<p>Floating stiffened deep mixing (SDM) piles are sometimes employed to enhance embankments in areas where the subsoil comprises thick and soft clay. This study conducted three sets of model tests to comparatively analyze the performance of embankments supported by floating and end-bearing SDM piles. Three-dimensional (3-D) numerical modeling was performed to analyze the progressive failure of embankments reinforced with SDM piles. Results demonstrate that the floating SDM pile had a similar enhancement in embankment stability, but the end-bearing piles were more effective in restraining the embankment displacements and ground heaving before embankment failure. The failure modes of the SDM piles were dependent on the positions under the embankment base, and the end-bearing and floating piles had different failure modes. As the surcharge increased, the SDM pile underwent progressive failure. The piles beneath the crest of the embankment failed under compression, followed by a sequential failure of the piles under the slope from the foot to the shoulder due to bending.</p>