If the load on a structure placed on a dense sandy soil is doubled, what is expected to happen to the elastic settlement?

The correct understanding regarding elastic settlement is rooted in the principles of elasticity and material behavior under load. When a load applied to a structure is doubled, the elastic settlement—defined as the temporary deformation of a material under load—will also double, assuming the soil behaves elastically.

This relationship is based on Hooke’s Law, which states that stress is directly proportional to strain in elastic materials. Consequently, if the stress on the sandy soil (the load per unit area) is doubled, the resultant elastic deformation (or settlement) will also double, provided the soil remains within its elastic limit and the loading conditions are uniform.

Other options provided do not fundamentally alter the primary relation of load to elastic settlement in this context. While knowledge of sand density or shape and rigidity factor might be important for assessing overall performance and behavior of soil or structure under various conditions, they are not critical to determining the direct relationship between an increase in load and the corresponding elastic settlement in a straightforward manner. The understanding of this direct proportionality is foundational in structural engineering and soil mechanics.