Work has been completed on a \u201ccomplex and challenging\u201d 5km long section of the Brenner Base Tunnel in Austria \u2013 getting the megaproject one step closer to a cross-border breakthrough.<\/p>\n
The tunnel on construction lot H52 Hochstegen, near the Brenner border, operates through the \u201cHochstegen zone\u201d \u2013 a fault zone characterized by excessively complex geological conditions, which cross from Graub\u00fcnden slate to central gneiss.<\/p>\n
In December 2021, Swietelsky Tunnelbau received the \u20ac102M (\u00a388M) contract for this intricate construction lot. It began work on the lot at the start of 2022.<\/p>\n
Because of the water-bearing presence and carbonate rock layers, the contractor faced considerable challenges with the excavating in this section. In the direction of the Brenner, approximately 900m of exploratory tunnels had to be bored.<\/p>\n
However, the project team encountered a Triassic zone and Hochstegen marble in the exploratory and main tunnel.<\/p>\n
Due to the mentioned intense geological conditions, extensive injections, and safety measures should be carried out over the tunnel\u2019s 23-month construction period to enable safe excavation of the structure.<\/p>\n
A total of 5km of the tunnel has been blasted, of which 3.2km is the main tunnel, 0.9km is the connecting tunnels, and 0.9km is the exploratory tunnels.<\/p>\n
In addition, work on the section has concerned the construction of three branch caverns and two connecting tunnels at the main tunnel level. In total, 400,000m\u00b3 of material has been drilled and blasted, and 4,000m\u00b3 of grout has been injected during the lot\u2019s construction.<\/p>\n
Michael Knapp, the Brenner Base Tunnel (BBT) project manager for the Pfons-Brenner stretch, mentioned: \u201cDespite the technically challenging geology, we got it done within the specified construction time.\u201d<\/p>\n
He added: \u201cThanks go to the responsible construction company and, above all, to the miners who did a great job under these difficult tunnel construction conditions.\u201d<\/p>\n
The lot H52 Hochstegen completion gets the megaproject one step closer to a cross-border breakthrough as the exploration tunnel on the lot is just 2km away from the Italian border.<\/p>\n
Once the tunnel breaks through from Austria into Italy, it is said to link the two countries for the first time \u2013 discovering the ultimate purpose of the project, which intends to connect Italy with Austria through a 64km long railway tunnel.<\/p>\n