Settlement Free Construction
Effective stress is a measure of the stress on the soil skeleton (the collection of soil particles in contact with each other) and determines the ability of soil to resist settlement and shear stress. The principle of equilibrium (see diagram below), states that when soils are excavated and replaced with foam concrete of a lighter density, the combined weight of the foam concrete and the new construction should be designed to be less than, or equal to the weight of the removed soil.
In conforming to this principle the effective stress of the underlying soil remains unchanged from that existing prior to excavation and thus settlement of the construction is prevented.
Principle of Equilibrium
