March 21, 2024 Kehl, Germany 

At the beginning of March, the good news came from the Trans Europa Naturgas Pipeline (TENP) project: the breakthrough for a pipeline underpass near Kehl, close to the quarry pond in the district of Kork. There, the construction company Sonntag built a 331-meter-long tunnel with an internal diameter of 1.40 meters to pass under the B28 main road and the Kinzig river. This tunnel serves as a protective pipe for laying the pipeline and made it possible to fully maintain traffic on this busy section of the B28. Thanks to the use of trenchless tunnelling technology, the road did not have to be torn up and the course of the Kinzig remained untouched. 

The pipe jacking was carried out by a so-called AVN machine from Herrenknecht. This type of machine has already been in use for decades for numerous infrastructure projects for the construction of supply and disposal lines in a wide variety of geologies worldwide. Unlike the large-diameter machines used for the Brenner Base Tunnel, for example, the pipe jacking method does not involve assembling tunnel rings from concrete segments behind the tunnel boring machine, but rather pushing prefabricated concrete pipes forward through the ground from the launch shaft. The existing geology is excavated with a drill head, mixed with drilling fluid and transported to the surface via the machine using pumps.

The project met with great interest from the local population. Groups of visitors came to the construction site several times during the course of the project. The drilling work went smoothly and lasted around two weeks.

MACHINE/PROJECT DATA M-1938M

• Machine type: AVN1200
• Diameter: 1.720 mm
• Cutterhead drive power: 132 kW
• Tunnel length: 331 m
• Geology: gravel, sand
• Client: SONNTAG Baugesellschaft mbH & Co. KG
• Project owner: Trans Europe Nature Gas Pipeline, Open Grid Europe