Influence of saline treatments on the geomechanical behavior of clayey soils

Expansive clay soils are made up of many minerals such as hydrated aluminum silicates, which have a fibrous, laminated structure and give the soil a high water absorption capacity. The volumetric change of such soils in the presence of water poses serious stability problems. Improving soil performance is an important process in the construction of geotechnical works on problem soils. There are several methods to solve these issues, among them stabilization by injection of chemical solutions into the soil. In this context, this study focuses on the injection of chemical solutions in a clay taken from the region of Didouche Mourad, in the district of Constantine in the north east of Algeria. In the first part, the physical and mechanical characterization of clay was conducted in a series of laboratory tests. The results obtained show that our clay exhibits high swelling potential (Swelling potential: 3.87%), very plastic (plasticity index: 38.55%) and moderately compressible. The second part presents the treatment of swelling clays by adding Potassium chloride (KCl) and sodium chloride (NaCl) at different concentrations of 0.5, 1 and 2 mol/l. The results show that salt addition markedly improves soil behavior, with swelling reduced by 25–72% at 0.5–1 mol/l and by up to 75% at 2 mol/l. Both salts were effective, with KCl slightly outperforming NaCl. This confirms that concentrated salt solutions are a promising method for stabilizing expansive clays in geotechnical applications.