The contract includes the design and construction, through an EPC, of twin tunnels with an internal diameter of 8.75 m, performed with 4 tunnelling machines, each measuring 18 km long.
Once completed, the twin tunnels – designed for high-speed trains reaching up to 250km/h – will link the cities of Oslo and Ski and will be the longest railway tunnels in Scandinavia.
This is the second and largest of the four EPC (turnkey) contracts included in the Follo Line project, the largest infrastructure project in Norway so far.
The works performed with the tunnelling machines start in the middle of the route, where the facilities serving the keystones and concrete plants are located. Access to this area, where a rescue area and two caverns for the assembly of the tunnelling machines have been installed, is carried out through a series of tunnels built by digging and blasting. The tunnel’s lining is composed of around 20,300 prefabricated rings, with seven keystones each, measuring 40 cm thick.
ACCIONA in JV with Ghella has been working hard to mobilise the Follo Line Rail project since its award in March 2015. The four TBMs are now on site and are currently being assembled to commence tunnel boring. These specially designed TBMs will have an average excavation speed of 12-15 m/day.