The final section of the A86 around Paris comprises two traffic levels, 10 km long, on top of each other in the same tunnel, for use only by cars, drilled with a 10.4 m diameter Tunnel Boring Machine (TBM); an undergroundinterchange midway connects both levels to the surface roads. This innovative project is currently under construction; the first section will be opening in autumn 2007. The project is nothing like anything that has been constructed before and its technical solutions required the setting up of specific committees, as the project, despite its evident qualities, arousedstrong local opposition, often on principle, based on the supposed dangers of its innovative nature. In fact, the final design was based on a search for possible simplifications and on proved techniques: only their use incombination could be considered innovative. The work is being carried outunder a public-private partnership, with its capital cost, estimated at 1.8 billion Euro, financed entirely by tolls, with no guarantee from the State; numerous studies were carried out in order to estimate, and then to control, the risks and to assess the expectations of motorists in this typeof innovative construction, and also their willingness to pay. Finally, the construction work itself posed a challenge, the risks of which have hadto be controlled, both on a technical level, as the route of the tunnel crosses 13 geological horizons and 4 water tables, and on a level of the impact of the construction on the particularly sensitive residential areas to the west of Paris. Cofiroute, an autoroute concessionaire, whose shareholders are the Vinci Group (82.4%) and the Colas Group (17%) was appointed to carry out the work. For the covering abstract see ITRD E139491.
Samenvatting