Retaining Walls and Soil Foundations
When constructing a new building, it is not possible to just simply start building on a plot of land. There is a lot of foundation preparation which needs to be carried out in the initial stages of a construction project. One of most important factor when carrying out foundation or retaining wall work is to ascertain what type of soil you are building on.
Soil is essentially the geological erosion or rocks and is made up of solid particles and then voids. These voids – or spaces – can be filled with water or air or a combination of the two. In the UK, most soils do not contain any air once they are one metre below the surface. This is known as saturated soil.
There are many types of soil but for building purposes soil is generally split into two categories; sandy silt and boulder clay. Soils which are made up of 25% clay particles have different properties to coarser soils and it sticks together. This type of soil also swells and contracts depending on the water content. The process of water being squeezed out of this soil is known as consolidation and is one of the main causes of building settlement. Buildings can still be going through the settlement process decades after being built.
Different soil foundations require different methods of stabilisation which is why it is important for contractors to carry out thorough site investigations and decide whether a retaining wall or other foundation works are appropriate.