Soil compaction commonly used to minimize the leaching of pollutants into the soil and groundwater. This study expresses the results of an experimental method performed to investigate the influence of clay content and compaction conditions on the soil water retention cure parameters and saturated hydraulic conductivity of a proposed clay liner. Compacted samples of three soils with different clay percentages were prepared for different compaction energies (reduced (RC), standard (SC) and modified compaction (MC)) and different water contents (dry, wet, and optimum). The experimental data were fitted to four commonly models such as Brooks-Corey, Van Genuchten, Fredlund and Xing four-parameter and Fredlund and Xing five-parameter. Each model provided a satisfactory fit to the experimental data. R2 and RMSE ranged between 0.84 to 1 and 0.0002 to 0.051, respectively. In Van Genuchten model, the soils with higher plasticity index have lower α and larger n. However, the individual parameters obtained from the curve fit varied significantly among models. The hydraulic conductivity of the clay soil in modified compaction energy ranged between 8.8 × 10−7 and 1.5 × 10−6 . Generally, the results indicated that soil compaction has increased the maintenance of soil water retention and also the modified compaction, dry of optimum, had the lowest Ks.
