TELT has awarded the contract to build the Avrieux ventilation shafts to the consortium comprising VINCI Construction Grands Projets, consortium leader, Dodin Campenon Bernard, VINCI Construction France, Webuild and Bergteamet. The construction work is worth around € 220 million, will last for 36 months and employ up to 250 people including workers and managers.
The contract concerns the construction of four vertical shafts to be excavated from the foot of the Villarodin-Bourget / Modane access tunnel. The shafts will be 500 meters deep and have a diameter of 5.2 meters. They will be excavated using Raise Boring Machine type TBMs, a technology developed by the mining industry for vertical excavation of small-diameter tunnels. This technique is especially efficient in terms of worker safety and minimises the impact on the territory since it requires a smaller working area above ground. Excavated materials will be removed from the shaft through the existing access tunnel. The contract also includes construction work at the foot of the access tunnel required for proper operation of the shafts, in particular the excavation of 7 caverns up to 22 meters high and 23 meters wide that will subsequently be used to assemble the TBMs to excavate the base tunnel towards Italy.