Abstract: Liquid index is one of the most important indices of clayey soils. It describes the consistency of the cohesive soils and it is widely used to empirically assess the bearing capacity of the cohesive strata. During the geotechnical investigation, it is often noted that the liquid index of soft clay obtained from the remolded state appears to be higher than that obtained from the undisturbed soils samples. After the microstructure studies, it is concluded that three different waters exist in the cohesive soil fabric: strong bonded water, weak bonded water and free water. The consistency is not determined by all of the waters around the clay particles, but is determined by the statement of water connecting the clay particles. The thickness of water membrane connecting the clay particles at the insitu condition is thinner than those at remolded condition. So the in situ soils are stiffer than those remolded soils with. Since the remolded soil is used in laboratory test to obtain liquid limit and plastic limit, liquid index is more suitable to assess the statement of remolded soil other than the in situ soils.

Key words: Soft Cohesive Soils, Liquid Index, Soil Microstructure, Bonded water, Remolded Soils.