 78 m2 and a niche with a length of 20 m and a profile of 101 m2 , one of several cross tunnels necessary for the main tunnel operation. It is a temporary measure to be „closed“ in the final phase of the Fornebubanen project. It will be used for tunnelling between Skøyen and Vækerø and the station hall in Skøyen The tunnel was driven in shale and limestone in the urban development in the railway protection zone.

Project data

1 piece (289 m + 20 m appendix)
Tunnel:
78 m2 + 101 m2
Tunnel profile:
25 452 m3
Excavated volume:
993 m3
Shotcrete:
375 t Microcement
Grouting:
1 896 pcs
Rockbolts:

Challenges / Specifics of the project

  • Minimum spaces for building facilities, minimum areas for storage of materials
  • Difficult logistic
  • Excavation in railroad protection zone, time limitations
    for blasting, mucking and other noisy activities
  • Excavation provided at a slope of 14,5%
  • Protection of the telecommunications mast at the tunnel
    portal.
  • High tunnel tightness requirements
  • Excavations in inhabited area