Experimental Study of the Effect of Lime in the Process of Self-Healing and Dispersivity of Clay Soils (Case Study: Gordyan Dam)

Compact clay layers are one the most impermeable layers. Dispersivity and cracking of clay layers are among the factors that reduce the efficiency of clay and necessitate clay stabilization. Clay healing properties and the importance of self-healing cracks in clay layers as one of the characteristics and attributes of clay in recent years have been studied. In this research, the self-healing performance of clay layers due to the addition of lime to the clay materials of Gordyan dam borrow pit (Gargar) was investigated. For this purpose, two dispersive (S2 and S3) soil samples (ND3 and ND4) were investigated by adding lime to the extent 0.25, 0.5, 1 and 2%, and Double Hydrometer, Atterberg limits and Pinhole tests of dispersivity and self-healing were investigated. The results showed that by adding 1% of lime to clay, the range of plasticity index increased and the discharge rate of the pinhole test for both samples was 28% and the final diameter of the sample for both samples decreased by 67%, indicating an improvement in self-healing process and a reduction of dispersivity and becoming non-dispersive soil (ND1). The results also showed that pinhole testing has reliable and more accurate results than other tests in determining soil dispersivity.