Port and waterways
Dry dock No. 1 in Brest is the smallest and oldest of the dry docks in the commercial port of Brest. Built in the 1900s for the ships of that era, the facility has become impractical for repairing modern vessels. The project led by the Finistère Departmental Directorate of Equipment (DDE) therefore involves widening and refurbishing it.
Geotechnical surveys carried out in 2004 enabled the description of the caissons, the foundation slab and the surrounding ground, and assessed the reliability of the archive data documenting the structure’s history. A study of the tidal hydraulic regime was also carried out through the continuous monitoring of piezometers and interstitial pressure cells installed in the structure’s masonry (walls and foundation slab).
These diagnostic findings led to the decision to opt for a solution involving widening via a diaphragm wall constructed behind the southern pier, which will subsequently be demolished.
The key challenges of the project relate to:
- anchoring the wall in highly heterogeneous soil and highly fractured rock, and its connection to the breakwaters,
- the widening of the foundation slab and its connection to the new wall
- the stability of the asymmetrical entrance after works
- maintaining the overall stability of the structure and its hydraulic regime
From 2005 to 2007, TERRASOL advised the Project Manager on the design studies, the preparation of the tender documents and the supervision of the widening works.
Project Manager
Finistère Regional Directorate of Public Works – Maritime and Airport Services
Client
Finistère Regional Public Works Department
Miscellaneous
- Width of the original structure: 27 m
- Width of the structure after works: 34 m
- 180 m of diaphragm wall
