The Effect of Porewater Salinity on the Physical and Mechanical Properties of Clay Soils

Saline soil refers to soil with a high concentration of ions such as sodium and chloride, which destroys structures and construction materials. Thus, it's crucial to understand their nature and behavior. This study examines the effect of salinity on the compaction and shear characteristics of clayey soils by adding two types of salt, sodium chloride, and sodium sulfate, with different concentrations (۰.۵%, ۱%, ۲%, and ۵%) to two clayey soils in Iran. Eighteen soil samples were prepared, and tests were carried out in three repetitions. The results showed that the samples' optimum moisture content and maximum dry density were within the range of ۲۰-۲۳%, and ۱.۵۶-۱.۶۳ gr/cm-۳, respectively. These changes were within acceptable tolerance limits, suggesting that salt concentration has a negligible effect on the compaction characteristics of clayey soils. However, salinity concentrations significantly affected the shear strength parameters. Adding ۰.۵% sodium sulfate decreased cohesion by ۵۰% and ۳۵% in the high and low plastic clayey soils, respectively. Similarly, ۰.۵% sodium chloride reduced cohesion by ۴۷% in the low plastic soil and ۳۵% in the high plastic soil. Furthermore, the internal friction angle increased by ۲۰% in the low-plastic soil and ۳۴% in the high-plastic soil with ۰.۵% sodium sulfate. It was also found that the type of anions and cations, as well as the plasticity of soils, play a crucial role in describing the relation between pore water salinity and shear parameters of soils.

کلیدواژه ها:

COHESION ، Internal friction angle ، Maximum dry density ، Optimum moisture content ، Saline soils