中文摘要：

为研究筋土界面特性及节点突起对格栅加筋性能的影响，采用三维离散元方法，通过副颗粒的引入从构造上对节点处突起进行了模拟，并对含节点突起的三向土工格栅拉拔过程进行了仿真分析，系统研究了筋一土界面剪胀效应，揭示了宏观强度发展与细观组构演化的内在关联，明确了节点突起对格栅工作性能的改善。研究结果表明，傅里叶系数曲线与拉拔力曲线偏离较大，综合考虑法向接触力幅值与各向异性程度的组构演化系数更能准确反映宏观强度的发展；节点突起调整了纵肋内力分布，允许筋一土间发生较大程度的相对位移，更有助于材料性能的充分发挥。研究成果可为从细观角度优化格栅加筋性能提供参考。

英文摘要：

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.