“We are under the Alps”: at the heart of the Lyon-Turin tunnel construction site, one of the most exceptional in the world

A pharaonic construction site, in the heart of the Alps. Still far from being put into service, thirty years after its launch, the future high-speed rail link between France and Italy will, according to its promoters, make it possible to increase rail freight across the Alps, reduce the number of trucks and pollution caused by road traffic. In total, 164 km of galleries (to the double section of 57.5 km are added service and communication routes) must be dug into the rock. Since 2016, some 38 km have already been dug, including 13.5 km for the base tunnel.

A team from TF1 was able to invite itself into the bowels of this construction site. It is entered through a door dug into the mountainside. “We are in the heart of the mountain with slate, slate terrain. We can say that we are well under the Alps“, says Emmanuel Humbert, director in charge of construction at the Franco-Italian company Tunnel euralpin Lyon-Turin (Telt), in the TF1 news report at the top of this article. When the rock is too hard, it is necessary to The explosive placed at strategic locations on the wall allows for rapid progress. Then, excavators take over.

Worker safety, a priority

24 hours a day, workers take turns on this construction site which never stops. Except for one day, December 4, on the occasion of the Feast of Saint Barbara (new window)patroness of miners, of whom a statue, to watch over them, sits at the entrance to the tunnel. To ensure the safety of workers, a team is responsible for checking on screens that everything is going well. All workers must wear a geolocation badge around their neck.

“It is an access control measure to ensure that people accessing the tunnel are authorized or accompanied. And in terms of safety, we see that there are four people on the odd tunnel and eight people on the even tunnel“, we are told.

A project worth more than 26 billion euros

Supported by the authorities and economic players, the project is contested by environmental activists (new window) who point out its impact on the Alps as well as its constantly increasing cost since its launch. This was estimated at more than 26 billion euros in 2012 by the French Court of Auditors, with no overall figures having been communicated since. The construction of 150 km of tracks on the French side would represent an investment of 10 to 15 billion euros.

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So, to meet deadlines and avoid new costs, there is no other choice than to bring out the heavy artillery. Starting next year, seven new tunnel boring machines will be delivered in spare parts and assembled on site, so as to drill simultaneously in several places on the mountain. Thanks to these tunnel boring machines, the site will progress 10 times faster than with explosives. It should allow the first train to run from 2032, if everything goes as planned.