TBM “Roberta” Begins New Life on Grand Paris Express Line 15 West
Its name is “Roberta.” This tunnel boring machine (TBM) will excavate approximately 7 kilometers of tunnel as part of Lot 2 of Line 15 West of the Grand Paris Express, the largest urban mobility program currently under construction in Europe. The project is being delivered by NGE (lead contractor) and Webuild as part of a joint venture on behalf of Société des grands projets. The TBM was officially named Oct. 7 during a ceremony organized by the project owner, Société des grands projets, in Gennevilliers, in the Paris region.
The TBM was named in honor of Roberta Arrigoni, an architect at Webuild who has spent 37 years working on the design and delivery of complex infrastructure projects in Italy and internationally. She joined the Webuild Group more than 10 years ago and has been involved in the Grand Paris Express since its launch. Today, she plays a leading role in the delivery of Lot 2 of Line 15 West, as part of the joint venture formed by NGE, Webuild and Equans France.
The story of “Roberta” also illustrates an industrial model based on circular economy principles. Before being assigned to Line 15 West, the TBM had already successfully completed the excavation of 5.8 kilometers of tunnel for Lot 2 of Line 16 of the Grand Paris Express. Following that project, rather than being decommissioned, the TBM was transferred to Italy and completely refurbished by Webuild at a facility in Terni, a center of excellence specializing in the refurbishment and recommissioning of large TBMs and other tunneling equipment.
Through a comprehensive overhaul, technological modernization and technical adaptation program, the TBM was prepared to meet the specific geological and operational conditions of this new section of the project. This approach extends the machine’s useful life and transforms an already-used piece of equipment into a resource ready to begin a new phase of construction.
More than 100 meters long, with an excavation diameter of 9.86 meters and weighing nearly 2,000 metric tons, “Roberta” reflects Webuild’s expertise in the design, operation and refurbishment of tunnel boring machines. Reusing the TBM made it possible to avoid manufacturing a new machine, thereby reducing the consumption of raw materials and the environmental impact associated with its production. This approach fully aligns with an increasingly circular economy model and the responsible use of resources.
Sustainability is at the heart of the entire Lot 2 project of Line 15 West. The tunneling works will generate approximately 500,000 cubic meters of excavated material, nearly 80% of which will be recovered and reused. These materials will be transported via the Paris region’s inland waterway network, avoiding the equivalent of approximately 64,000 truck journeys and helping to reduce road traffic, emissions and disruption associated with urban mobility.
The same approach has been adopted for the tunnel lining. Approximately 23,000 precast segments will be produced as part of the project, around 79% of which will be made using fiber-reinforced concrete. This technological solution significantly reduces the amount of steel required while maintaining high levels of safety, strength and durability.
Through the Grand Paris Express, NGE and Webuild are reaffirming their position among the global leaders in the delivery of complex underground infrastructure. Together, the two major players have already delivered some of the program’s most significant sections, including the southern extension of Line 14 to Orly Airport, with 4.1 kilometers of tunnels, and Lot 2 of Line 16, involving the excavation of approximately 11 kilometers of tunnels.
