Abstract: In geopolymer reinforced soil structure, the behavior between the soil and geopolymer is very important to inner stabilization of reinforced soil structure, so the index between the soil and geopolymer is a crucial index. In this paper, systematic directtests and pullout tests were carried out between high liquid limit clay and two kinds of geopolymers. Based on the test result, stress-strain relationship is studied. Some useful conclusions and opinions which can be used to supervise the research and design are also presented. That is, the shear stress between the clay and the geopolymer increases with the normal stress increase, but the increase is not unlimited, and the increase ratio of shear stress will decreases. So the high-point of shear stress exists between clay and geopolymer. Due to sample preparation for pullout test, the scraggy interface between clay and geopolymer will generate anchor effect which leads to the friction coefficient and cohesion gained from pullout test more larger than that gained from direct shear test. But in practical engineering, the pullout test can better reflect the truth.

Key words: interface, behavior, high liquid limit clay, direct shear test, pullout test, anchor effect