Abstract:The direct shearing test on characteristics of interfaces were conducted on the DSR-1 computerized high stress direct/post shearing system for standard sand,building sand,silt and clay interfaced with concrete,smooth metals and rough metals,respectively. The results show that the relationships between the normal stress and the peak shear strength,as well as between the normal stress and the residual shear strength are in accord well with Mohr-Column strength criterion under high stress,and the base influence is weak on the peak shear strength criterion of standard sand,but strong on the residual one. The residual shear strength criterion of concrete-base is related to the value of normal stress. When the normal stress is less than 2.44 MPa,shear failure takes place in standard sand,and when the normal stress is more than 2.44 MPa,the failure takes place on the interfaces. The shear failure of other base always happens in the interface. The curve of volumetric strain-shearing displacement in the shearing course of standard sand shows that when normal stress is less than 4 MPa,the curve appears as yield platform,and when it is more than 4 MPa,the curve presents hardening phenomenon according with the hyperbolic model and the corresponding volume change is contractive. The variance and direct-viewing analysis of the test data show that the normal stress is the main factor,soil property is the second one,roughness of base is the third one,and shearing rate is the fourth one to affect residual shear strength and initial shear stiffness.