Shrinkage and Swelling of Soils

The soil shrinkage is defined as the specific volume change of soil relative to its water content and is mainly due to clay swelling properties. Shrinkage is due to the volume change of the soil plasma and to some extent of the structural porosity with water content. Shrink / swell potential is the relative change in volume to be expected with changes in moisture content, that is, the extent to which the soil shrinks as it dries out or swells when it gets wet. Extent of shrinking and swelling is influenced by the amount and kind of clay in the soil.