What is [Shrinkage] and [Swelling]

By: Sr vini


Term shrinkage and swelling are basically for the clay soil. in the previous lesson of capillary water, we introduced a word capillary tension, you relate this tension to shrinkage for better understanding.

the main reason for shrinkage is this tension. see the diagram of the shrinkage process.

let see the fig (a) in which soil mass saturated to full level a-a, due to capillary water or any other reason,

Shrinkage and swelling process

assumed temperature increase and some water evaporation take place, due to this evaporation water go to (b-b)

due to this little, small amount of tension come in soil particle, because

we already discuss in capillary water tension,

water stick to the surface of the soil particle, when water level reduced tension produced in water. or obviously compression on the soli particle,

basically, water compresses the soil particle due to tension produced in it. try to visualize for clean understanding.

if further water evaporates the more compression of soil particle come. which give greate shrinkage to soil mass.

but if again water loss case destroyed water tension because no sufficient amount of water present so no more compression produced in between particle, we achieve max shrinkage in the previous case.

that’s all about shrinkage


swelling of soil depends upon the number of factor like increase water content, adsorbed layer, entrapped air, clay minerals, but we consider only increase the water content.
we know shrinkage phenomena if we reverse the shrinkage cycle from max shrinkage stage to no shrinkage by adding water,
expansion of soil particle come and some swelling introduced.

Shrinkage and Swelling Effect

1. The structure faces stress which resting on soil, which has shrinkage and swelling property.

2. swelling case lifting of light structure, which is not good for any structure.

3. Shrinkage and swell soil create the problem on roads maintains.