Consolidation settlement may be defined as
” The type of settlement in which the increase in vertical effective stress causes the individual particles of the soil to rearrange into a tighter packing, is known as consolidation settlement.”
It is also known as Primary consolidation settlement.
When the soil is subjected to increase in vertical effective stress than it experience some consolidation, and this is usually the most important source of settlement.
This process causes a decrease in volume of voids. If the soil is 100% saturated then the reduction in volume of voids can occur only if some of the water squeezed out of the soil.