How do clay particles behave when water is removed from an expansive soil?

When water is removed from expansive soils, the behavior of clay particles is crucial to understanding soil properties and stability. As water is withdrawn, the moisture content of the soil decreases, leading to a reduction in the volume of the soil. This phenomenon occurs because clay particles are hygroscopic, meaning they absorb and retain water between their layers.

As the water evaporates or is drained, the attraction between the clay particles increases, causing them to come closer together. This process is known as shrinkage, which can significantly affect the soil structure. The result is a decrease in volume, often leading to cracking and other forms of soil distress.

Consequently, the correct response demonstrates an essential characteristic of expansive soils: the tendency for the clay particles to lessen the distance between one another when the water content is reduced, impacting overall soil behavior and engineering applications. Understanding this behavior is vital for professionals dealing with soil mechanics, construction, and land management.