BBT SE says an ecologically sustainable approach was chosen in order to minimise the impact on the environment and on people living in the project area. This includes using aggregates from the tunnel boring in segment production, and opting for rail transport.
The prefabricated reinforced concrete segments for the main tunnel weigh approximately nine tonnes; a keystone around three tonnes; and a base segment 17 tonnes. The segments for the exploration tunnel are around half the weight of those for the main tunnel.
The segments for the H61 Mauls 2-3 lot are manufactured in the Hinterrigger segment plant.
“The aggregates required for the concrete production come from the tunnel boring process,” said operations manager Giorgio Malucelli. “They are mainly transported to Hinterrigger via conveyor belts. The conveyor belts run on the construction site from the tunnel face to the segment plant. After they are completed, the segments are delivered by rail to the TBM, where the tunnel lining is carried out. Each train transports up to two rings, or 16 segments.”
As 30% of the excavated material can be reused for the segments, no material has to be obtained from external quarries, which in turn reduces the number of road transports and the amount of material to be deposited.
In Austria, the Ahrental segment factory is located on the construction site of the H41 Sillschlucht-Pfons lot, removing the need for around 27,000 lorry movements.
For the H53 Pfons-Brenner lot, the production of the segments on the construction site is not possible because of space constraints. However, by transporting the segments by rail, around 40,000 truck movements are avoided. The first segments were delivered to the site last month. TBMs Wilma and Olga begin driving north in September on this section of the tunnel.
