What term describes the disturbance or shifting of soil when it is not in its natural state?

The term that describes the disturbance or shifting of soil when it is not in its natural state is "swell." When soil experiences swell, it refers to the expansion that occurs due to water absorption or other factors that alter its moisture content. This phenomenon is particularly significant in clay soils, which can undergo considerable volume changes when they dry out or become saturated.

Understanding swell is crucial because it can lead to issues such as ground heaving, instability in structures, and alterations in drainage patterns. Contractors need to be aware of swell in order to design foundations and manage drainage effectively to prevent problems associated with soil movement.

The other terms represent different soil conditions and processes. Compression refers to the reduction in volume of soil due to applied pressure, while compaction is the process of densifying soil, reducing voids to increase stability. Stabilization typically involves treatments applied to soil to improve its load-bearing capacity but doesn't specifically refer to the disturbance or shifting of soil.