“During the course of the contract, we faced difficult geological conditions in several fault zones. It was extremely cold at the beginning of 2024, with temperatures plummeting to minus 30 degrees Celsius. This tested not only our toughness, but also the resilience of our equipment. The tunnel became a frozen cave, the machines froze and every day turned into a thawing struggle for running water. I am all the more appreciative of the fact that we managed everything perfectly and on time,” said Josef Malknecht, project manager at Metrostav Norge.
The Grava fault zone, which made the work on the south portal “more interesting” for the builders, was reinforced with jet grouting, 50 reinforcement frames, 844 anchors and 23.6 tonnes of KARI nets. The completion of the excavations at the northern portal was affected by massive water inflows, which the builders had to spend seven weeks dealing with. The grouting required 660 tonnes of cement and 454 hours of work.
Boring of the Grenland Tunnel began in 2023 and took almost two years. Metrostav Norge did the work as a subcontractor for Eiffage. The main investor in the construction project, worth more than CZK 1 bn, is the company Nye Veier, a Norwegian equivalent of the Czech Highways and Motorways Directorate.
The E18 is an important traffic artery in southern Norway. The 17 km long Langangen–Rugtvedt section near Porsgrunn was one of the most demanding in terms of construction. During the boring of the Grenland Tunnel, the client placed high demands not only on safety and the environment, but above all on the quality of the work.
Metrostav Group has been operating in northern Europe since 2006. Since then, it has completed 15 projects, including Helsinki metro track tunnels, the unique salmon road bridge in Norway and the longest road tunnel in Iceland. It has also carried out tunnelling work in the remote Faeroe Islands. In total, more than 48 kilometres of tunnels have been built in Scandinavia so far.
Radim Mana
Metrostav Group Spokesman
Metrostav a.s. Koželužská 2450/4 180 00 Prague 8
T: 266 019 715, M: 601 110 376
radim.mana@metrostav.cz
