Agent Access 
Terrasol participated in the design of a test tank for submarine armament. It is a 30m diameter very deep circular tank, filled with fresh water.
The installation includes: the structure of the tank itself, secondary civil engineering structures intended for the handling equipment required to perform the test, at 1000m² technical building, and all the industrial equipment required to operate the installation.
The poll itself is made of:
- a diaphragm wall (see picture),
- a crown beam to make the structure rigid,
- a 1.80m thick raft,
- a pre-stressed inner lining taking up internal excess pressures, separated from the diaphragm wall by a draining system.
As submarine tests are filmed, the tank water (several tens of thousands cubic meters) must keep good optical quality over time. An installation for water treatment, based on recirculation, filtration and chlorination, ensures this requirement is met. It also removes pollution created in the water when performing the tests. This installation takes up a 600 m² hall in the technical building.
A European record: The diaphragm wall technique was chosen because it allowed to minimise technical hazards and to secure the deadline.
Geotechnical soil surveys led down to 120m depth enabled to identify a semi-impermeable layer below 70m depth. The 120 cm thick diaphragm walls were embedded into that layer to ensure an impermeable containment. They are the deepest in Europe.
Terrasol’s achievements:
- Designed of the equipment based on functional specifications,
- Preparation of contracts,
- Analysis of the tenders,
- Works follow-up,
- Visa for detailed design
