In all geologies

A TOUGH JOB
IN THE FJORD

The Follo Line project in Oslo is a technology revolution for tunnel-rich Norway. Previously, tunnels over there have usually been driven with explosives. But for the largest infrastructure project in the land of the fjords, tunnel boring machines are now being used. Since late 2016, four Double Shields from Herrenknecht have been simultaneously drilling through the tough hard rock. A first worldwide and a logistical challenge: in the extremely hard gneiss, the disc cutters wear out faster, requiring up to 4,250 cutter changes per machine in the course of the project. The worn out disc cutters are taken to Schwanau, 1,500 kilometers away, where they are completely refurbished for reuse.

IN NORWAY, TUNNELS HAVE PREVIOUSLY BEEN DRIVEN WITH EXPLOSIVES. NOW WE KNOW THAT TBMS ARE AN ALTERNATIVE, EVEN IN OUR EXTREMELY HARD ROCK.

Anne Kathrine Kalager, Project Manager, Norway‘s state railway company Bane NOR

The close work relation between Herrenknecht and its project partners guarantees optimal cutter management. “We are extremely satisfied with the cooperation of all involved,” says Project Manager Anne Kathrine Kalager. 

Regular maintenance and repair of the machines and their components are the prerequisite for consistently high advance rates in the challenging Norwegian hard rock.

The drives have performed than planned: by March of 2018, 24 of around 37 kilometers of tunnel had already been built. From the end of 2021, high-speed trains will travel through the two new tubes at up to 250 kilometers per hour. The journey time between Oslo and Ski, about 20 kilometers to the south, will be halved from 22 to 11 minutes. For the Norwegian capital with its 600,000 inhabitants and the region around Ski, which expects population growth of 30 percent by 2025, the Follo Line is a lifeline for the new area.

  • Project: Follo Line; Oslo (Norway)
  • Client: Bane NOR
  • Contractor: Acciona-Ghella Joint Venture
  • TBM diameter: 9,900 mm
  • Tunnel length: 2 x 9,500 m, 9,142 m,
    9,128 m