Rennes metro: France's largest civil engineering worksite

From left to right : Jérôme STUBLER, Directeur général de VINCI Construction, Manuel VALLS, Premier Ministre, Nathalie APPÉRÉ, Députée-Maire de Rennes, Emmanuel COUET, Président de Rennes Métropole, la marraine Karine PUYJARINET, Responsable QPE Dodin et Guy MALBRANCKE, DG Semtcar et au 2ème plan : Xavier GRUSON, directeur de projet Dodin

19 December 2014 - Projects update and handover - France

On 19 December, the tunnel boring machine was baptised "Elaine" at a ceremony attended by Prime Minister Manuel Valls. The baptism was among the last preparations in the run-up to the construction phase of the 8 km tunnel for the second Rennes Métropole automated metro line, which is scheduled to begin operating at the end of 2019. The iconic project provides a preview of the upcoming Grand Paris programme.

The second Rennes metro line is currently France's largest civil engineering project being carried out for a regional authority. The line, which will serve 15 stations and connect the southwestern and northeastern parts of the urban area, will open at the end of 2019.

Elaine will drive an 8 km long deep tunnel

On 19 December, a milestone was reached with the baptism of the tunnel boring machine Elaine at a ceremony attended by Prime Minister Manuel Valls and all the project partners. The 82 metre long, 1,450 tonne TMB will begin driving the 8 km long metro tunnel at a depth of more than 20 metres in early 2015. Working at an advance rate of about 300 metres per month, it is expected to break through in 2017. Elaine, the Line B TBM, is three times as powerful as the TBM used to build Line A in the late 1990s.

The TBM will dig through the subsoil like a giant grater at a depth of at least 25 metres, operating 24 hours a day, 7 days a week. As it moves forward, it will install the concrete rings, called arch liners, that will make up the tunnel wall. All arch liners will be brought in by mine cars travelling through the tunnel. In the opposite direction, a conveyor belt will remove the muck excavated by the TBM; the belt will be lengthened as the work progresses.

(Image © SEMTCAR)

VINCI's expertise used to build Rennes' infrastructure

Line B of the Rennes metro is designed to support the expansion of the urban area by providing a transport network meeting social, economic and environmental objectives. Ridership on the Rennes network (STAR) increased from 33 million in the year 2000 to 74.7 million trips in 2013. With the creation of Line B, the traffic forecast for 2020 is 120 million trips. Construction of the line will generate 5,500 direct and indirect jobs.

In October 2013, Rennes Métropole awarded the contract covering underground works (works package 2) for Line B of the Rennes metro to a joint venture led by Dodin Campenon Bernard (VINCI Construction), which specialises in underground works, pour réaliser and including two VINCI Construction France subsidiaries, GTM Ouest and Botte Fondations, as well as Spie Batignolles TPCI, Spie Fondations and Legendre Génie Civil.
The advent of a new type of tunnel boring machine in the 1980s shortened construction times, marking a major change in underground works in France. In 1982, the use of a bentonite slurry tunnel boring machine during the construction of the Lyon metro under the rivers Rhone and Saône – a first – gave Campenon Bernard (VINCI Construction) an opportunity to gain experience in the technique. This success put VINCI on the map and brought the Group contracts for major projects and support missions around the world. For over 20 years, VINCI Group companies have been helping to develop rail transport systems throughout the world, including the metro systems in Marseille, Toulouse, Lille, Lyon and Paris, France; Caracas, Venezuela; Budapest, Hungary; Algiers, Algeria; Athens, Greece; Cairo, Egypt; Dubai, United Arab Emirates; Hong Kong, China; and Doha and Lusail, Qatar.