ROCK TUNNELS | PROJECT
H53 - PFONS TO BRENNER
The remaining large-scale tunnelling works in Austria for the Brenner Base Tunnel are almost totally in the H53 Lot (Pfons to Brenner), which runs to the border with Italy. The H53 contract package was won in early 2023 by a
JV of Porr Bau, Marti and Marti Tunnel, and was the last major package of tunnelling works to be awarded by BBT-SE on the Brenner project. Excavations on the main tubes are well advanced. The Lot only has a relatively short portion (1.6km) of the exploratory tunnel and the tunnelling involved has been completed. The main tunnelling works are taking place mostly
from the Wolf Access Tunnel, with faces being advanced in opposite directions - northwards towards the Pfons area (H41) by TBM, and southwards by Drill and Blast to the border with Italy. The large tunnels for the St Jodok Emergency Stop
are located in the area where the Wolf adit meets the alignment of the Brenner Base Tunnel. Construction works for the Wolf adit and associated
access and logistics tunnels (Padaster, Saxen) were undertaken in 2011- 2015 (Lots E51 & E52), far earlier than the main works which began in 2019. In late 2024, almost a year and a half after award
of the H53 Lot, the two 10.4m-diameter TBMs were launched on their northward drives towards Pfons. The TBMs are ‘Wilma’ (West main tunnel) and ‘Olga’ East main tunnel. Each is to drive 7.6km-long sections of the main tubes, resulting in nearly 15.2km by mechanised excavation. The shields had completed nearly half of their total tunnelling by the end of October 2025. The Drill and Blast works on the main tubes (80m2
)
are to construct almost 10km in total, advancing southwards, towards Brenner Pass. Blasting on the main tubes began early in 2024, before the TBMs were launched on their drives in the opposite direction. Nearly three-quarters of the total blasting for the main tubes has been completed. Final lining works are following.
On the Lot, more than half of excavations for the cross
passages have been completed. Earlier tunnel works in the Pfons to Brenner area
were performed under Lot H51, over 2018-2020, by a JV of Porr, Hinteregger, Condotte and Itinera. That contract was terminated by BBT-SE. With some works completed and looking optimise
the remaining main tunnelling works - and to risk manage dealing with a relatively short but geologically challenging section, at Hochstegen (investigated earlier, during 2016-18, in Lot E53) - the client restructured the package. The challenging section was put into its own Lot, H52, and executed in advance of the balance of remaining main tunnel works, put under H53.
H52 - HOCHSTEGEN As noted, the H52 package involved undertaking works in a geologically challenging area over a relatively short distance, located in the Hochstegen area, close to the Austria-Italy border. The location extends over approx. 500m and the challenging geology involves mainly water-bearing rock layers. Risk management led to this section of Brenner Base Tunnel being handled separately from the balance of work remaining for the Pfons- Brenner package, in which had it had been initially included. The contract was awarded to Swietelsky Tunnelbau
in late 2021 and official ground-breaking took place before mid-2022. The package of works in H52 included, in total: 860m of exploratory tunnel (60m2 (60m2
); 3km of main tunnels - 80m2 ); 600m of connecting tunnels; and, 300m
of cross passages. Significant injection works were performed to improve the rock mass, reduce inflows and the risk of changes to groundwater levels in surrounding protected areas. All tunnelling works in the package were completed
by late 2023.
30 | December 2025
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