Study on shear strength of unsaturated soils based on the saturated soils

The research on shear strength of the unsaturated soils become hot topics and difficult topics in recent years. Because of some defaults on the current calculation formula in international they can not be used into the practical engineers. It has tended to mature and perfect in the research of saturated soil shear strength theory in the world. It has became one of the feasible methods to use the theory of shear strength of saturated soil into the unsaturated soil and the research in these area has been carry out gradually. Considering the distinguishes difference in shear strength between unsaturated soil and saturated soil is water content. In this paper, the shear strength parameters of unsaturated soils has been divided into two parts, one is the saturated soil shear strength parameters and the other is water content influence on the shear strength parameters of unsaturated soiled. And this paper has studied the water content influence on the unsaturated soil parameters separately and put forward calculation formula. We used other experts tested numbers to prove that the formula which we put forward is correct. The formula which we put forward has some values in practices.