Assessment of the Permeability Characteristics in Geomaterial Capping Applications for Defective Geomembrane—A Brief Review

The specifics of soil play a significant role in enhancing the quality and sustainability of a liner system (either capping or basal liner), which is critical in the construction of a landfill. More importantly, the water permeability of the mineral layer to a large extent determines the system’s ultimate performance. Several studies have shown the significant impact of a punctured or cracked geomembrane on the water permeability of a liner system. Some researchers have conducted laboratory experiments using stiff plastic columns packed with soil filters containing perforated geomembrane layers, while others have adopted the use of empirical formulas to study and determine the hydraulic properties of the soil (water retention characteristics) within the system. However, only a few studies have focused on the effect of load concentration on the flow behavior through the barrier systems. Installed geomembranes are subject to normal loads, so it is important to evaluate the permeability behavior of a defective membrane under low applied normal stresses. Hence, this study documented past findings on the permeability characteristics under normal loading with few induced defections on the geomembrane. The body of literature essentially examined the quantitative measures of soil-water interaction and the review highlighted the following variables: the effect of compaction on the hydraulic conductivity in capping application, the effect of geomembrane defects on the flow rate to steady-state time of the top capping, flow behavior under different loads, and the influence of interfacial transmissivity and stresses on the composite liner. The objective of the research is to enhance the comprehension of the forensic geotechnical engineering aspects concerning defective geomembranes within a geomaterial system.