The 1.7km-long Meudon Tunnel will be driven through marl and clay, and will be equipped with a combination of rippers and disc cutters. The tunnel will be lined with 1.3m-long precast SFRC segments in a 5+key arrangement for a 3.5m i.d.

As the TBM will bore a non-through tunnel, the machine has been designed to be dismantled within the underground work. Additionally, it has been adapted for a small launch area on the surface.

A spokesperson for Bessac told Tunnels and Tunnelling, “The TBM has been designed to be very compact, and we achieved a 67m overall length. We managed this during the design stage by focusing on the arrangement of the backup section, merging some facilities and reducing the space required to house them, compared with independent installations.

“No concessions were made, and overall the machine complies with the local applicable regulations, standard and safety norms. We don’t want to give further details, so that we do not lose a competitive advantage for the future.”