A retaining wall is a structure designed and constructed to resist the lateral pressure of soil when there is a desired change in ground elevation that exceeds the angle of repose of the soil.

Every retaining wall supports a “wedge” of soil. The wedge is defined as the soil which extends beyond the failure plane of the soil type present at the wall site, and can be calculated once the soil friction angle is known. As the setback of the wall increases, the size of the sliding wedge is reduced. This reduction lowers the pressure on the retaining wall.

However, the term is most often used to refer to a cantilever retaining wall, which is a freestanding structure without lateral support at its top.

The most important consideration in proper design and installation of retaining walls is to recognize and counteract the fact that the retained material is attempting to move forward and downslope due to gravity. This creates lateral earth pressure behind the wall which depends on the angle of internal friction  and the cohesive strength of the retained material, as well as the direction and magnitude of movement the retaining structure undergoes.

Railroad ties are a simple and effective way to keep stones on the wall in place and sturdy.

Retaing Wall

Retaining Wall

Retaining Wall