Start of Tunnelling Works at South Exploratory Tunnel
On 29 March 2019 tunnelling work for the fourth drilling of Lot H51 Pfons–Brenner began on the south exploratory tunnel, marked by a drilling ceremony. Building the exploratory shaft is a critical milestone in the construction of the largest tunnelling project in the history of Austria. The celebrations were attended by the consortium partners (Porr Bau GmbH, G. Hinteregger & Söhne Baugesellschaft m.b.H., Società Italiana per Condotte d’Acqua S.p.A., Itinera S.p.A), site supervisors and Brenner Basistunnel BBT SE. The construction is scheduled to take around six years, with a contract volume of approximately 1 billion euros.
“The Brenner Base Tunnel is one of the most important infrastructure projects for Austria and the European Union. The construction process is very tight and highly organised in order to successfully meet the contractual construction period of 74 months for the shell construction”, said Porr CEO Karl-Heinz Strauss.
Following intensive preparatory work, the excavation of the approximately 5.6 km exploratory tunnel will be realised with the drill & blast method and secured with shotcrete. Here the geological challenges of the Hochstegen zone will need to be overcome. The shaft will run centrally at a depth of 12 m below the two main tunnel tubes. Around 1.2 km of exploratory shaft has already been driven on the preceding lot “Wolf 2”. The breakthrough in the direction of Italy should occur in around four years. Of the total 60 km of exploratory tunnel of the Brenner Base Tunnel., 38 km have been excavated so far. About 10 km of exploratory tunnel are still to be excavated from Trens (Alto Adige) northwards up to the Brenner.
Largest Construction Phase on the Austrian Side
Work on Lot H51 Pfons-Brenner began in late autumn 2018. The construction phase for the Brenner Base Tunnel involves building two main tunnel tubes between Pfons and Brenner, around 9 km of exploratory tunnel, and the emergency stop and transfer point at St. Jodok. The two main, single-track tunnel tubes will primarily be driven with tunnel boring machines (TBMs). This means that a stretch of up to 30 m can be driven per day and per TBM. The entire lot is supplied via a single access shaft.
TBM Flavia is on its Way
On April 16, the first of the two large tunnel boring machines that will drive the main tunnel from Italy towards the Brenner Pass was started at the Mules construction site of the Brenner Base Tunnel.
The cutter head of the TBM named Flavia began to turn in the presence of Raffaele Zurlo, Italian CEO of BBT SE, and the heads of the BTC (Brenner Tunnel Construction) consortium, which is carrying out the works, as well as the engineers, technicians and miners whose speciality is TBM excavation.
The machine is 200 m long and weighs 2750 t; it takes 4200 kW to drive it through the depths of the mountain. Flavia will drive the west main tunnel using the experience gained by the excavation of the exploratory tunnel, which was carried out by TBM Serena. Serena began work in May of 2018 and has already driven over 4 km of exploratory tunnel.
While Flavia began her work, the last tunnel boring machine named Virginia was assembled in the neighbouring east main tunnel. Virginia is a twin to Flavia and was scheduled to start work at the end of May.