Abstract: Aiming at studying the evolution of the microstructure in the interface and quantitatively assessing the extent that friction coefficient influences the reinforcement performance, a three-dimensional discrete element model is established; and the strengthened node of triaxial geogrid is factually simulated by jointing the surrounding particles with the assistance of “clump” logic. The mechanical responses of reinforced soil and geogrid under pull-out loading are analyzed. Compared with the experimental and theoretical results of previous reports, the accuracy of the model used in this study is verified. Meanwhile, the variation law of meso-structure parameters, such as local void ratio and coordinate number are obtained. Afterwards, parametric study on friction coefficient is carried out, and it can be found that the apparent cohesion is positively related to the friction coefficient. However, the internal friction angle cannot increase continuously when friction coefficient reaches a certain value. The statistical results demonstrate that the improvement of macroscopic interface strength could be reasonably attributed to the optimization of microscopic fabric. The presented methods in analyzing soil-geogrid interface and achievements in this paper could provide a new understanding for mechanism analysis of reinforced earth structure.

Key words: triaxial geogrid, pull-out test, friction coefficient, discrete element method