The rupture of buried sewage pipelines constitutes a primary triggering factor of ground collapse. To investigate the phenomenon of ground collapse resulting from buried sewage pipeline breakage and soil particle leakage, numerical simulations employing the discrete element method (DEM) are utilized. The study focuses on examining the ground collapse mechanisms in both dry and water-rich sand stratum scenarios. A positive correlation is identified between the particle loss rate (PLR) and the magnitude of ground collapse, and a microscopic analysis of the mechanism of particle loss is undertaken to visualize the soil arching process. The entire collapse process shows that the formation and destruction of soil arching are clearly accompanied by the particle loss phenomena. Additionally, the computational fluid dynamics (CFD) module is incorporated into the DEM to investigate the collapse of water-rich sand stratum. Parametric studies involving the burial depth of the pipeline, water pressure, the defect radius of the pipeline breakage, and the defect shapes are comprehensively conducted. It is found that the water pressure is the primary factor influencing the PLR, which progressively increases with higher water pressure, larger radius of defect, and shallower burial depth.