Leakage and Contaminant Transport through a Single Hole in the Geomembrane Component of a Composite Liner

• Published in: Journal of geotechnical and geoenvironmental engineering Vol. 139; no. 3; pp. 357 - 366
• Main Authors: Rowe, R. Kerry, Abdelatty, Khaled
• Format: Journal Article
• Language: English
• Published: Reston, VA American Society of Civil Engineers 01.03.2013
• Subjects: Applied sciences; Buildings. Public works; Contact; Contaminants; Exact sciences and technology; Fluid dynamics; Fluid flow; Geotechnics; Hydraulics; Leakage; Liners; Miscellaneous; Pollution; Sand; Soil and sediments pollution; Technical Papers; Leakage; Geosynthetics; Geosynthetic material; Landfills; Leak; Geomembrane; Geomembranes; Composite liner; Experimental study; Soil pollution; Geosynthetic clay liner; Advection; Composite materials; Clay liners; Landfill; Transport; Contaminant
• ISSN: 1090-0241; 1943-5606
• DOI: 10.1061/(ASCE)GT.1943-5606.0000773

AbstractThe migration of contaminants through a 10-mm-diameter hole (0.785 cm2) in a geomembrane in direct contact with a geosynthetic clay liner (GCL) and adjacent silty sand is examined. Experiments were conducted in four 0.6-m-diameter cells at a vertical stress of 100 kPa and hydraulic head differences of 0.3 and 1 m. The system was first permeated with distilled water until steady-state flow was attained (the reference case). After 280 days the permeant was changed to a NaCL solution. After 800 days of permeation with 0.14 M NaCl solution there was only a 3% increase in the flow (leakage) compared with the reference case despite up to almost an order of magnitude increase in GCL permeability near the hole. The wetted radius at the end of the experiments was inferred by injection of dye and was found to be about 0.1–0.15 m. This provides the first experimental evidence in support of theoretical predictions that, when the geomembrane is in direct contact with a GCL, leakage through a hole is primarily controlled by the interface transmissivity rather than the GCL hydraulic conductivity when there is interaction between the permeant and the GCL. The observed chloride distribution in the silty sand at the end of the experiments is reported.