How the tunnel under the Fehmarnbelt will be built

The Fehmarnbelt tunnel will be five times as long as the link under Øresund and therefore the longest of its type in the world. The Fehmarnbelt tunnel will be an immersed tunnel comprising a railway and motorway. It will be built using the same tried and tested principles as were used for the Øresund tunnel.  At the same time, technologies and methods have been refined and adapted for the Fehmarnbelt link based on the international experience gained in the area since the Øresund fixed link was completed in 2000. 

Efficient construction method 

The immersed tunnel will comprise 89 elements made of reinforced concrete at a factory in Rødbyhavn. There are two types of tunnel elements: 79 standard elements and 10 special elements. The special elements will have a special ’basement’ for machinery, which will make the construction process and maintenance of the finished tunnel easier. The tunnel elements will be manufactured using industrial batch production, which will streamline the process considerably. 

Secure positioning on the seabed

The finished element will be sealed with a large bulkhead to enable it to float and then pushed into a specially designed basin near the factory.  From here, the element will be towed out to the Fehmarnbelt and placed into position. Here, the element will be carefully lowered into a dredged trench on the seabed.  The first element on each side of the belt will be connected to the portal facility which will connect the coast and sea. The new elements will then be linked together until the tunnel can be assembled with a special element in the middle of the Fehmarnbelt. The elements will be covered with gravel, sand and stone as they are linked together. The top layer of stone will be more or less level with the existing seabed.

In short, the immersed tunnel will securely sited below the sea bed, protected against ships’ anchors and collisions.