• Control of the volume change tendency. Suppose the void ratio is high (loose soils). Under loading, voids in the soil skeleton tend to decrease (shrinkage), increasing the contact between adjacent particles and modifying the soil
effective stress. The opposite situation, i. e. when the void ratio is relatively small (dense soils), indicates that the volume of the soil is vulnerable to increase (swelling) under unloading – the
smectite (
montmorillonite,
bentonite) partially dry
clay particles present in an unsaturated soil can swell due to their
hydration after contact with water (when the saturated/unsaturated conditions fluctuate in a soil). • Control of the fluid
hydraulic conductivity (ability of water movement through the soil). Loose soils show a high hydraulic conductivity, while dense soils are less
permeable. • Particle movement. Small, unbound particles can move relatively quickly through the larger open voids in loose soil. In contrast, in dense soil, finer particles cannot freely pass the smaller
pores, which leads to the clogging of the
porosity. == See also ==