The final tunnel boring machine (TBM) working on the Italian section of the Brenner Base Tunnel (BBT) has reached its destination, completing excavation of the western main tunnel tube in the H61 Mauls construction lot.
TBM Flavia began tunnelling in April 2019, tasked with excavating 14.3 km from the Mauls site to the Austrian border at the Brenner Pass. Along the way, it installed approximately 65,000 precast concrete segments that form the tunnel lining.
Flavia is the last of three TBMs deployed on the Italian side of the BBT project. Its predecessors, TBM Serena and TBM Virginia, completed the exploratory tunnel and the eastern main tube in November 2021 and March 2023, respectively. Together, the three machines have excavated nearly 43 km of tunnel.
“With the arrival of TBM Flavia, mechanised tunnelling on the Italian side has been successfully completed,” said Gilberto Cardola and Martin Gradnitzer, board members of BBT SE. “This is a result of the dedication and teamwork of the tunnelling crews, planners, engineers, geologists, and all BBT SE staff involved.”
Alessandro Marottoli, BBT Project Manager for the Mauls lot, added: “After Serena and Virginia, Flavia has now also reached her goal, thanks to the determination of everyone involved.”
Flavia faced a major challenge in April 2023 when it stalled approximately 3.5 km from the border due to high rock pressure and fractured geology under 1,200 metres of overburden. Following several technical adjustments and reactivation efforts, the TBM was able to resume progress and complete its journey.
Key specifications of TBM Flavia:
- Diameter of drill head: 10.71 m
- Power: 4,200 kW
- Torque: 27,000 kNm
- Total weight: approx. 2,750 tonnes
- Drill head weight: 260 tonnes
- Total length: approx. 200 m
- Number of transport operations: approx. 170
- Number of components: approx. 80,000
The successful breakthrough marks a major milestone in the BBT, one of Europe’s most significant infrastructure projects, aimed at improving rail connectivity between Italy and Austria under the Alps.
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