This European Standard specifies the execution of diaphragm walls and the practical aspects which must be taken into account in the production of the working drawings. Diaphragm walls can be permanent or temporary structures. The following types are concerned :1 -retaining walls : usually made to support the sides of an excavation in the ground. They include : - cast in situ concrete diaphragm walls ;- precast concrete diaphragm walls ;- reinforced slurry walls ;2 cut-off diaphragm walls : usually made to prevent migration of groundwater, clear or polluted, or of other liquids present in the ground. They include :- slurry walls (possibly with membranes or sheetpiles) ;- plastic concrete walls.