The basic function of retaining wall is to retain the earth slopes by 90 degrees “slope,”
whereas the earth natural has sloping sides naturally ,self retaining at 30 to 60 degrees, the slope depends on the property of the spoil.
Principles and Terminology
The function of the retaining wall is to retain the earth vertically rather than let the earth lie in its natural slope ranging from 0 degrees slope to 60 degrees. If the profile of slope is created by cutting the slopes of the earth the slopes angles may even be about 60 degrees. If the ground are hard the profile may be even 90 degree vertical, but unfortunately not all ground are made of solid rock, there for a retaining wall serves the purposes of creating a vertical wall.
*For slopes that are created by filling of the earth, the slope may be 45 degrees to 30 degrees. Again this slope has to do with the character and properties of the earth.
The retaining walls helps to resist the overturning, slipping of the earth. In designing the retaining walls, the following considerations will have to be considered:
- Nature and type of soil
- Height of the retaining walls
- The type of material the retaining wall is constructed off( eg concrete, timber shoring, steel shoring, stone walls, brick walls , keystone walls, etc
- The amount of water flow, or water content in the soil. The water table height is necessary as this will increase lateral pressure on the retaining walls
Types of retaining walls
There are about 5 types of retaining walls, namely:
1.Brick retaining walls
Wall constructed using brick wall, such as drainage, or wall which are cement rendered with stucco or rough finishes to create a special effect externally.
Walls that are constructed using concrete, the height of these wall can be high, the only set back using this walls are the cost of construction and the spaces needed for shoring when constructing these walls is much as it goes higher,
The walls are usually used for gardens and is restricted to low walls only and if the ground conditions has a high water table the water may not be good for the wall durability.
4. Pre-cast crib retaining walls
Crib wall are easy to construct and as it is pre-cast, there is no curing time and constructed with great speed and great heights. The low crib walls are also some time decorative and useful for gardens.
4. Gab-ion walls
Walls that are constructed with a foundation, and gab-ion cages made of gi mesh is filled with rubble stones, and for garden walls the colored stones are filled within the cages and hence it become decorative in nature.
5.Steel wall, sheet piling walls
Sheet pile are driven into the ground to shore up the earth, usually used temporarily for construction of concrete wall or trenches, laying pipes etc, in some instances the sheet piles may be left as a permanent feature.
Wall are constructed using the geo textile materials, the wall is created by wrapping the earth by the edges of the wall in layers and the geo-textiles sheets while holding the edges of the wall, also anchors the earth from slipping.
These wall can get to 20 to 60 feet high or even more if it is staggered, and these wall can be hydro seeding with grass to create a green wall. The geo textile material are anchored into the earth as to anchor the slope from slipping.
7.Green walls ,architectural designs
These walls are decorative in nature but may be used as thermal insulating wall on buildings, where the theme is eco green buildings or eco green homes.