Definition and exploration for effective stress and related conception in unsaturated soil

The effective stress for unsaturated soils was reviewed,and the surface tension,matrix potential,absorbed suction,intrinsic structure suction and variable structure suction were defined and discriminated rigorously.Then a new concept and the unified formula of effective stress for saturated soils as well as for unsaturated soils were proposed.The effective stress formula was also analyzed by use of an actual case.