The Brenner Base Tunnel (BBT) project company announced that TBM Ida will meet a fault zone in the H41 Sill Gorge-Pfons, the northernmost construction site of the BBT project.
BBT SE is a public limited company formed to build the 55km railway tunnel between Innsbruck in Austria and Fortezza in Italy and is equally owned by the two countries.
BBT is a complex tunnel system consisting of two main tubes and an exploratory tunnel, connecting tunnels, side tunnels, emergency stops, and four lateral access tunnels.
The two TBMs Lilia and Ida, which are working through the mountains in the H41 Sill Gorge-Pfons construction, have driven 5km of tunnels in 2024.
They achieved impressive results in the last one and a half years and are currently less than 3km away from their destination in the municipal area of Navis.
Both TBMs have already interrupted two disturbance zones, Viggartal and Walzn.
In a few days, the TBM Ida will face a new disturbance zone, dubbed Werner, which is located under the doctor’s salon in the community of Pfons.
TBM Lilia is also expected to encounter a similar disturbance section in the main tunnel east, in about a month.
When driving through the fault zone, TBMs must reduce their speed to safely carry out the necessary securing work.
The concrete inner shell is being continued on the already broken-out tunnels, and about a quarter of the planned inner shell is already completed in the main tunnel tubes to the north.
H41 Sill Gorge-Pfons construction site lot controller Ivan Zamberlan said: “Due to the findings gained during the exploration tunnel, an area with strongly rugged and unstable rock was identified.
“In order to ensure safe tunnelling, we will reduce the speed of the tunnel boring machine and carry out securing work in the next few days.”
