ABSTRACT
The Mont-Blanc tunnel is operated by a consortium, the GEIE-TMB. It has been operating, maintaining and making the necessary investments since its creation in 2002. It provides all continuous monitoring and inspection operations of civil engineering structures inside the tunnel. This regular monitoring made it possible to detect the need to renew the concrete slab over a 555 metre section in the centre of the tunnel. This contract, attributed to our consortium (Spie batignolles Génie civil/Cogeis/Setec Als) in June 2017, is part of the ongoing safety operation of the structure, a major challenge for the GEIE-TMB. Our group proposed a solution based on an innovative technology: a design of the new prefabricated slabs and the use of two gantries developed for the site. This system enabled us to work mainly at night, during 32 traffic interruptions, while ensuring that the tunnel reopened every morning.
