Immersed tunnel
An immersed tunnel is a tunnel running at the bottom of water , in which the tunnel tube consists of individual tube elements which, like caissons , are manufactured on land, sunk in their target position and then connected.
The tunnel elements, which can be over 100 meters long, are usually made of concrete and steel and are manufactured in a dry dock . The open ends are welded watertight with steel bulkheads . The dock is flooded and the element towed to its destination. Here it is hung on a special ship that acts like a gantry crane . The component is lowered in a controlled manner by slowly filling the ballast tanks in the tunnel element with water. The floating crane is mainly used to secure and hold the position. If the part adjoins the neighboring pipe section precisely, it is first welded from the outside or otherwise sealed before the bulkhead is opened inside.
In submerged tunnels, in order to protect the tunnel tube, it is usually laid in a previously dug trench at the bottom of the water, which is later filled.
Examples of immersed tunnels
- 1961: Rendsburg Canal Tunnel
- 1975: New Elbe Tunnel Hamburg (1st – 3rd tube) along the 7th federal motorway
- 1976: Vlaketunnel along Rijksweg 58 in the province of Zeeland
- 1988: Guldborgsund tunnel as a connection between the Danish islands of Lolland and Falster
- 1990: Crossing under the Frankfurt City Tunnel
- 2000: Drogden tunnel (as part of the Øresund connection between Sweden and Denmark )
- 2003: Warnow tunnel ( Rostock )
- 2009: Marmaray ( Bosporus )
In planning:
- Fehmarnsund tunnel as a connection between Großenbrode and Fehmarn , completion planned for 2028.
- Fehmarnbelt tunnel as a connection between Fehmarn (Germany) and Lolland (Denmark), construction expected to start in 2020
- Weser Tunnel Bremen as part of the A 281 to connect the A1 and A28 with the A27 , construction will start in 2019
Individual evidence
- ↑ Femern A / S: Consolidated Technical Report - Draft. P. 50f, December 2011 ( PDF; 11.8 MB ( memento of January 2, 2016 in the Internet Archive ))
- ↑ Daniel Miller: The greatest projects in the world - Tunnels under the Bosporus . ( Discovery Channel , USA 2007)