A wall used to retain some material on one or both sides of it can be termed as retaining wall. Commonly, it is used to retain soil at two different levels on either side of the wall. Therefore, the materials to be retained on either side may be different, e.g. the wall of a swimming pool retains soil on one side and water on the other side. When the material retained by it is fluid say water, it is called a dam.
Gravity wall, cantilever wall, and buttress wall are some of the common types of retaining walls. In the case of Gravity Wall, the self-weight of the structure provides stability against the pressure of retained earth. Cantilever wall consists of the vertical arm that retains the earth and is held in position by the base slab. In this case, the weight of fill on top of the heel, further to the weight of the wall and contributes to the stability of the structure.
The procedure of design of a retaining wall commences with preliminary proportioning of the wall, and then the design is checked against the stability requirements of wall and is revised if required.