Expansive soils contain minerals, such as smectite clays, that are prone to absorb copious amounts of moisture. When they take on water, they increase in volume. The more water they absorb, the more their volume increases.
What Causes Volume Change in Expansive Soil?
An expansive soil is a type of soil that can swell or shrink in volume depending on the amount of moisture present. This can cause serious problems for structures built on or near these soils, since the changes in volume can damage the foundations and walls.
There are many factors that can contribute to the formation of expansive soils, but the most common is the presence of clay.
Clay particles are very small and have a large surface area, which allows them to absorb water easily. When the clay particles absorb water, they expand in volume, and this can cause the soil to swell.
The amount of clay present in the soil is not the only factor that can affect its expansiveness. The type of clay present can also have an impact.
For example, montmorillonite clay is known to be more expansive than kaolinite clay. The amount of water present in the soil is also a major factor.
If the soil is very dry, it will shrink in volume. However, if the soil is saturated with water, it will expand. In some cases, the changes in volume can be caused by changes in the surrounding environment.
For example, if the soil is exposed to a sudden change in temperature, it can cause the soil to expand or contract