Sandy soil liquefaction poses a significant risk to shallow foundation structures. Shallow foundations subject to significant settlement, lateral displacement, and overturning are susceptible to earthquake-induced soil liquefaction. This study investigates the effectiveness of sodium silicate fluid injection as a soil improvement technique to mitigate the potential for liquefaction in loose sandy soils under the 2017 Halabjah earthquake. The research focuses on enhancing the strength, stiffness, and permeability of soils through chemical stabilization. The test program included evaluating the potential of sodium silicate fluid injection technology in addressing foundation liquefaction induced by seismic loadings using a shake table device. Sodium silicate solution was injected into saturated sand samples at 1:1 and 1:2 water-by-weight ratios in the stress bulb region, and the resulting changes in physical and mechanical properties were analyzed. The results indicate a significant improvement in soil strength and a significant reduction in liquefaction due to the formation of a silica gel matrix that bonds the soil particles. Tests conducted on shallow foundation specimens showed an increase in load-bearing capacity, a 57% reduction in settlement, and a 30% reduction in lateral displacement when the polymer was injected at a concentration of 1:2. When the water-sodium silicate ratio was reduced to 1:1, the improvement was further enhanced, with settlement and lateral displacement reduced by 76% and 60%, respectively, under seismic loads. Furthermore, excess pore pressure (Ru) was reduced by 25 and 33% in sand-treated soils at concentrations of 1:2 and 1:1, respectively. The proposed method offers an economical solution for liquefaction mitigation, making it suitable for urban areas and regeneration applications.
