<p>With the development of vacuum preloading techniques, the understanding of consolidation-induced clogging has become increasingly comprehensive. Clogging during vacuum preloading can be primarily categorized into three types: drainage plate clogging, particle migration-induced clogging, and uneven consolidation-induced clogging. The application of graded vacuum pressure has been shown to promote soil consolidation and drainage; however, the mechanisms underlying its mitigation of clogging remain largely described qualitatively, lacking detailed microscopic and simulation-based verification. The coupled scheme of the lattice Boltzmann method (LBM) and the discrete element method (DEM), capable of accurately capturing interactions between particles and between particles and fluid, has been widely applied in particulate flow studies. In this study, vacuum preloading tests under different graded loading schemes were conducted and coupled with LBM–DEM simulations to provide a more in-depth investigation into the mechanisms by which graded pressurization alleviates clogging. Both experimental and numerical results indicate that applying graded pressure can partially mitigate soil clogging, and the magnitude of the pressure gradient between consecutive stages significantly affects the final consolidation performance of the soil.</p>