The threshold of 10 km of the Lyon-Turin base tunnel was reached at the end of September. At Saint-Martin-la-Porte, after the Federica TBM had completed the first 9 km of the tunnel through which trains will travel, the excavation of a further one and a half kilometres using conventional method has reached one kilometre. In this stretch of the mountain, which is particularly difficult from a geological point of view, two fronts are advancing with caution using hydraulic hammers and, where possible, explosives. These fronts are then consolidated with fibreglass and self-drilling anchor bolts. About 500 metres of the planned 1,500 metres still have to be excavated using this method.
At the same time, work is proceeding on the other construction sites: at La Praz the dismantling of the Federica TBM is at its final stage, while at Saint-Jean-de-Maurienne the construction site for the temporary station is operational, since the existing railway lines will be connected to the new base tunnel. At Saint-Julien-Montdenis, work is progressing on the cut-and-cover tunnel, the artificial tunnel that will constitute the French entrance to the base tunnel, while on the other side of the River Arc, at Villargondran, consolidation of the embankments is proceeding to raise the land in the area where construction of the new line in the Saint-Jean-de-Maurienne plain will subsequently start.
In Italy, the Chiomonte construction site is ready for the construction of the niches for the interchange of vehicles within the La Maddalena exploratory tunnel, which will facilitate the transit of construction site vehicles. The grouping of companies completed the niche executive project before the summer and we are waiting for the Ministry’s approval to start the work. The Maddalena tunnel, created for exploratory purposes, will be subsequently used as a service and ventilation shaft for the base tunnel. At the same time, Sitaf is currently carrying out tender procedures for the construction of the new Chiomonte junction on the A32 motorway, to avoid interfering with local traffic, and for the transfer of the Susa truck terminal to San Didero.
