为研究颗粒粒径对格栅-粗粒土界面单调直剪和循环剪切特性的影响，利用大型直剪仪进行了一系列室内大型单调直剪试验、循环直剪试验和循环后单调直剪试验，并将单调直剪试验与循环后单调直剪试验的结果进行了对比分析，研究了循环剪切应力历史对界面直剪强度特性的影响。结果表明：单调直剪试验中，随着粗粒土粒径的增加，界面似黏聚力和内摩擦角增加；循环剪切中界面抗剪强度发生硬化，同一循环位移幅值下颗粒粒径越小，界面在循环剪切过程中的硬化速度越快；遭受循环剪切后界面残余应力比降低，峰值似黏聚力显著增长。

To investigate the influence of soil particle size on geogrid-coarse soil interface cyclic and post-cyclic shear strength behavior, a series of large scale direct shear tests, cyclic shear tests and post-cyclic direct shear tests is conducted through a large-scale direct shear device. The influence of cyclic shear history on interface shear behavior is studied according to the comparison and analysis of the results obtained from direct shear tests and post-cyclic direct shear tests. The results show that, in direct shear tests, the interface apparent cohesion and friction angle both increase with soil particle size increase. In cyclic shear tests, the shear strength tends to harden under different particle sizes; for the same amplitude of cyclic shear displacement, the smaller the particle size is, the faster the hardening rate of interface is. After subjected to cyclic shear, the ratio between residual shear stress and peak shear stress of interface decreases; and the peak apparent shear stress increases insignificantly.