On Saturday 19 July, production of the precast concrete segments used by the TBMs for the final lining of the line tunnels were completed at the Ahrental plant located  near the Austrian H41 Sill-Pfons Gorge construction site. The plant, which began operating in February 2023, produced approximately 90 segments per day, for a total of 59,066 segments weighing 10 tonnes each. 

There was no railway connection in the Ahrental construction site area for transporting materials from outside. For this reason, the ARGE H41 temporary consortium chose to produce the segments directly on site. Production took place in series thanks to an innovative plant, which made it possible to organise the work in several stages: formwork, reinforcement, concrete casting and hardening. An internal transport system ensured continuity in processing, optimising time and resources and ensuring high quality standards. After storage, the segments were transported inside the mountain to a depth of 1,000 m, first by a special vehicle and then by a construction train, to be finally laid by the TBMs. Each of the 8,438 lining rings installed consists of six segments plus a base segment.

If the concrete elements had been produced outside, transport to the construction site would have required approximately 29,500 truck trips. By opting for an efficient and sustainable solution, the number of trips was reduced to just 3,000, which were only necessary for the supply of construction materials and reinforcing steel.

The Ida and Lilia TBMs are advancing towards their goal

While the production of segments at the H41 construction site is coming to an end, excavation work continues on the same lot with the two TBMs, Ida and Lilia, advancing southwards towards the neighbouring H53 Pfons-Brennero construction lot, simultaneously laying the prefabricated segments for the tunnel lining. Both operational since summer 2023, Ida and Lilia cover a total distance of just under 17 km. Currently, Ida and Lilia are approximately 400 m and 800 m respectively from their destination in Navis.

Project progress

To date, 200 km of the 230 km of tunnels planned for the Brenner Base Tunnel project have already been excavated: 93 km (train tunnels), 57 km (exploratory tunnel) and 50 km (other tunnels). 

For further information on the project click here, at/16 and it/103 for the tunnelbuilder archive and also visit https://www.bbt-se.com. 30/25.