By rosebell
As 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, the Brenner Base Tunnel (BBT) project company announced that TBM Ida is due to meet a fault zone in the H41 Sill Gorge-Pfons, the northernmost construction site of the BBT project.
Including two main tubes and an exploratory tunnel, connecting tunnels, side tunnels, emergency stops, as well as four lateral access tunnels, BBT is a complex tunnel system.
Already 5km of tunnels has been completed by the two TBMs Lilia and Ida, which are working through the mountains in the H41 Sill Gorge-Pfons construction.
Achieving impressive results in the last one and a half years, these TBMs are currently less than 3km away from their destination in the municipal area of Navis and both of them have already interrupted two disturbance zones, Viggartal and Walzn.
While the TBM Ida in a few days 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.
In order to safely carrying out the necessary securing work, TBMs must reduce their speed when driving through the fault zone.
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.
According to H41 Sill Gorge-Pfons construction site lot controller Ivan Zamberlan: “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.”
