What does immediate (elastic) settlement primarily result from?

Immediate (elastic) settlement primarily results from the elastic deformation of the soil. This type of settlement occurs almost instantaneously upon the application of a load, such as when a building is constructed on a foundation. When the load is applied, the soil particles rearrange slightly, but this movement is primarily temporary and reversible; the soil acts like a spring. The deformation is a result of the soil's immediate response to the increase in stress due to the new load, which leads to a corresponding change in volume or displacement.

Elastic settlement is distinct from other forms of settlement, such as consolidation settlement, which involves changes in water content and pore pressure over time. This instantaneous response means that the elastic settlement is typically calculable using soil modulus values, reflecting the soil's stiffness under load conditions. The significance of recognizing elastic settlement lies in ensuring that foundation design accounts for these immediate changes in structure due to the loading conditions.