The Kerenzerberg Tunnel is part of the A3 national road and is located on the cantonal territory of Glarus between the Weesen and Murg junctions along the Walensee.

  • 5250 Meter long safety tunnel
  • 107 Million CHF
In 1986, the approximately 5,700-meter-long Kerenzerberg Tunnel was opened to traffic and needs to be upgraded in terms of safety technology as a result of the guidelines and standards that apply today. On behalf of the Swiss Federal Roads Office (FEDRO), the KER450 consortium is constructing the core of this overall upgrade - the construction of a new safety tunnel (SiSto) parallel to the existing tunnel, which will simultaneously serve as an escape route and an exhaust air duct.

The SiSto will be excavated over a length of 5,250m with a hard rock double shield TBM (ΓΈ 7.10m) and lined with steel fiber segments. As later escape routes, cross-connections (18 pieces) will be excavated every 300m and exhaust tunnels (52 pieces) to the existing road tunnel will be excavated every 100m by blasting to extract the exhaust air. To accommodate the electromechanical equipment for the operational equipment, sub-centers will be built at the portals and at each of the quarter points of the SiSto.

Special feature: The excavation of the cross-connections and the exhaust tunnels will be carried out in parallel with the TBM driving. To make this possible, new types of autonomously drivable, electrically operated supply vehicles, the so-called ASVs (Automated Service Vehicles), were used.
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