Ligne Ferroviaire Lyon-Turin, Lot 2 - VINCI Construction Grands Projets

Context

Lyon-Turin is a new rail line for the transport of goods and passengers, 270 km long, 70% of which is in France and 30% in Italy. It is the central link in the Mediterranean corridor, one of the 9 stretches of the TEN-T trans-European transport network, which extends over 3,000 km and links 7 European corridors from east to west. The line is divided into three sections:

the joint cross-border section between Italy and France, from Susa (Piedmont) to Saint Jean de Maurienne (Savoie), under the responsibility of the Franco-Italian public contracting authority Tunnel Euralpin Lyon-Turin (TELT), whose main structure is the 57.5 km Mont Cenis base tunnel, currently under construction;
the Italian part, from the Turin junction to Bussoleno (Susa Valley), under the responsibility of RFI;
the French section, from Saint-Jean-de-Maurienne to Lyon, under the responsibility of the SNCF.

The Lyon-Turin rail line project was born with environmental objectives based on the:

Alpine Convention (1995) providing for measures to reduce road traffic in the Alpine arc;
Paris Climate Change Conference (2015), which encourages the reduction of greenhouse gases.

Technique

The work on the cross-border section between Saint-Jean de Maurienne and Susa in Italy is divided into 81 calls for tenders spread over 12 operational sites:

9 for Alpine crossing works, subdivided by geographical area (4 in Italy and 5 in France), between the interconnections with the historic line in Italy and France;
2 for the recovery of excavation materials in Italy and France;
1 for technological equipment and safety.

The consortium comprising VINCI Construction Grands Projets (leader), Dodin Campenon Bernard, Campenon Bernard Centre Est and the Italian builder Webuild has been awarded operational projects 6 and 7.

The contract covers the excavation of 25 km of the base tunnel using 3 tunnel boring machines and 21 km using conventional methods (explosives and mechanised means). It is important to note that, in addition to the two main tubes in which the trains will travel, the excavations include the creation of 71 safety tunnels and various galleries, including technical «caverns» over 20 m high.

The first tunnel boring machine will dig just over 8 km towards Italy from the existing Saint-Martin-La-Porte descending shaft (CO7).

The other two machines, due for delivery in October and November 2023, will leave from the La Praz descending shaft (CO6) and advance to Villarodin/Bourget-Modane.

All access for materials, equipment and personnel during the construction phase will be via these two descending shafts.

Launched in late 2021, the project will take 8 years to complete and will employ 2,000 people.

Logistics is a major challenge. Material flows will be very important: in terms of incoming flows, we have to transport the components needed to assemble the tunnel boring machines, thousands of tunnel segments (95,000 prefabricated components in total) and large volumes of concrete for lining and supporting the tunnels (2 million m³ in total).

For the outgoing flows, we will have to evacuate huge quantities of rubble (4 million m³) via 55 km of conveyor belts.

Impact

The Lyon-Turin line will relieve the Alpine roads of 1 million heavy goods vehicles and reduce greenhouse gas emissions by around 1 million tonnes of CO₂ equivalent every year.

Reducing pollutant emissions in the Alps is one of the main objectives set by COP21, the climate conference held in Paris in 2015, which reaffirmed the need to shift 30% of goods from road to rail by 2030 and 50% by 2050.