Hidden soil caves pose a serious threat to the stability and safety of subgrades. In this study, using the two-dimensional particle flow discrete element code, a total of eight subgrade models with circular soil caves of different dimensions, depths, and locations were established. Under self-weight and superimposed loading, the deformation characteristics of fill subgrade models, such as the evolution of displacement field and crack development process, were analyzed. The results show that under the self-weight, after the fill subgrade model of soil caves with diameters of 2 m, 4 m, 6 m, and 8 m is stable, the overlying soil layer of the soil cave corresponds to the transformation of slag falling, block falling, collapse and rapid collapse, respectively. The larger the dimension of the soil cave, the larger the number of cracks and damage areas, and the more prone the fill subgrade is to collapse. The superimposed load makes the fill subgrade compress from shallow to deep, significantly increasing the overall subgrade deformation, the number of cracks, and the development range. The evolution of the displacement field and crack propagation of the fill subgrade are also controlled by the buried depth and location of the soil cave. Whether the fill subgrade collapses is comprehensively controlled by the dimension and buried depth of the soil cave, the mechanical parameters of the soil layer, the load, and its scope of action. Thus, a comprehensive criterion of cylindrical collapse of the soil layer above the soil cave is constructed.

来源平台：ENGINEERING FAILURE ANALYSIS