On May 28, students in the Master’s program in Civil Engineering – Structural Engineering visited the Holstein Tunnel, which has been under construction since 2025—a key infrastructure project on Interstate 44 between Kassel and Herleshausen. With a length of approximately 1.65 kilometers, the twin-tube structure passes under the Holstein Mountain between the Sontra-West interchange and the valley bridge Riedmühle.

From excavation to final lining: At the Holstein Tunnel, nearly all construction processes are carried out simultaneously. The students took the opportunity to get a close-up look at these complex construction site logistics. In addition to the simultaneous work inside the tunnel, the tour also focused on the outdoor facilities, where they viewed, among other things, the modern water treatment system and the processing of excavated material (for use as a frost protection material).

As a member of the Geotechnical Engineering Department, Dr. Aselmeyer organized and led the field trip, bringing the complex geology, which poses significant challenges for those involved, to life for the students on site.

The highly varied and interesting excursion concluded with a snack of bratwurst and grilled meat, which provided an opportunity for everyone involved to share their experiences.

We would like to extend our sincere thanks to Mr. Kedzierski of DEGES Deutsche Einheit Fernstraßenplanungs- und -bau GmbH and to Mr. Bucher of BEMO Tunnelling GmbH for organizing the event and for their fascinating presentation of the construction project.

Further information on the new Holstein Tunnel can be found here .