France – Construction work for bridges and tunnels, shafts and subways – Chantier 5 : Marché de travaux pour les travaux d’extension du réseau de galeries du Laboratoire de recherche souterrain et les travaux associés.

Andra plans to undertake a new underground gallery network extension project, as well as carry out improvement works in existing galleries, referred to as "Project 5", which is the subject of this consultation. Project 5 involves:

- Continuing the development of the underground gallery network at – 490 m over approximately 530 m with:

- Excavation and support of 3 galleries in arched section S4 (Ø 5.70 m)

- Excavation and support of an X-shaped junction in section with compressible wedges S9 (Ø 6.70 m);

- Full-section excavation and support of the extension of gallery GGS (Ø 10.50 m);

- Full-section excavation and support of an X-shaped junction in section with compressible wedges S12 (Ø 10.50 m);

- Civil engineering works for lining (approximately 50 cm thick) of gallery GGS, two X-shaped junctions and the existing gallery GHA with prior installation of compressible materials;

- Civil engineering works in the existing gallery GRD6;

- Ancillary works, such as the construction of works related to the HA cell demonstrator program in galleries GER2 and GHA (opening of support, bearing blocks and mooring blocks)

- Civil engineering works related to the experimental and demonstration testing program (other than HA cells), and related to fire studies (such as the installation of fire partitions, for example)

- Continuing the development of the underground gallery network at – 445 m over approximately 40 m, as well as potentially related civil engineering works for Andra's needs with:

- Excavation and support of 2 galleries in Ø5.70 m

- Excavation and support of a widened section in Ø6.70 at the end of one of the 2 galleries.

Other preparatory tests may be requested. These tests may take place in the underground laboratory, on surface installations, on one of the external sites attached to the CMHM or any other external site at Andra's request.