The mechanical properties of soil-reinforcement interaction are of utmost importance for the design and stability analysis of reinforced soil structures. Using large-multifunctional interface shear apparatus

a series of horizontal cyclic shear tests are carried out between geogrid and standard sand. The mechanical behavior of geogrid-soil interface is recorded and analyzed. Then the influences of the characteristics of horizontal cyclic load on the interface shear strength and vertical displacement are studied. In the end

the mechanism of soil-reinforcement interaction under horizontal cyclic load is investigated. The results of this research indicate that the curves of shear force and displacement merge into one curve gradually with the increase of shear cycles; the change of shear stress summit is not obvious; the interface shear modulus increases with the cyclic load and reaches stable. The influence of the amplitude and velocity of shear displacement on shear strength is not evident; but the amplitude and velocity of shear displacement have significant effects on the vertical displacement of the samples during horizontal cyclic shear tests. In the process of horizontal cyclic shear tests

the sample takes obvious vertical displacement. The reinforcement has effective confinement to the vertical deformation of test samples.