Half of the tunnel in the Oslo direction has now been excavated.
Some 50% of the concrete tunnel lining rings have been manufactured.
The ACCIONA Ghella Joint Venture (AGJV) consortium, of which ACCIONA Construction is a member, has reached an important milestone in the Follo Line project after reaching the halfway point in the tunnel being bored towards Oslo.
The two tunnel boring machines (“Queen Eufemia” and “Queen Ellisiv”), which are excavating from Åsland to Oslo, have already drilled 4.5 kilometres of tunnel since they began work in September and October last year, respectively. This represents half of this section of tunnel and is significantly ahead of the planned schedule. Another two tunnel boring machines (“Anna fra Kloppa” and “Magda Flåtestad”) began drilling from the same point, but towards Ski, at the end of last year.
A pioneering method in Norway is being used to construct this 20 km dual railway tunnel, in which four tunnel boring machines (TBMs) are being used simultaneously in conjunction with traditional drilling and blasting methods.
The TBMs have been especially designed for the hard Norwegian rock and are operating as planned in terms of technology, quality and propulsion. Each machine is 150 metres long, weighs 2,400 tons, and will drill a ten-metre diameter tunnel for a distance of nine kilometres, which is then simultaneously lined with concrete segmental rings.
Some 50% of these rings have been manufactured to date. Specifically, a total of 10,005 rings (consisting of 80,040 pieces) have been manufactured by the production lines at the three factories in Åsland that are producing these prefabricated sections.
Each tunnel lining ring consists of six components in order to create a hermetic tunnel, with an additional element required to ensure a uniform surface and enable the reinforced track to be installed. Production of the 20,010 rings to be installed will conclude next year.
The AGJV consortium is on schedule with the planned project calendar, ensuring parts are manufactured to the highest quality and safety at every stage. A total of 201 people are working on the production team at the prefabricated plants, producing an average of 290 ieces (for 36 rings) every day.
“The AGJV has reached an important milestone in the project, ahead of schedule. We are extremely pleased with the work carried out and with the progress made to date. The key to success is having teams with extensive international experience and excellent work planning”, said project manager, Fernando Vara.
The Follo Line is the largest transport project carried out in Norway to date. It is part of the wider inter-city development plan for south-east Oslo, which seeks to improve and promote the country’s transport infrastructure. It includes construction of 22 km of railway line between Oslo and the new train station in Ski and is scheduled for completion in December 2021.