Abstract: To study the frictional resistance characteristics of geogrids and construction residue interface, a series of direct shear tests were conducted on the interface between four different gradations of construction residue and three types of geogrids. The results showed that the relationship between the unit shear displacement and the frictional resistance of the interface between geogrid and construction residue could be expressed by hyperbolic model. The strength of the frictional resistance at the interface increased linearly with the vertical pressure. The structure characteristics of geogrid and the gradation of construction residue determined the frictional resistance characteristics of the grid-residue interface, among which the influence of the tensile modulus of geogrid was the most obvious. The higher the tensile modulus of geogrid was, the greater the quasi friction coefficient and the quasi cohesive strength of the interface were. The quasi friction coefficient was not affected by the gradation of construction residue, but determined by the structure characteristic of geogrid. The quasi cohesive strength was not only affected by the gradation of construction residue, but also related to the structure characteristic of geogrid. For the interface between triax-geogrid and residue, the graded construction residue dominated by medium and fine gravel had the greatest quasi cohesive strength but for the interface between biaxial-geogrid and residue, the graded construction residue dominated by coarse gravel had the greatest quasi cohesive strength. Before and after shearing, the change of the particle gradation of construction residue was a little, so its influence could be ignored.

Key words: construction residue, biaxial-geogrid, triax-geogrid, particle grading, grid structure characteristics, interface friction characteristics