Is there a risk of land subsidence above the tunnel?

Many transport projects have required the digging of tunnels in recent years in the Île-de-France region. Proven civil engineering techniques and the experience of the project managers and project owners ensure the safety of this work.

As part of the extension of the T7, geotechnical surveys were carried out in order to perfect the knowledge of the subsoils of the Parc de la Mairie. These investigations have made it possible to remove all questions concerning a potential risk of land subsidence. However, additional surveys will be carried out before the work in order to finely consolidate the analysis of the underground ("gypsum lenses") in the immediate vicinity of the tunnel.