Construction of the ventilation shafts and 22 km of the base tunnel crossing the border
Major works are currently underway on the base tunnel:
- The ventilation shafts: four parallel vertical tunnels at an altitude of 1,300 metres, connecting the underground station of Modane located 500 metres below. They will ensure ventilation and safety of the tunnel.
- Technical caverns: seven caverns (up to 22 metres high and 23 metres wide) that will be used for the assembly of the TBMs that will excavate towards Italy
- Other underground work: the Modane underground safety site, as well as the 22 km of the base tunnel between the Villarodin/Bourget-Modane access adit and the Italian border.
Pictures of the construction site
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The companies at work (CO5a)
TELT awarded the contract for the construction of the Avrieux shafts to a consortium comprising VINCI Construction Grands Projets, DODIN CAMPENON BERNARD, CAMPENON BERNARD Centre Est, WeBuild, and MASTER DRILLING Europe. The Egis / Alpina consortium is responsible for project management and supervision.
The companies at work (CO5)
TELT a attribué le contrat pour la réalisation du chantier opérationnel CO5 au groupement composé d’Eiffage Génie Civil, SPIE Batignolles Génie Civil, Ghella et Cogeis. TELT awarded the contract for the construction of the CO5 operational site to the consortium composed of Eiffage Génie Civil, SPIE Batignolles Génie Civil, Ghella and Cogeis.
Techniques and works
The four parallel shafts with a diameter of 5.2 metres are excavated using Raise Boring Machines, a technology developed in the mining industry specifically for the mechanised excavation of vertical shafts of small diameter. Once the pilot holes are completed, the excavated material, which falls by gravity in the chamber at the base of the shafts, is taken out through the existing access adit.
The Villarodin-Bourget / Modane 4,036-metre-long access adit, excavated from 2002 to 2007, will play a crucial role for the ventilation, the maintenance and the safety of the base tunnel. This construction site has also enabled the testing of the transformation of inert excavation materials for concrete aggregate.
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