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Abstract Gypseous soils, characterized by high gypsum content, are highly susceptible to significant settlement upon exposure to water, posing serious challenges to structural stability. This study investigates the stabilizing potential of nano-silica in mitigating collapse behavior of gypseous soil containing 80.4% gypsum, under leaching conditions. A custom-designed physical model a steel container (700 × 700 × 700 mm) was employed to simulate field loading conditions using a hydraulic jack, while controlled leaching was applied over a 12-day period under constant vertical load. Nano-silica was introduced at dosages of 1, 2, 3, 4, and 5% by dry mass of soil. The results indicate that nano-silica significantly reduces leaching-induced settlement through improvements in soil cohesion, reduction in permeability, and inhibition of gypsum dissolution. The most effective stabilization was achieved at 4 and 5% nano-silica content, where settlement was reduced by up to 47.9%, accompanied by a marked decrease in both drainage water volume and total dissolved salts (TDS). Microstructural analysis revealed that nano-silica induces the formation of a denser, more cohesive matrix, which enhances resistance to collapse and preserves the load-bearing capacity of the soil. These findings highlight nano-silica as a cost-effective and practical additive for improving the geotechnical behavior of gypseous soils, particularly in arid and semi-arid regions where hydraulic exposure poses a persistent risk to infrastructure.
Karkush et al. (Mon,) studied this question.