<p>Sand Compaction Piles (SCPs) are widely used to improve the performance of soft soils supporting heavy structural loads, e.g., increase in bearing capacity and settlement reduction. This study introduces a robust investigation into the performance of SCP-reinforced ground, integrating an analytical validation using an advanced three-dimensional Lagrangian numerical modeling. Current modeling techniques, such as the composite cell method, using a finite element framework, are shown to significantly underestimate field-observed displacements due to oversimplified boundary assumptions and the neglect of soil enhancement effects post-installation. To overcome these limitations, a fully Lagrangian finite difference model is developed using FLAC3D and calibrated against the Greenwood analytical solution. Agreement is demonstrated up to the moderate loading range, while settlement deviation at higher stress levels is discussed in terms of constitutive idealizations and numerical sensitivity. This model captures the complex interaction mechanisms between SCPs and the surrounding soil, revealing a substantial increase in stiffness and a marked reduction in settlement - up to 60% - after SCPs installation and applied load. The simulations explore the influence of key parameters, including pile length, sand friction angle, improvement area ratio, and pile configuration beneath both isolated footings and large rigid rafts. Results underscore the importance of accurately modeling lateral deformation and stress distribution, particularly in distinguishing the behavior of floating versus end-bearing SCPs. By benchmarking the 3D Lagrangian finite-difference model against Greenwood’s solution within the applicable stress range, the paper provides mechanistic insights into stress transfer and deformation in SCP-reinforced ground and proposes design-oriented trends and thresholds for preliminary SCP layout selection under short-term monotonic loading.</p>