ABSTRACT
A new road tunnel is needed within the project of the modernization of the South-East European Technicentre. It consists of a limited-length tunnel (50 meters) to be performed in conventional excavation below Poniatowski Avenue (Paris). The excavation, crossing the entire width of the boulevard constitutes a major challenge, given the very low soil cover (< 5.5 m) and the surrounding infrastructures. The design challenged several aspects of its execution, and particularly, continuous operation must be guaranteed to the neighboring networks during the works. The installation of an umbrella-pipe, the progression in divided sub-sections, and the implementation of a monitoring system are key elements for limiting and controlling any deformation. The observational method is used to pilot the excavation depending on the deformations measured and the ground behavior. Back-analysis of the two side galleries excavation has been performed to compare the real deformations with the 3D finite element modelling results.
