中文摘要：

采用四种格栅（单向、双向和三向）和两种填料（黏土、砂砾石）为试验材料，开展了一系列的大型直剪试验，研究了格栅类型和填料类型、压实度、含水率及剪切速率五个因素对格栅-土界面强度特性的影响规律，并且建立了能够分别对格栅中的横肋-土和纵肋-土界面强度进行单独量化评价的模型，对比分析了同种格栅中纵肋和横肋力学机理以及不同型格栅横肋对抗剪强度贡献的大小。结果表明：（1）对于砂砾石填料，格栅-土界面的似黏聚力从大到小依次为：三向格栅、双向格栅、纵肋较短的单向格栅和纵肋较长的单向格栅，而界面内摩擦角近似相等；（2）填料压实度和剪切速率的增大会分别引起格栅一砂砾石界面似黏聚力和内摩擦角的增大；（3）格栅一砂砾石界面的似黏聚力和内摩擦角都明显大于格栅-黏土界面，而且格栅-黏土界面似黏聚力和内摩擦角随着填料含水率的增大而显著降低；（4）单向格栅的横肋对筋-土界面抗剪强度的贡献要远大于双向和三向格栅的横肋，而且也明显大于其格栅网孔内砂砾石本身的抗剪强度；格栅纵肋-砂砾石界面的抗剪强度能够较好地符合摩擦定律，但其贡献的抗剪强度最小。

英文摘要：

A series of large-scale direct shear tests were conducted to investigate the strength characteristics of geogridsoil interface under different filling, compaction degree, moisture content, geogrid types, and shearing rate. A model, which can quantitatively analyze the contributions of the longitudinal and transverse ribs of geogrid to the shear strength of interface, was presented. The research results indicate that （ 1 ） the interface cohesion follows the sequence, that is, triaxial geogrid 〉 biaxial geogrid 〉 uniaxial geogrid with short longitudinal ribs 〉 uniaxial geogrid with long longitudinal ribs, while their friction angles are approximately equal; （2） the increases of compaction degree of filling and shearing rate may result in the increment of cohesion and friction angle of geogrid-sandy gravel interface, respectively ; （3） for the same geogrid, both cohesion and friction angle of the geogrid-sandy gravel interface are greater than those of geogrid-clay interface, and the strength of geogrid-clay interface is more sensitive to the water content than clay itself; （4） the contribution of transverse ribs of uniaxial geogrid to the shear strength of geogrid-sandy gravel interface are much more than that of other geogrids, and the shear strength of soil-longitudinal rib interface follows the friction law well, but it is the smallest one among all interface shear strengths.