The soil–water characteristic curve (SWCC) of granular materials is crucial for many emerging engineering applications, such as permeable pavement and methane hydrate extraction. Laboratory determination of the SWCC of granular materials suffers from inaccurate volume readings by the diffused air bubbles in the hanging column and sudden desaturation at small matric suction intervals. Theoretical determination of the SWCC of granular materials also suffers from semi-empirical nature in the prediction from grain size distribution, or from the limitation of assumed cubic packing or face-centred cubic packing with a toroid meniscus water model. In this study, real three-dimensional particle packing was first rendered with the discrete element method using approximation of spheres. Then, the Young–Laplace equation was applied to calculate the volume of toroidal meniscus water between each pair of spheres, which adds to the water content in the pendular regime of the SWCC. Additionally, a digitized image algorithm was used to identify the pore throats and calculate the air entry value and residual matric suction, the connection of which yields a straight line approximating the funicular regime. The SWCC was thus constructed. Comparison with laboratory-measured SWCCs suggested that although reasonable agreement was reached in general for glass beads, residual water content was underestimated, especially for non-spherical granular materials. Several possible reasons were discussed including the existence of patchy water accounting for the major portion of water in the beginning of pendular regime of granular materials, which was also observed in microscopic photographs through a special desaturation experiment.

颗粒材料的土壤-水特征曲线（SWCC）对于许多新兴工程应用（例如渗透性路面和甲烷水合物萃取）至关重要。实验室确定颗粒材料的SWCC时，由于悬挂柱中扩散的气泡以及在较小的基质抽吸间隔下突然脱饱和，导致体积读数不准确。粒状材料SWCC的理论测定在粒度分布预测中还具有半经验性质，或者受环形弯月形水模型假设的立方堆积或面心立方堆积的限制。在这项研究中，首先使用球面近似的离散元素方法绘制了真实的三维粒子堆积。然后，应用Young-Laplace方程来计算每对球体之间的环形弯月面水量，这增加了SWCC摆动状态下的含水量。此外，使用数字化图像算法来识别孔喉，并计算空气进入值和残余基质吸力，两者的连接会产生近似于缆索区域的直线。这样就建立了SWCC。与实验室测得的SWCC的比较表明，尽管玻璃珠一般已达成合理的共识，但残留水含量却被低估了，特别是对于非球形颗粒材料。讨论了几种可能的原因，包括在粒状材料的摆动状态开始时斑水的存在占水的主要部分，