Balancing technical precision with adaptation to the terrain, this section of the tunnel illustrates the expertise deployed to cross the Alps.
Construction site photos
Key data
0 km
of base tunnel excavated
0 months
of works
0 people
employed at peak activity
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Completion of excavation works
Les entreprises à l'œuvre
TELT a attribué en juillet 2021 un marché de 228 millions d’euros à un groupement composé d’IMPLENIA Suisse (mandataire), IMPLENIA France, NGE, ITINERA et RIZZANI de ECCHER. La maîtrise d’œuvre est assurée par le groupement Egis (mandataire), Ingérop, Alpina et Geodata.
Où en est le chantier ?
Données actualisées en décembre 2025
80%
Completed works
The Saint-Julien-Montdenis covered trench, the future entrance portal of the Mont Cenis base tunnel, was completed in November 2021 after 32 months of works carried out beneath the A43 motorway and the RD1006 road.
In parallel, reinforcement works were carried out on the Arc River embankments in Villargondran in order to protect the Saint-Jean-de-Maurienne basin from flood risks and to prepare the platform for future construction sites. These developments notably made it possible to raise the ground level by nearly 6 metres through the reuse of 25,000 tonnes of excavated material.
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