Retailing walls are built for the purpose of restraining soil to unnatural slope. They retain soil lying between two regions of uneven elevations. The areas they are constructed vary. They are often constructed in places where engineering and shaping needs to be done severely for functions like hillside farming and roadway overpass. Other area where a retaining wall may be constructed is a place where there is an undesirable slope.

These walls come in many types. Common examples are gravity, cantilever, anchored, and piling walls. Their purpose is supporting a wedge of soil. The retained soil tends to shift downslope because of gravitational pull. As such, the design and construction must be done in a way as to counteract this tendency. Gravitational pull results in lateral earth pressure in the supported material. How much pressure is generated varies with the angle of friction and cohesive strength of retained material.

The mass of gravity walls play a major role in their ability to resist pressure they get exposed to. They are made heavy using concrete and stones. Incorporation of batter setback helps to improve stability. They may be constructed in a way as to lean towards the load they support. Dry-stacked varieties are made flexible with flexible footings when they are made in frost prone region.

In the earlier years of the 20th century, tall retaining walls were of the gravity type. They were made from large masses of stone or concrete. Modern-day walls get made from composite material. Some common materials they are made from include crib walls, gabions, and soil-nailed walls. Gabions are composed of stacked steel wire baskets that are filled with rocks.

The making of cantilevered retaining walls involves the use of internal stems of steel-reinforced, cast-in-place concrete, and mortared masonry. In some circumstances, buttressing is done to the front side. More strength for supporting heavier loads is achieved through the addition of counterfort. Fronts may also be buttressed. Buttresses resemble wing walls and their installation is done perpendicularly to main walls. It takes less construction material to make cantilevered walls in comparison to gravity walls.

Tight spaces and soils that are soft are suitable with sheet pile retaining walls. This variety is made from various materials including vinyl, wood planks, and steel, which are driven underground. About two thirds of the material stands above the ground while a third is driven underground. The measurement of material driven underground and the one remaining above may be varied depending on the situation.

Bored pile walls are built by assembling a series of bored piles. Excess soil in the construction site must be excavated first. The construction process employs many techniques and processes including soil enhancement operations, reinforcing beams, earth anchors, and shotcrete reinforcement layer. Bored pile walls can be built anywhere where sheet piling walls are feasible but cannot be built as a result of excess vibration and noise the process involves.

A lot of evolution has occurred in construction styles. The methods of reinforcing the walls are also many and diversified. Some of the commonly used retention methods employed are cellular confinement, soil-strengthening, soil nailing, and gabion meshes.