Enlargement of the 160-year-old Fachingen tunnel in Germany has been completed.
On November 21, the tunnelling system, named Nora, broke through the crucial wall of the tunnel. A consortium of Porr, Feldhaus Bergbau and Heinz Schnorpfeil Bau used a Herrenknecht Tunnel Enlargement System (TES) to carry out the renewal of the 426m-long tunnel for Deutsche Bahn.
The consortium is also enlarging the 732m-long Cramberg Tunnel. The cross-sections of the two double-track tunnels of the Lahn Valley Railway are being enlarged by 2m.
The TES makes it possible to carry out tunnel renewal during ongoing rail operation. First the existing tracks are dismantled, and a track is laid in the middle of the existing tube. Rail traffic continues to run on the track throughout the construction period as the TES serves as a protective enclosure and separates the construction work from rail traffic.
The mixed geology of clay, slate and keratophyre required blasting to loosen some material. This fell to the side of the TES and was removed by conveyor devices.
After breaking through, TES Nora was removed from the tunnel and concrete was applied to the tunnel interior.
The narrow construction site and the ongoing rail operations created special challenges for the tunnelling team. In addition, the team had to ensure there was no contamination to the catchment area of the Fachinger spring.
