Comparison with shear strength of the expansive soil under two different conditions

The direct shear test and moistening shear test results are compared in this paper by using direct shear apparatus for the expansive soil in Ankang.The experiment and comparison results show that the ultimate shear stress,cohesion and angle of internal friction decrease along with the broadening of water content in the expansive soil.The shear stress value of samples in moistening shear test is much smaller than in direct shear test along with the increase of water content under the same consolidation pressure,the smaller the water content,the less the disparity of ultimate shear stress value for two kinds of tests;the shear strength values between the direct shear test and the moistening shear test are greatly different.Cohesion and angle of internal friction decrease along with the broadening of water content and the better linear relation exists in the moistening process.