Shahid Beheshti University Sustainable Earth Trends 3060-6225 5 4 2025 10 01 The Effect of Porewater Salinity on the Physical and Mechanical Properties of Clay Soils 30 41 105315 10.48308/set.2025.237644.1084 EN Nader Abbasi Agricultural Engineering Research Institute (AERI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran 0000-0002-9483-0878 Farshid Taran Agricultural Engineering Research Institute (AERI), Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran 0000-0001-6086-2970 Reza Bahramloo Agricultural and Natural Resources Research Center of Hamadan Province, Agricultural Research, Education and Extension Organization (AREEO), Hamedan, Iran Journal Article 2024 11 20 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 (0.5%, 1%, 2%, and 5%) 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 20-23%, and 1.56-1.63 gr/cm^-3, 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 0.5% sodium sulfate decreased cohesion by 50% and 35% in the high and low plastic clayey soils, respectively. Similarly, 0.5% sodium chloride reduced cohesion by 47% in the low plastic soil and 35% in the high plastic soil. Furthermore, the internal friction angle increased by 20% in the low-plastic soil and 34% in the high-plastic soil with 0.5% 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. https://sustainearth.sbu.ac.ir/article_105315_3dc2e8ff8798d3b8433196891460a506.pdf