Drainage system for wall of underground installation has inlet for period application of descaling solution such as polyphosphate

摘要

The system for draining an underground wall (8) covered by an impermeable layer and fitted with a drainage system of branch (30D) and main (30A) pipes with an outlet (38), incorporates an inlet (42) for periodic application of a descaling solution, e.g. of polyphosphate, for removing calcareous deposits from the surfaces of the drained space. The drainage system extends over all or part of the side wall and along at least part of the vault supported by it. The impermeable layer can be of electro-injected resin or fibres for enhanced performance.