• Client: Stockholms läns landsting, Förvaltningen för utbyggd tunnelbana (FUT)
• Main contractor: SBT Sverige AB
• Contractor: Metrostav Norge AS
• Construction period: 08/2020 – 03/2023
• Price: app. 500 000 000 SEK w/o VAT

Project characteristics:

Extension of metro line in Stockholm. The Blue Line is being extended from Akalla to Barkarby – an important travel hub for future public transport passengers, connecting bus services to metro, commuter and regional train services.

Järfälla Municipality is expected to grow to around 115,000 inhabitants by 2030. A new district is emerging around the new station in Barkarbystaden, and the Veddesta industrial area, which is closest to Barkarby station, is also being transformed into an urban environment.

Project data

Chalenges / Specifics of the project

• Complicated and very accurate excavation method along passage under Forbifarten Stockholm tunnels (=2 highway tunnels above our metro tunnels). Difference between bottom of the highway tunnels and the roof of metro tunnels is only 4,9m. That brings very strict limitations and challenges from technological and also controlling point of view.
• Use of rock splitting method to eliminate the fracture zone around the contour along the Forbifarten passage.
• Use of wire sawing method in part of track tunnels and for excavation of one ventilation shafts.
• Breakthrough to existing station without affecting the traffic of the metro.
• Excavation underneath residential area with low overburden which brings strict vibration and noise limits, strict living environment rules and complicated ventilation.
• Complicated geometry and space conditions during excavation of ventilation rooms and big caverns, use of electronical ignition system.
• BIM based project
• CEEQUAL rating and proximity of Natural reserve brings strict environmental rules

Photogallery