<p>Exfiltration of a buried defective pipe is prone to incur an unseen cavity in the strata around its opening and then causes a sudden ground collapse or a sinkhole accident, inherently related to the cavity properties and pipe structure. Unfortunately, few researches in the literature have contributed to this issue. In this study, a two-dimensional (2D) discrete-element method (DEM) validated by experimental model tests was employed to investigate the cavity collapse-induced ground subsidence and the stress redistributions of overburdening strata under the exfiltration flow of the buried defective pipe. Comprehensive parametric studies were conducted to examine the effects of cavity size, burial depth, and pipe structure. Based on the numerical results, theoretical analyses were performed to interpret the distributions of cavity collapse-induced ground movements and stress changes. It was revealed that ground subsidence due to the cavity collapse could be estimated using a modified Gaussian function; the maximum magnitude of ground subsidence increased as the cavity size increased and burial depth of the cavity decreased. Both the numerical and experimental results demonstrated the existence of stress arching over a destabilized cavity, which was capable of alleviating ground subsidence; the envelope curve of stress arching could be evaluated in combination of natural equilibrium arch theory and soil stress distributions. Moreover, the evolutions of ground collapse and stress arching were affected remarkably by the pipe structure and its relative location to the formed cavity.</p>