Experimental study of self-healing capacity of geosynthetic clay liners under leachate

• Published in: Arabian journal of geosciences Vol. 15; no. 19
• Main Authors: Shahrivar, Payam Mohammadi, Shahir, Hadi, Asadollahfardi, Gholamreza
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2022; Springer Nature B.V
• Subjects: Bentonite; Clay; Clay liners; Drinking water; Earth and Environmental Science; Earth science; Earth Sciences; Geosynthetics; Groundwater; Landfill; Landfills; Leachates; Original Paper; Perforation; Soil compaction; Waste disposal sites; GCL; Self-healing; Landfill; Leachate
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-10835-7

To prevent leachate movement toward the soil under the landfill’s bottom, different liners such as compacted clay layers, geomembranes, and geosynthetic clay liners (GCLs) are used. One of the problems with the use of GCL is the possibility of perforation when it is installed on the landfill bottom, leading to leachate infiltration to the ground layers or the groundwater. If the bentonite can swell in contact with leachate, as it does in the contact with water, the GCL will be self-repairable. In this paper, the self-healing properties of two types of GCLs under leachate are studied using an experimental cell designed for this purpose. The specimens were deliberately pierced and inserted into the bottom of the cell, and the time of its relative self-healing was recorded. The experiment was performed with tap water and leachate, and the leachate was collected from the Kahrizak landfill in Tehran. Three holes with diameters of 1, 2, and 3 mm were created in both GCLs. For the hole diameter of 1 mm under the tap water, the full self-healing was reached after about 8 h, and for the hole diameters of 2 and 3 mm, the average self-healing of GCLs after 1 day was obtained 97% and 75%, respectively. Under leachate, the full self-healing for the hole diameter of 1 mm was reached after about 12.5 h, and the average self-healing after 1 day obtained 58.5% for the hole diameter of 2 mm. These results indicate that the type of liquid and the size of the hole considerably affect the self-healing property of GCLs. GCL under leachate self-heals more slowly than tap water, and increasing the hole diameter reduces the self-healing ability in all samples using either tap water or leachate.