Webuild Uses Liquid Nitrogen to Freeze Underpass Section of Tunnel
Webuild has started using a special application to allow workers to excavate a tunnel under the Isarco River safely and sustainably without having to divert the natural course of the river. The Group is overseeing the use of liquid nitrogen to freeze the ground along the second of four tunnels being excavated for the underpass, the most important task at the southernmost end of the Brenner Base Tunnel project. The first tunnel was completed in December 2020. When including the ring around Innsbruck that leads to Munich, the Brenner will be the longest railway tunnel in the world at 64 kilometres. Once completed, it will be an exemplary piece of infrastructure for sustainable mobility in Europe, creating an axis between Verona and Munich.
Webuild is the leader of the joint-venture with Strabag AG, Strabag S.p.A., Collini Lavori S.p.A. and Consorzio Integra responsible for the construction of these four tunnels that will serve two railways for a high-speed/high-capacity train service and two other railways that will connect with the existing railway. By freezing the ground, workers can proceed with the excavation of the second tunnel without being hindered by water infiltration.
For the excavation of the first gallery, they used 3.4 million litres of liquid nitrogen delivered by trucks from facilities in northern Italy and Australia. The rate of delivery was one an hour for seven days. Once the freezing is complete, the excavation work will proceed along with the strengthening of the walls for about 50 metres.