<p>The effectiveness of single and double basal geogrid layers (stiffness equivalent to that of a single layer) as a load transfer platform in encased stone column-supported embankment on lithomargic clay was studied in this paper by using the developed full 3-dimensional (3D) model. Time-dependent 3-dimensional coupled analyses on basal reinforced encased stone column-supported embankments were carried out. In current practice, it is assumed that the performance of geogrid-reinforced encased stone column-supported embankments are similar to geosynthetic reinforced piled embankment systems. Compared to an unreinforced embankment, a 90% reduction in the lateral deformation was obtained when two layers of geogrids (stiffness equivalent to that of a single layer) was provided at the embankment base. When two basal geogrids are provided, the tensile force at the top layer is less than at the bottom. The developed full 3D model was verified with different analytical design methods. The variation of stress reduction ratio with embankment height and tensile force in the basal reinforcement from different analytical methods and 3D numerical model for the encased stone column with a single basal geogrid follows the same trend.</p>