Compressibility and strength enhancement of clayey soil using magnesium chloride solution

One of the most important problems of clayey soils are their susceptibility to compression when loads are applied due to weak bonds that allow water to enter and exit between soil particles. In this research, clay soil with a clay content of (72%) from Salah Al-Din governorate, Iraq was used. This soil was treated with magnesium chloride solutions at different concentration ratios (5, 10, and 15%). Compressibility and strength tests were performed on natural and treated soil, results showed that the compression decreased significantly with increasing magnesium chloride concentrations, the final strain after unloading was (1.8, 1.72, 1.0, and 0.95) % at concentrations of (0, 5, 10, and 15) % respectively. It is also noted a significant increase in the unconfined compression strength with enhancing ratio of (21, 27, 38) % at enhancing ratios of (5, 10, 15) % respectively. For direct shear test, cohesion of soil increased by (66, 94, 97) %, while the increase in value of soil’s friction angle was (13, 5, 7) % at a solution content of (5, 10, 15) %. The results shows that the enhancement in soil strength is small and almost constant when the magnesium chloride content increases by more than 10% due to soil saturation.