Brenner base tunnel, construction lot H41 Sill Gorge–Pfons: challenges based on previous construction lots in the project area

The construction lot H41 Sill Gorge–Pfons is one of the biggest construction lots of the Brenner base tunnel and carries out the work on the Austrian side between Austria and Italy. It is situated between the Sill Gorge in Innsbruck and the small mountain village of Pfons. Here, tunnel excavation and inner lining concrete works are carried out based on existing caverns and tunnels made by previous construction lots E41, Sill Gorge and H33 Tulfes–Pfons. The construction lot H41 Sill Gorge–Pfons started in January 2022 with preparation works, and will take 80 months of continuous construction work to complete. All together about 22.5 km of main tubes, 38 bypasses and the remaining parts of the underground Innsbruck emergency station/stop will be excavated by the drill and blast method and by mechanised means (TBM). Additionally, concrete inner lining works will be executed partly alongside the excavation works. In the connection tunnels which are already finished and link the existing Innsbruck bypass with the new Brenner base tunnel, barrier walls are being erected and a new long‐distance water flushing system is being implemented. The limited surface areas in this mountainous region present a huge challenge for logistics and storage as well as on‐site operations for the execution of this complex underground construction lot.