What is the major settling component in sandy soils?

Immediate settlement is the major component in sandy soils due to the nature of their granular structure. When load is applied to sandy soils, the particles rearrange and denser packing occurs almost instantaneously. This settling happens quickly as the voids between the grains are filled, leading to an immediate decrease in volume under stress.

In contrast, primary consolidation refers to the deformation of saturated clay soils as pore water is expelled from the soil matrix under stress. Elastic settlement pertains to the immediate elastic response of any soil type when load is applied, but in sandy soils, the significant volume change occurs due to the reconfiguration of particles rather than elastic deformation. Secondary consolidation, on the other hand, involves time-dependent adjustments in the structure of saturated soils, particularly clays, as moisture redistribution occurs after primary consolidation is complete.

Therefore, immediate settlement is the predominant factor when considering how sandy soils respond to loading.