The accurate determination of the interface shear strength is essential in the design of geosynthetic-reinforced soil structures. The particle geometries of three types of soil materials and a spherical granular medium are imaged and quantified using binary image-based methods and described in terms of regularity. Cyclic direct shear tests are conducted to investigate the effects of particle regularity on the interface shear strength, stress–displacement relationship, shear stiffness, and damping ratio. The results reveal that the interface shear strength and deformation strongly depend on particle regularity. The vertical displacement ratio is found to increase with particle regularity under the same cycle number. The interface stiffness is observed to increase with the cycle number for particle regularities of 0.453, 0.565, and 0.672 but decreases with the cycle number for a particle regularity of 0.971. For a given regularity, the trend of damping ratio with the increasing cycle number is contrary to the that of shear stiffness. Finally, it is observed that the cyclic friction angle decreases with increasing particle regularity, the relationship of which is determined using linear regression. Thus, the systematic quantification of particle shape characteristics can lead to a better understanding of soil–geogrid interface behaviour.

界面抗剪强度的准确测定对于土工合成材料加筋土结构的设计至关重要。使用基于二进制图像的方法对三种土壤材料和球形颗粒介质的颗粒几何形状进行成像和量化，并根据规律进行描述。进行循环直接剪切试验以研究粒子规则对界面剪切强度、应力-位移关系、剪切刚度和阻尼比的影响。结果表明，界面剪切强度和变形强烈依赖于颗粒的规则性。发现在相同循环数下，垂直位移比随着颗粒规律性增加。观察到界面刚度随着粒子规律性为 0.453、0.565 和 0 的循环数而增加。672，但随着粒子规律性为 0.971 的循环数而减少。对于给定的规律，阻尼比随循环次数增加的趋势与剪切刚度的趋势相反。最后，观察到循环摩擦角随着颗粒规则性的增加而减小，其关系使用线性回归确定。因此，颗粒形状特征的系统量化可以更好地理解土壤-土工格栅界面行为。其关系使用线性回归确定。因此，颗粒形状特征的系统量化可以更好地理解土壤-土工格栅界面行为。其关系使用线性回归确定。因此，颗粒形状特征的系统量化可以更好地理解土壤-土工格栅界面行为。