A diaphragm wall is a structural concrete wall constructed in a deep trench excavation, either cast in situ or using precast concrete components.
Diaphragms walls are often used on congested sites, close to existing structures, or where the excavation is of a depth that would otherwise require the removal of much greater volumes of soil to provide stable battered slopes.
The wall is usually designed to reach very great depth, sometimes up to 50m, mechanical excavating method is thus employed.
Uses of Diaphragm Wall :
1) As a cut-off provision to support deep excavation.
2) As a retaining wall.
3) As the final wall for basement or other underground structure (e.g. tunnel and shaft).
4) Used in congested areas.
5) As a separating structure between major underground facilities.
6) As a form of foundation (barrette pile-rectangular pile).
7) It can be installed in close proximity to existing structures.
Advantages of Diaphragm Walls :
1) Diaphragm walls can be constructed in thickness ranging from 100 mm to 1200mm.
2) It can be installed to considerable depth.
3) It provides flexible system in plan layout.
4) It can be designed to carry vertical loads.
5) It saves construction time of basement.
6) It can be used for seepage control in earthen dams.
7) It can be constructed in unsuitable soils below water table.
8) It can be easily incorporated into permanent works.
9) No vibrations produced during installation.