The diaphragm technique allows the construction of continuous bulkheads in reinforced concrete of over 25-30 m below ground level. Variously arranged in sequences of linear forms, box-shaped, circular or polygonal, are well suited for the construction of tanks for the storage of fluids, underground parking, protections, defences of river banks and subways.
They are built excavating with free grabs (gravity grabs) or with Kelly bars which have a variable width (normally 250 cm) and a thickness between 40 and 120 cm.
Constructed without reinforcement cages and concrete, plastic diaphragms are in fact made of the same bentonitic slurry used for the excavation, with the peculiarity that cement is added in order to give them solidity and integrity over time.
They can be defined as portions of land with changed geo-mechanical characteristics, particularly suitable whenever the action of soil containment, typical of the bulkheads, is faible in favor of the elimination of water flows or fluids in general.