Immersed tunnels

The immersed tunnel (or immersed tube) is a tunnel construction method commonly used for crossing a body of shallow water. The method has been widely used for about 100 years, and more than 150 immersed tunnels have been constructed worldwide. They mainly serve as road or rail tunnels, but immersed tunnels are also used for water supply and electric cables. Ramboll provided professional services to a wide range of immersed tunnels worldwide.

Engineers discussing the Fehmarn tunnel


Susanne Kalmar Pedersen

Susanne Kalmar Pedersen

Project Director
T: +45 5161 6243


Ramboll possesses the know-how and experience within all relevant technical fields related to immersed tunnels, for all stages from the early studies and planning to the detailed design. We also assist our clients with construction follow-up, supervision, independent checking and maintenance.

In the capability statement you can read more about the immersed tunnel techniques and services provided by Ramboll. The capability statement can be downloaded at the end of this page.

More information about immersed tunnels


Visit Fehmarn Sund Bælt's website to read more background about the project and see their many videos and visualisations.


Øresundsbron AS is the company for the combined immersed tunnel and bridge crossing between Denmark and Sweden.

Tunnel Engineering brochure

Tunnel Engineering brochure (PDF, 1 MB)

NCE International Tunnelling Award

At the recent International Tunnelling Awards 2013, a team of innovative experts from Ramboll won the “Ground Investigation and Monitoring Award” for the "exceptional geotechnical consultancy work" on the Fehmarn Fixed Link project.

NCE International Tunnelling Award

Immersed tunnels capability statement

Immersed tunnels brochure (PDF, 5.8 MB)


Fehmarnbelt between Denmark and Germany

In the future Scandinavia and the rest of Europe will be connected by the world's longest road and rail tunnel.

Øresund bridge

The Øresund Link

The Øresund Link connects the Danish capital Copenhagen with the city of Malmö in southern Sweden by a four lane motorway and a two track electrified railway for high speed (200 km/h) passenger services as well as freight trains.

Hong Kong

Shatin to Central Link

The North South Line Cross Harbour Tunnel is a 1.7 km immersed tunnel crossing the Victoria harbour in Hong Kong. Ramboll undertakes the role to be the Independent Geotechnical Expert Advice (the ‘expert Reviewer’) for the Immersed tunnel.


Maintenance of the Limfjord Immersed Road Tunnel

Ramboll was chosen to undertake overall repairs on the Limfjorden immersed highway tunnel, which has a total length of 550 meters.


Vlatava River Crossing

The tunnel is part of an extension of the Prague metro system and consist of two tubes app. 6.5 x 6.5 m with a length of approximately 170 m each crossing the river Vlatava. A new technology for immersion, sliding and pulling under water has been invented for this project.

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Tel:+971 4 334 3616
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