Large-Strain Consolidation of Slurry Induced by PHDs Incorporating the Development Process of the Elliptical Clogged Zone and Non-Darcian Flow

Abstract The prefabricated horizontal drains (PHDs) combined with vacuum preloading (VP) method has become a widely used technique for dredged slurry treatment. Experimental studies have shown that clogging effect occurs during vacuum preloading consolidation, and seepage in soft soils deviates from Darcy’s law. To accurately predict the consolidation behavior of dredged slurry induced by PHDs-VP, this study proposes a large-strain consolidation model incorporating the development process of the elliptical clogged zone and Hansbo’s non-Darcian flow model. The governing equations are established, and numerical solutions are obtained utilizing the alternating direction implicit finite-element method. The correctness and reliability of the proposed model are validated through comparison with well-established consolidation theory, laboratory test results, and field measurements. Parametric analyses demonstrate that clogging effect and non-Darcian flow both retard consolidation, with the impact of clogging effect being particularly significant. The optimal PHD layout ratio is obtained for different slurry layer thicknesses and is found to decrease as the slurry layer thickness increases. Neglecting the clogging effect leads to a substantial underestimation of the optimal layout ratio, whereas neglecting the non-Darcian flow effect causes only a slight additional reduction.