ABSTRACT
Lot H41 Sill Gorge-Pfons is one of the largest construction lots of the Brenner Base Tunnel, continuing the construction work in Austria from the Sill Gorge (Sillschlucht) to Pfons, building on the construction work already carried out in the previous E41 Sill Gorge and H33 Tulfes-Pfons lots. Construction lot H41 Sill Gorge-Pfons was started in January 2022 and is scheduled to be completed in 80 months. With this construction lot, a total of approximately 22.5 km of main tunnel tubes, 38 cross-passages and the remaining Innsbruck emergency stop will be driven using both drill and blast methods and TBMs.
The findings from the approximately 16.5 km long exploratory tunnel, which was driven between September 2015 and July 2020 with an open gripper TBM in combination with anchor bolt and shotcrete ground support measures, were taken into account in planning the mechanized excavation of the main tunnel tubes, each just over 8 km long, with single-shield TBMs. The mechanized tunnelling of the main tunnel tubes with single-shield TBMs in combination with a predominantly single-shell sealed segmental lining is now well advanced. Several fault zones have been driven through that had already been excavated with the exploratory tunnel. This paper presents the experience gained to date from the mechanized excavation of the main tunnel tubes with single-shield TBMs, as a comparison to the findings from the mechanized excavation of the exploratory tunnel with an open gripper TBM.
