<p>Saline sabkha soils pose a major challenge for geotechnical engineering because of their low bearing capacity and high settlement potential. The purpose of this research was to evaluate the behavior of stabilized sabkha soil under axial stress after geopolymer treatment utilizing the mix and compact method. A comprehensive numerical analysis, validated by experimental results, was conducted to study the load–displacement behavior of sabkha soil in its natural and treated states. A parametric study using the finite element method was performed to examine the effects of the thickness and diameter of the geopolymer-treated soil layer on the ultimate bearing capacity (UBC). Response surface methodology and ANOVA were employed to develop and evaluate a predictive model for UBC as a function of the dimensionless ratios H_m/D_f and D_m/D_f. The results revealed that the geopolymer treatment significantly enhanced the load-bearing capacity of sabkha soil by increasing the thickness and diameter of the treated soil layer. However, a higher ratio of D_m/D_f than 2 adversely affected soil performance when the H_m/D_f ratio was less than 0.6. The study also demonstrated that geopolymer is a novel and environmentally friendly technique for stabilizing sabkha soils, as it utilizes waste materials (fly ash and mine tailings).</p>