The permanent lining of two ventilation shafts at the Mont Cenis base tunnel CO5 worksite in Villarodin-Bourget/Modane has been completed and work is progressing on the third and fourth shafts.
In its latest progress update, TELT, the bi-national company responsible for the Lyon-Turin railway, said the first components of the new TBM to be launched from the site have arrived.
The Herrenknecht gripper TBM has a 10.4m diameter and will be 334m long. It will excavate an 18km section of one of the two Mont Cenis base tunnel tubes, between the Villarodin-Bourget/Modane access adit in France and the Clarea underground safety site in Italy.
At this same worksite, at the base of the access adit, excavation of the safety site galleries has also begun.
A few kilometres away towards Saint-Jean-de-Maurienne, TBM Viviana – excavating the north tube between Saint-Martin-la-Porte and La Praz – has not yet reached its nominal excavation rate because of the massif’s complex geology. The TBM was launched in September last year.
In the same area, excavation work using conventional methods is also continuing from the Saint-Martin-la-Porte and La Praz access tunnels. This includes the base tunnel as well as various logistics and interconnection galleries and the La Praz safety site.
On the French tunnel entrance in Saint-Julien-Montdenis (CO8), while traditional excavation of the two tubes continues, the installation of the final lining in one of the two galleries passed the 1,000m mark in this month.
On the Italian side, at the Chiomonte (CO3/4) work site, construction of the site platforms is ongoing. This includes building the new soldier-pile walls required for the entrance to the La Maddalena 2 exploratory gallery, the first section of which will be excavated using conventional methods. The new platforms will accommodate the TBM, which has been factory-tested.
Preparation of sites for handling excavated material is also progressing. At Salbertrand, ground-level assembly of the structures for the excavated rock processing plant has begun, while at Torrazza Piemonte, preparatory work is under way on infrastructure for the conveyor system that will transport materials to the disposal site. In Susa, the site platform designed to receive excavated material has been completed, while the associated prefabricated buildings are currently being manufactured off-site.
