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puits avrieux raise borer
puits avrieux raise borer

All the construction sites of the Lyon-Turin are advancing on both sides of the border

On 5 October, at the Avrieux platform, the raise borers began with the excavation of the first two pilot holes for the ventilation shafts of the Mont Cenis base tunnel: four vertical shafts through the 500 metres of rocks separating the surface from the underground Modane section of the new line. At the end of November, the excavation of the first two holes, with a diameter of 40 cm, reached a depth of 644 metres out of the 1000 to be excavated. Bars will then be inserted into the holes, at the ends of which the heads of the vertical cutters for digging the shafts will be mounted. In the meantime, underground, at the foot of the Villarodin-Bourget/Modane tunnel access, the excavation of the first kilometre of tunnels making up the system of tunnels and caverns required for the work has been completed; they were all built using conventional methods.

Meanwhile, on 3 October, the SMP4 construction site in Saint-Martin-la-Porte, which has accompanied the Lyon-Turin line from the geognostic investigation phase to the definitive works, was definitively closed. However, this area remains the protagonist of the excavation of the Mont Cenis base tunnel: here the companies of the Vinci Grands Projets – Dodin Campenon Bernard – Vinci Construction France – Webuild grouping, already operating on the La Praz platform, will now have to complete the 23 km of tunnel to reach Modane. 

The companies are preparing for excavation works in Saint Julien-Montdenis too: after the completion of the first part of the entrance portal of the base tunnel, the lowering of the tunnel entrance berm and the consolidation of the ground at the point where excavation of the tunnel into the mountain will begin in December have also been completed. The development of the platforms continues with the construction of water treatment basins, the assembly of the second concrete plant, and the construction of hangars for logistics and maintenance. In addition, the construction of an acoustic hangar in the entrance portal extension is under way. Finally, the assembly of the conveyor belt that will transport excavated material from the construction site to the Resses site has begun.  

SNCF Réseau‘s work continues above ground in the Saint-Jean-de-Maurienne plain, where the construction of the new Electricity Substation powering the historic line has been completed. The current substation will be demolished in 2023.

On the Italian side, the inspection and equipping with the use of the Axel rover from PK 4+130 to the bottom of the Maddalena tunnel in Chiomonte was successfully completed.  Having completed 9 niches, excavation of the remaining interchange niches for the work vehicles continues. Outside, the areas were handed over to the motorway concessionaire Sitaf for the construction of the site junction on the A32 Turin-Bardonecchia motorway. In San Didero, Sitaf, which operates under an agreement with TELT, has started the demolition of the existing buildings in the area where it will build the new truck and car terminal to replace the one in Susa. Finally, the cleaning up of the area in Salbertrand, which will house the segment factory continues. The factory will process the excavation materials from the base tunnel.

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