A quarter of the 164km of tunnels for the Mont Cenis base tunnel have been excavated.
In a new year update, Tunnel Euralpin Lyon-Turin (TELT) said excavation was under way on 14 faces using the conventional method.
At Saint-Julien-Montdenis, excavation with explosives continues on the two fronts from the west entrance of the base tunnel. In November it progressed by 213m, reaching a total of more than 2,560m on the two tubes from the entrance.
Excavation is also continuing in the sixth bypass, which has reached a length of more than 41m.
In the Saint-Martin-la Porte cavern, the head of the TBM has been assembled. This TBM will dig the 9km base tunnel parallel to the one already built by the TBM Federica. Underground excavation between Saint-Martin-la-Porte and La Praz is also progressing on the technical and logistical caverns and some sections of the base tunnel towards both Lyon and Turin.
On the Avrieux platform, the construction of the base tunnel ventilation shafts continues, with a robot applying the concrete lining. This innovative system secures cavities at a depth of 350m without direct human intervention. After consolidating the first shaft, including installing the ‘sarcophagus’ tool to form a metal ring around the walls so that the cavities can be filled in completely, the robot is now tackling the second shaft.
Work on the Lyon-Turin railway is also continuing above ground.
In France, the laying of the railway viaduct over the Arvan River began on December 10. The viaduct in the plain of Saint-Jean-de-Maurienne is part of the works for the railway interconnection with the historic line managed under delegated contract by SNCF Réseau.
This viaduct will allow for a change to seven tracks, compared to the current two.
All the works for the management of excavated material are under construction. The material treatment plant in Saint-Julien-Montdenis is being assembled next to the railway junction. The 5km of conveyor belts that will transport materials between excavation sites, processing sites and storage sites are also being installed.
In Italy, the installation of the first ramp of the new Chiomonte motorway interchange on the A32 motorway is being completed, which will be used to move vehicles from the construction site of the base tunnel, avoiding impacting local traffic.
Also at San Didero, where the new car and truck terminal is being built to replace the one in Susa, the structural element that overlays the A32 motorway was laid at the beginning of December. Now both ramps will have to be connected to the motorway route to link to the car and truck terminal where trucks can stop and refuel before the ascent to the Fréjus tunnel.
The project will be the focus for the British Tunnelling Society’s evening lecture on January 16.
