Dredging of the 18 km-long Fehmarnbelt Tunnel trench completed

It was announced on April the 16^th, 2024, that a major milestone was reached for the construction of the world’s longest immersed tube tunnel, the Fehmarnbelt Tunnel, which will connect Denmark to Germany.

Furthermore, this milestone was the completion of dredging work for the underwater trench that the 18 km-long tunnel is going to be placed on.

This trench took the Fehmarn Belt Contractors (FBC) consortium about three years to build, while it was stated that as many as 70 vessels of different types were operating simultaneously at the peak of the work.

The main challenge encountered during this time was the complex geology of the site, which consists of materials ranging from soft clay to hard limestone.

In addition to this, several blocks of very hard granite from the Ice Age were encountered, while one of the largest ones weighed roughly 70 tons and was placed on display at the construction site of Rødbyhavn.

15 million cubic meters of soil were dredged during the trench’s excavation, and were placed behind dikes off the coast of Rødbyhavn, creating 300 hectares of new land.

FBC is now going to focus on removing the temporary dike that was built in front of the Danish tunnel portal, which was placed earlier this year, so that the first tunnel segment can be immersed later in 2024.

Fehmarnbelt Tunnel is going to consist of 89 concrete elements, each measuring as much as 217 meters in length, and weighing up to 73.500 tons.

When completed in 2029, the project is going to slice travel time between Germany and Denmark to 10 minutes by car and 7 minutes by train.