Building a retaining wall from concrete in a few hours.
The most important consideration in proper design and installation of retaining walls is that the retained material is attempting to move forward and down slope due to gravity. This creates a lateral earth pressure behind the wall which depends on the angle of internal friction (phi) and the cohesive strength (c) of the retained material, as well as, the direction and magnitude of movement and retaining structure undergoes. Lateral earth pressures are typically smallest at the top of the wall and increase toward the bottom. Earth's pressures will push the wall forward or overturn it if it is not properly addressed. Also, any groundwater behind the wall that is not dissipated by a drainage system causes an additional horizontal hydrostatic pressure on the walls.