Webuild and its French partner, NGE, have completed excavation on Lot 2 of Paris’s new metro line.

The breakthrough at Mare au Chanvre marks the end of tunnelling on the 29km-long tunnel for Line 16.

TBM Houda was the last of seven TBMs to finish its journey on the tunnel. Houda and sister TBM Mirelle excavated an 11km section of the tunnel. Mirelle arrived at Mare au Chanvre in May last year.

Lot 2 also includes four of Line 16’s 10 new stations: Aulnay-sous-Bois, Sevran-Beaudottes, Sevran-Livry and Clichy-Montfermeil.

Webuild said the Lot 2 works should be completed by the autumn.

Société des Grands Projets said excavating the 29km tunnel was challenging, with complex geology and “numerous water tables”, and the alignment navigated existing rail lines.

Webuild said using precast fibre-reinforced concrete segments for the tunnel lining halved the amount of steel and improved the strength of the tunnel.

Line 16 is part of the Grand Paris Express, a 200km network to link the city centre with urban areas.

To create the Grand Paris Express, the existing Line 14 is being extended and four new metro lines – 15, 16, 17 and 18 – are being built. Commissioning is due to start this year and be completed in 2030.