Abstract: Effects of the interface characteristics between geogrid and soil and joint protuberance on the geogrid performance are investigated by three-dimensional discrete element method. To simulate the protuberant joint, minor particles are introduced; so that the pull-out test of triaxial geogrid with joint protuberance can be modeled thoroughly. Through analyzing the shear dilatancy effect of the interface between geogrid and soil, the inherent relationship between strength (macroscopic) and fabric anisotropy (microscopic) is revealed; meanwhile, the improvement of geogrid performance attributed to the protuberant joint is also proved. Numerical results show that larger deviation can be found between the curves of Fourier coefficient and pull-out force. In terms of the development of strength (macroscopic), its accuracy can be obtained via considering normal contact force and fabric evolution coefficient which reflects the degree of anisotropy. Moreover, with the existence of protuberant joint, the internal force distribution of longitudinal rib can be homogenized; larger relative displacement between geogrid and soil will be allowed; and the material properties could be well performed. The research results can provide reference for optimizing the geogrid reinforcement performance microscopically.

Key words: joint protuberance, fabric anisotropy, pull-out test, discrete element method