ABSTRACT
The Grand Paris Express is one of the biggest infrastructure projects of the century in Europe. Among the four new lines, which are planned to be completed before the Paris Olympic Games in 2024, the extension of line 14 will connect the capital and the Orly airport. Built entirely underground, the extension is composed of 14 km of underground tunnel, 6 stations and 12 shafts. One of the major technical complexities is the tunnel excavation under the limestone old exploitation quarries. To control ground settlements and to secure the excavation using an EPB TBM, it was decided to grout all the quarries above the tunnel. Finite element calculations have been performed in order to determine the extension of the ground treatment (size and type). The grouting work in a dense urban environment has been a major challenge requiring minimizing the disturbance on residents despite the coactivity of several grouting sites.
