Abstract: The interfacial properties between geo-grid and soil are important for representing the reinforcement of the geo-grid and are of great influences on the stability and the deformation-failure characteristics of geo-grid structures. At present, various specifications and standards fail to consider the influences of mesh sizes on the parameters selection of geo-grid soil interface, leading to artificial selection of geo-grid in practical engineering. In this paper, the numerical model studies the characters of geo-grid interface through comparative analysis between indoor experiments and numerical methods. The results show that the mesh size of geo-gird has dramatic influences on the characteristics of geo-grid interface. Through analyzing the principles of the influences of different mesh sizes on the interface characters, it shows that the friction effects of geo-grid interface should be excluded from the comprehensive friction on the interface to explore the effects of reinforcement more directly. Meanwhile, the reasonable mesh size of geo-grid should ensure that the effective contact between geo-grid and soil should be one-third of the whole interface.

Key words: geo-grid, interface character, reinforced structure, reasonable mesh size, numerical method