Breakthrough has been made on another internal diaphragm on Lot H53 Pfons-Brenner of the Brenner Base Tunnel (BBT).
The internal diaphragm in the west main tunnel was demolished last week, about 1,200m below the Padauner Kogel. The excavation was carried out by drill and blast.
This breakthrough was made less than a month after the H53 BBT consortium of Porr and Marti broke through the diaphragm wall in the east line tunnel.
These latest milestones mean 85% of excavations for the entire BBT project have been completed. Last month mechanical excavation on the Italian side was completed when TBM Flavia, the last of three TBMs operated by the Webuild-led consortium for the H61 Mauls section, finished excavation of the west main tunnel.
H53 Pfons-Brenner was the last of the BBT tunnelling works to be awarded and is the largest construction lot on the Austrian side of the project.
It includes two TBM drives of 7.6km each; 10km of tunnel using the NTAM method; 1.6km of exploratory tunnel; and 37 cross-passages with a total length of around 2.6km.
The two 10.37m-diameter Herrenknecht TBMs – Wilma and Olga – were launched in September last year.
