During the drying process of a soil under constant total stresses

the increase of soil suction will induce the drainage of pore-water and the shrinkage of soil pore-structure. For a soil at a particular state

the microstructure determines its void ratio; and the soil suction determines the water content. During the drying process

if the pores are assumed not to shrink until the pore-water drains

then soil suction provides a bridge between the soil microstructure and soil draining behavior represented by the soil-water characteristic curve and the soil shrinkage curve: (1) the envelope of the cumulative pore volume curves is the soil-water characteristic curve; (2) the shrinkage curve is found to locate in a narrow range which can be determined using the cumulative pore volume curve.