Major milestone reached on world’s longest immersed tunnel


Major milestone reached on world’s longest immersed tunnel

Ground investigation work for the €7.1bn (£6bn) Fehmarnbelt Tunnel between Denmark and Germany has been completed, according to contractor Fugro.

The 18km immersed tube tunnel, which will be the longest in the world when complete, will link the two countries by road and rail and will significantly reduce travel time compared with the current ferry service. The project gained the final approval from the German government in November last year and work has already started on site.

Fugro delivered the ground investigation for Femern Link Contractors which will build the new tunnel link. Femern Link Contractors is a consortium formed by Vinci Construction Grands Projets, Per Aarsleff, Wayss & Freytag, Max Bögl Stiftung, CFE, Soletanche Bachy, Bam Infra and Bam International, with Cowi providing consultancy services.

According to Fugro strategic sales and marketing manager Michael Neuhaus, the knowledge gained by the ground investigation work will “to improve cost and time management during the preconstruction and design phases”.

The recent work delivered by Fugro included geotechnical site characterisation of the sub-seabed soil at both tunnel entrances, as well as investigation of the Rødbyhavn site on the Danish side where the precast tunnel elements will be manufactured. Fugro deployed its Skate 3 jack-up platform, a custom-designed geotechnical spread, and a specialist data acquisition team to perform core drilling and downhole cone penetration tests.

While final design work is still underway, construction of the breakwaters at the tunnel portals has started and work has started on the harbour for the tunnel element casting, which will manufacture the 79 tunnel elements and 10 special elements for the scheme. Work on the German side of the tunnel is expected to commence in the middle of this year and the tunnel is expected to be completed in 2029.