An apparatus capable of direct shear type and simple shear type testing of interfaces between soil and structural materials is developed. A series of monotonic and cyclic tests are conducted at the interfaces between dry sand and a rough surface under constant normal stress conditions with both methods. The test results indicate that the peak and residual shear strengths obtained from direct shear and simple shear are approximately the same. However, the simple shear box permits separate measurements of shear deformation of the sand mass and also sliding at the contact surface
