ABSTRACT
In Japan, shear tests directly performed on the slip surface of landslide are seldom executed. Primarily because it is too difficult to match the shear surface and the undisturbed slip surface with the traditional direct shear apparatus. To solve this authors have been pursuing the development of a reversible direct shear box apparatus that would be able to adjust the position of slip surface to coincide with the shear surface of the apparatus since 1994. This paper describes both the principles of Slip Surface Direct Shear box apparatus (SSDS) and its application to the slip surface. From the test results, a typical stress path on the slip surface is obtained. Comparing ring shear tests with SSDS tests, it is intriguing to find that if the sample prepared for a ring shear test has the same clay content as the slip surface clay, both results show the same strength parameter.
