Will there be any nuisance (noise, vibrations, deterioration of houses) during the work on the tunnel boring machine and the construction of the structures?

The digging of a tunnel requires rigorous measures to minimize the impact on the environment and local residents. Geotechnical risks and associated nuisances require a methodical approach and appropriate measures.

In general, Île-de-France Mobilités is vigilant in integrating these aspects from the earliest design phases of the project, as part of the "ERC" approach (avoiding, reducing, or compensating for the project's impacts on the environment and human health).

Île-de-France Mobilités can rely on the many recent feedbacks from tunnel projects. The tunnel route is designed to avoid underground quarries as much as possible, thus reducing the risk of instability and the need for specific soil treatments. In addition, special attention is paid to interfaces with existing structures, including underground car parks and building foundations. Acoustic and vibration studies will also be carried out on the basis of the selected scenario to specify the impacts of the project and define the appropriate measures. In-depth geotechnical investigations are carried out at each phase of the project. Buildings in the vicinity of the route will be classified according to their sensitivity to vibrations: for each level of sensitivity, a maximum vibration threshold to be respected will be defined and the tunnel construction methods will be defined in such a way as to comply with these thresholds. Pre/post inventories are provided to check that there are no disorders on the buildings, and this type of site is closely monitored throughout its progress.

To limit the nuisance of the construction site, several measures are being considered, including:

• Prior identification of sensitive areas and the vulnerability of the building in the vicinity of the route and structures (houses, buildings near the site) in order to adapt construction techniques.

• Maintaining sufficient thickness above the tunnel to ensure the stability of the buildings and limit the impact of vibrations.

• Adaptation of construction techniques according to the nature of the ground and the buildings on the surface.

• Specific studies carried out to assess and anticipate the impacts of the site (noise and vibrations) as well as possible

• Measures to reduce the effects of the construction site (for example, installation of anti-vibration pads to absorb shocks).

• Implementation of preventive summary proceedings before the start of the work.