A retaining wall retains soil similar to how a dam retains water. A dam’s mass must be large enough to withstand the pressure of the lake that it’s holding back. A retaining wall’s engineering principles are similar. Even though earth doesn’t move as fast as water, it still applies pressure to a retaining wall just as water does to a dam.
Dams and retaining walls are also similar in how they are designed. Many dams are created using compacted soil that is protected with concrete or rocks. Retaining walls use a similar design where engineers combine compacted soil with geogrid. Geogrid is a structural building material that helps consolidate the soil into a stronger mass. It’s a similar concept as putting rebar into concrete. The combination of soil and geogrid makes a perfect structural reinforcement for retaining it all. The concrete retaining blocks are the finishing material that adds beauty and provides protection to the soil mass.
A properly designed retaining wall will last a lifetime as long as the compacted mass is protected from water saturation and erosion. Engineers design many features into their designs to protect it from these situations. Properly designed retaining wall structures provide pathways to remove excess water from the base and also behind the wall facing.