Activities in France

The excavation of the Mont Cenis base tunnel access, on the French side, in Saint-Julien-Montdenis, is in progress and the first 2km inside the mountain were completed. At the same time, the companies started the works for the definitive lining of the tunnel.

The preparation of all necessary structures started in the summer of 2024 with fire tests in the laboratory on full-scale models of the future final lining that simulated temperatures of up to 1350°C. Subsequently, last February, the first of two tailor-made tools to waterproof, reinforce and cast the inverted arch (i.e. the base) of the base tunnel was tested in Slovenia. After being dismantled and transported to the construction site, the tool was reassembled on the platform and moved to the tunnel the following month, where it has already completed the first 142 metres of the south tube.

Furthermore, at the Avrieux construction site, where the four 500-metre-deep tunnel ventilation shafts are being built, after the completion of the excavation and temporary lining, the final phase for the final lining of the first shaft has begun. The work includes the sealing, reinforcement and completion of the final lining – with a final thickness of 25 cm – in this case starting from the bottom, i.e. form the base chamber at the foot of the Villarodin-Bourget/Modane access adit going upwards.

In Saint-Martin-la-Porte and La Praz construction sites the excavation is proceeding on the different fronts: south tube of the base tunnel, technical caverns necessary for mechanised excavation, communication branches. Meanwhile, the Viviana TBM is completing its rotation towards the face in order to start excavating from September.

Activities in Italy

TELT sent the Phase 2 Executive Project, which analyses the implementation of the project already approved to the ministries and relevant agencies. The activities concern the Chiomonte/Giaglione, Susa and Salbertrand construction sites.

In Chiomonte, the new junction of the A32 motorway, which will allow the transit of construction vehicles via the motorway, is almost complete and the group of companies has ordered the first TBM, which is being built at the Herrenknecht factory in Germany.

The arrival of the TBM, scheduled for 2026, will be preceded in the coming months by preparatory activities: the UXT group of companies will build the bulkheads and lower the forecourt by a few metres at the entrance, before starting the excavation of the first metres using the traditional method.

In Salbertrand, the preparation is in progress, with ordnance clearance and the definition of the road routes, of the area where the segment factory and the construction site for the reuse of the excavated material deriving from the works of the base tunnel on the Italian side will be built. On the other hand, part of the pre-processed material from Salbertrand will be temporarily stored in Susa. The areas in Susa are the same on which the international station, the technical area and the ancillary works will later be built.

The construction sites are being prepared and will be operational at the same time as the start of excavation of the base tunnel, scheduled for 2026.