Bottom-initiated radial cracking is a special phenomenon for soil as it is subjected to desiccation. This study aims to simulate the initiation and propagation of radial cracks in soil using both experimental and discrete-element method (DEM) approaches. Under controlled conditions of constant temperature and humidity, a laboratory desiccation test of clayey soil samples with bottom-constrained boundary conditions was carried out to illustrate the soil bottom-initiated radial desiccation cracking behavior. The evaporation characteristics as well as the development of radial cracking initiating from the subsoil were captured. To simulate this phenomenon, a desiccation model based on discrete-element method was used in DEM. Based on the laboratory testing results, appropriate parameters are selected for the numerical simulations. The DEM approach was calibrated by reproducing the experimental results of radial desiccation cracking. Subsequently, the initiation and propagation mechanisms of this typical soil cracking phenomenon was analyzed and discussed. With the constraint of the bottom boundary, the initiation of radial desiccation cracking was associated with the arched distribution of inter-particle tensile force in the soil samples. The propagation direction of the cracks was perpendicular to the inter-particle tensile forces. Finally, the effects of basal friction, evaporation gradient and shrinkage parameter on the bottom-initiated radial cracks in the simulation were analyzed. The size of the bottom particles and interface bonding factor played a significant role in the effect of basal friction. Compared with the samples under uniform water loss conditions, the bottom shrinkage rate was relatively low for the sample under a gradient water loss. In addition, an increase in the shrinkage parameter of the soil particles led to a greater extent of crack propagation.

底部引发的径向开裂是土壤干燥时的一种特殊现象。本研究旨在使用实验和离散元方法 (DEM) 方法模拟土壤中径向裂纹的萌生和扩展。在恒温恒湿控制条件下，对具有底部约束边界条件的粘质土样进行室内干燥试验，以阐明土体底部引发的径向干燥开裂行为。捕获了蒸发特性以及从底土开始的径向裂纹的发展。为了模拟这种现象，在 DEM 中使用了基于离散元方法的干燥模型。根据实验室测试结果，选择合适的参数进行数值模拟。 DEM 方法通过再现径向干燥裂纹的实验结果进行校准。随后，对这种典型土体开裂现象的引发和扩展机制进行了分析和讨论。在底部边界的约束下，径向干燥开裂的发生与土样中颗粒间拉力的拱形分布有关。裂纹的扩展方向垂直于颗粒间张力。最后，分析了模拟中基础摩擦力、蒸发梯度和收缩参数对底部引发的径向裂纹的影响。底部颗粒的尺寸和界面结合因子对底部摩擦的效果起着显着的作用。与均匀失水条件下的样品相比，梯度失水条件下的样品底部收缩率相对较低。此外，土颗粒收缩参数的增加导致裂纹扩展程度更大。