ACCIONA Ghella JV Completes Half of Norway’s Follo Line Tunnel

By TBM News November 14, 2017

The first of the four TBMs for the Follo Line project during factory acceptance. Photo: Herrenknecht.

The ACCIONA Ghella Joint Venture (AGJV), which includes ACCIONA Construction and ACCIONA Engineering, has now completed 50% of the tunneling for construction of the high-speed tunnel between Oslo and Ski for the Follo Line project.

A total of 18 km (half of the total) have been drilled since the first tunnel boring machine began operating in September 2016. This milestone was reached significantly ahead of the initially planned timeline.

A pioneering method in Norway has been used to construct the twin rail tunnels, comprising four tunnel boring machines (TBMs) working simultaneously, combined with traditional excavation and blasting.

The “Queen Eufemia” TBM, the first to begin excavation work, has already drilled 5.3 km, while the “Queen Ellisiv”, which began operating one month later, has advanced a similar distance, just 150 m behind. Both machines are working from Åsland toward Oslo and are expected to reach the Norwegian capital in summer 2018.

The other two machines (“Anna fra Kloppa” and “Magda Flåtestad”) began tunneling from the same point but toward Ski late last year, and have now drilled 3.8 km (42%) and 3.6 km (40%), respectively.

Specially designed for the hardness of the Norwegian rock, the TBMs are working as expected in terms of technology, quality and propulsion. They are 150 m long and weigh 2,400 tonnes. Each one will drill nine km of tunnel, 10 m in diameter, which will be simultaneously lined with segmented concrete rings.

The project also includes the design, construction and installation of the rail system, once the tunneling work has been completed.

“We are extremely pleased with the work done and the progress made to date. We have a highly qualified team and the project is moving forward according to plan thanks to their efforts and excellent collaboration with Bane NOR. Our goal is to meet the established deadlines and budgets, and this milestone shows that we are moving in the right direction,” said project manager Fernando Vara.

The Follo Line is the largest transport initiative ever undertaken in Norway. It is part of the interurban development plan for southeastern Oslo, which aims to improve and promote the country’s transport infrastructure. It includes construction of 22 km of rail line between Oslo and the new train station in Ski and is scheduled for completion by December 2021.