What causes elastic settlement of the ground due to a surface load?

Elastic settlement occurs when a surface load is applied to the ground, causing the soil to deform while maintaining the same volume of water within its pore spaces. This type of settlement is characterized by immediate and recoverable deformation due to the compacting of soil particles in response to the applied load.

When a load is applied, the stress at the soil surface increases, leading to deformation as the soil adjusts to the new load without any accompanying changes in water content. This is important because, in elastic settlement, the soil skeleton itself bears the load, and the water remains within the pores, effectively causing the soil structure to compress elastically.

This contrasts with other types of soil behavior, such as consolidation, which involves a change in water content as excess pore water pressures dissipate and water is expelled from the soil. The instantaneous nature of elastic settlement makes it critical in foundation design, as it can lead to immediate deflections after load application, even before any significant consolidation takes place.

Understanding this process is essential for civil engineers when designing structures and predicting ground behavior under loading conditions.