Germany, Dornum
Uninterrupted record

Dornum in Germany's East Friesia region is the final destination of a gas pipeline coming from Norway. The coastal strip is primarily characterised by the tidelands which are a conservation area. A tunnel, 98 percent of whose total length of 2.6 kilometers runs beneath the tidelands, was planned to protect the nature reserve and safely lay the pipeline. 

Reinforced concrete pipes with a diameter of three meters were driven through the tidelands by the AVN3000AH, whose special feature, a cone crusher, broke up the excavated material so that it could be removed with the slurry conveyance. The machine was steered from the control container in the target shaft via a light wave conductor cable. The tunnel itself was only entered for monitoring or maintenance. With an average advance of 26 meters per day, it was possible to reduce the projected construction time by a good two months. Until today, the record of a drive of 2.5 kilometers without intermediate shafts has not been challenged.

Data Sheet

Country, Location

Germany, Dornum






Soft ground
Turf, clay, marl, sand

Tunnelling length

2,535 m

Machine Data

1x AVN Machine:
Diameter: 3,820 mm
Lining method: Pipe jacking
Cutterhead power: 264 kW
Torque: 1,800 kNm

Your contact person Contact us

Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.