Abstract: It is of great engineering significance to study the shear characteristics of the interface between structure and soil for the axial capacity and stability of the piled foundation. In this paper, the interface shear tests between steel and low liquid limit clay are performed by using the improved direct shear instrument, considering the two factors of the soil water content and the compression time. The relationship between the shear stress and the shear displacement, the shear strength index is analyzed respectively. The results show that the relationship between the shear stress and the shear displacement of the interface can be expressed by a hyperbolic model. The test peak shear stress and the model peak shear stress increase with the normal stress and the compression time and increase first and then decrease with the water content. The failure ratio ranges from 0.851 to 0.960, and the initial shear stiffness range from 19.96 to 131.58. The cohesion and the friction angle of the interface increase first and then decrease with the water content and reach the maximum near the optimal water content. The cohesion and the friction angle of interface are positively proportional to the compression time.

Key words: Steel, Low Liquid Limit Clay, Shear Stress, Water Content, Compression Time, Shear Strength Index