A diaphragm wall may be described as an artificial membrane made of reinforced concrete constructed in the ground by means of a process of trenching with the aid of a fluid support. The most popular use of a diaphragm wall is for the construction of multilevel basements.
The Origin of the diaphragm wall can be traced to the post war years in Italy (early 1950's) where adjacent reinforced concrete piles (known as secant piles) were used to construct a barrage or a cut-off wall for hydroelectric dams. To answer the need for increased water-tightness which could be provided by minimizing the number of vertical joints and due to the fact that the secant pile technique involved the partial destruction of a completed pile by the boring of an overlapping pile (a seemingly wasteful technique)a more elegant solution of excavating a trench in sections in which to cast a series of in- situ adjacent reinforced concrete panels was developed.
The application of the diaphragm wall technique was gradually extended to solve problems involving the building of underground tunnels for rapid transit systems along busy streets, construction of deep basements without endangering the stability of the foundations of the nearby buildings, and the construction of closed-type docks and wharfs.