What property is associated with soils that undergo significant volume changes?

Soils that undergo significant volume changes, particularly shrinkage and swelling, are typically associated with a high plasticity index. The plasticity index is a measure of the plasticity of a soil, which reflects its ability to change volume with changes in moisture content. A plasticity index above 40 indicates that the soil has high plasticity and is likely to exhibit significant volume changes when wet or dry.

For example, clay-rich soils like expansive clays have high plasticity. When these soils are saturated with water, they swell significantly, and when they dry out, they shrink. This behavior can lead to serious engineering challenges, such as foundation movement or cracking in structures if not properly accounted for in design.

In contrast, other options relate to certain characteristics of the soil that do not inherently indicate volume change behavior. A liquid limit below 10% suggests that the soil is non-plastic and relatively stable, while a moisture content below 10% does not imply expansive behavior. Similarly, organic content below 10% does not directly correlate to the volume change properties of the soil. Thus, the property associated with significant volume changes is accurately represented by a plasticity index above 40.