This European Standard establishes general principles for the execution of diaphragm walls as either retaining walls or cut-off walls. NOTE 1 This standard covers only structures constructed in a trench excavated with a support fluid or in dry conditions, where soil is removed and replaced by concrete or slurry and with wall thickness B + 40 cm. NOTE 2 Diaphragm walls can be permanent or temporary structures. NOTE 3 The following types of structure are considered:a) retaining walls: usually constructed to support the sides of an excavation in the ground. They include:1) cast in situ concrete diaphragm walls;2) precast concrete diaphragm walls;3) reinforced