In order to study the influence of water content on the strength and deformation of slip soil

select a large scale landslide’s slip soil is selected to conduct consolidated-drained triaxial shear test with different initial saturations. Study the volume strain of unsaturated soils is studied by adopting a new gas and water converting device. The results show that the water content has great influences on the strength of slip soil; the higher the initial saturation is

the lower the strength value is. Strength parameter c with saturation is the ladder-like drop relationship; and linear relation could be established between strength parameters ? and initial saturation. The higher water content is

the smaller the soil sample’s volume deformation is; and the parameters of Duncan-Chang model such as K

Kb

and G are affected largely by water content; and then the linear formula could be established between the initial saturation and these parameters of Duncan-Chang model. But other parameters of Duncan-Chang model such as n

m

F

Rf

and D

which are little affected by water content

have little difference value under different initial saturations

so the averages are made as the model parameters under different saturations.