The work and the technique: Line 16 of Grand Paris Express, France

In a joint venture with Nouvelles Générations d'Entrepreneurs (NGE), Webuild won the project for Line 16 Lot 2 of the Grand Paris Express metro system.

Two TBMs (Tunnel Boring Machines) are excavating the tunnels: Houda, which left Aulnay – Val Francilia in autumn 2020, and Mireille, which started excavating in April 2021 at Chelles, on the opposite end of the line.

In May 2023, Mirelle concluded its journey with the last breakthrough that occurred in the Mare au Chanvre construction site in Sevran, a town north of Paris. The TBM has therefore completed the first 5.3 km of the tunnel that will connect Chelles and Sevran. It left from the Bel-Air a Chelles construction site, at the extreme southern end of Lot 2 and was then dismantled and the exit shaft was set up to welcome Houda's arrival. At the beginning of March 2024, al excavations of Lot 2 were completed. The Houda TBM terminated in the Mare au Chanvre construction site, in the northeastern part of the city.

The digging operations have had to face and resolve various geotechnical issues, such as the presence of chalk and green 'swelling' clays. The route also features innovative materials: the inner lining of the tunnels is made of fibre-reinforced concrete, a composite material of iron fibre elements to reinforce the characteristics of cement concrete, used for the first time in the construction of tunnels in France.