Eiffage Civil Engineering under the Garonne River

With an internal diameter of 2.4 m and a depth of between 35 and 22 m, this gallery, 745 m long, will be used to transport effluent from the right bank to the left bank for treatment.

The work includes :

• the excavation of 745 m of technical gallery with an external diameter of 3 m using the AVND2000AB microtunnelling machine
• the installation of tubes making up the gallery in the starting shaft and pushed along the length of the borehole to their final position
• the S-shaped layout with 2 curves of 400 m radius in plan and 1 vertical curve of 5 800 m radius
• the slalom between the piles of the Chaban-Delmas bridge, the piles of the Bacalan bridge and the old buildings on the left bank

The digging started last November for a duration of 4 months. Once the gallery is completed, the teams will build a pumping station as well as the shell of the reception building.

This project requires the mobilisation of the Hydraulics, Networks and Foundations teams, either 55 employees.

Photos Credit : Eiffage Génie Civil