Fréjus safety tunnel

Matea Uhlik Vidović, 14.07.2016.
The Fréjus Road Tunnel linking France and Italy. It runs under Col du Fréjus in the Cottian Alps between Modane in France and Bardonecchia in Italy and is parallel with Fréjus railway tunnel. The 12,87 km’s construction, for which the cost climbed to 700 M euros, started in 1974 and was open for the traffic in 1980. The tunnel can be reached from the Italian side from Torino-Bardonecchia motorway, or by Oulx, and from the French side, it can be reached from Lyon and Chambéry.  The new second tube was originally designed as a safety tunnel - in accordance with the regulations considering the fire disaster of the tunnel Mont-Blanc in 1999. Work of the second tube started in 2009 and excavation, which was commenced to comply with EU directives for tunnels included in the Ten-T network, begun in 2011.

Fig. 1 Tunnel Fréjus


Fig. 2 Cross-passages of the tunnel

The second tube is 12.9 km-long (6.5 km in France and 6.4 km in Italy), construction was completed in 2014. and it will enter into service in 2019, making the Fréjus tunnel the longest double tube road tunnel in Europe. Total Project cost is about 400 M€, shared between French Society of Fréjus road tunnel (SFTRF) and his Italian counterpart, the Società Italiana per il traforo autostradale del Fréjus (SITAF). This second tube has become, over the progress of the project, a tube carriageway road reserved for the movement of light vehicles and trucks in the Italy-France. The existing tunnel, a distance of 50 m, will, meanwhile, devote to traffic in the France-Italy, its second channel becoming an emergency lane. The project involves the construction of a safety tunnel and passageways connecting with the existing road tunnel along which new emergency shelters can be built. The Fréjus tunnel consist of one-way lane in each direction and has a diameter of 8 m.

This dimension has been designed from the start to create a second flow tube as was foreseen and denounced the environmental protection organizations at the time of the public inquiry. The construction of civil works was divided into two lots: Lot 1 for the works on the French side, and Lot 2 for the corresponding works on the Italian side. On the Italian side the excavation began with the traditional method. Based on good progress with TBM on French side it was decided to continue the entire excavation of Lot 1 by the French side. The characterization of the geological and geomechanical context of the tunnel is: high overburden from 800 to 1800m, the ground is mostly composed from Triassic series, the calc-schist formation and of limestone shale which was crushed by disc cutters mounted on the head of the tunnel borer. The construction of the second Fréjus tunnel also includes the completion of 34 100 m² security shelters in the inter-tubes, creation of 5 bypass passable between the two galleries for the passage of teams and emergency vehicles as well as 34 by-pass with the purpose of the 'safe area'. Until 2019, the work will also include the construction of 8 technical stations and two ventilation plants, what will allow regulatory level of the new infrastructure.