Soil-water characteristics curve (SWCC) describes mainly the relationship of suction and volumetric water content of nonsaturated soil; it is very important to research the fundamental properties of SWCC. The relationship between SWCC and nonsaturated seepage curve has been studied based on theory and experiment. the features of SWCC and of nonsaturated seepage curve are studied by natural proportional rule; then the characteristics among SWCC and its differential curve

nonsaturated seepage curve

grain distribution curve are researched in physics and mechanics; the scope of constant index of SWCC and of nonsaturated seepage function is given; and their relationship is described. The experimental results show that the SWCC is influenced by lots of factors

such as: material compositions

plastic index

porous structure and stress state. The study of SWCC is very important to engineering construction.