Long term performance of bituminous and modern geomembrane liners with high interface shear strength

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Geosynthetic barriers are widely used in geoenvironmental projects such as landfills and many mining applications. These mega fills/ponds (sometimes >10M m2) are now required to be constructed on geosynthetic liners. The liner systems often comprise a polymeric geomembrane over a low permeability soil layer to function as a barrier against contaminant migration into the surrounding environment. Aside from catastrophic failures due to poor installation or sudden application of external forces, these geomembranes are typically robust in the short term. However, geomembranes can fail in long term due to their slow aging process (i.e. degradation) resulting in contaminant migration to the environment and/or the instability of the side slope liner. Either would involve major subsequent remediation costs. To ensure that our environment is protected during mineral extraction and waste disposal operations, it is critical that geomembranes have an adequate and known service life. Today, many innovative geomembranes are offered for designing landfills and mining facilities with little to no supporting research on their durability. Thus, there is a strategic need to understand and evaluate the longevity of these geomembranes to minimize negative interactions with the environment during the design life of the containment facility (several decades to centuries).The proposed research will capitalize on the unique barrier system evaluation infrastructure available at Queen's to conduct novel state of the art research examining the chemical durability of modern polyethylene and bituminous geomembranes with high interface shear properties. For the first time, the performance of these geomembranes will be further examined under shear to investigate the effect of aging on the interface shear strength of the liner on the side slopes of landfill and mining facilities. Furthermore, numerical modeling will be used with the data collected during the experimental program to examine, for the first time, the effect of aging of the geomembrane on the geotechnical stability of the side slope liners.This research aims to establish an evidence based rigorous understanding of the performance of geomembranes offered today in the market and will be relied on to protect our environment for the coming decades/centuries. This understanding will benefit the Canadian geosynthetic community (consultants, manufacturers, regulators) in achieving better design for barrier systems, and the public by protecting our surface and ground waters against contamination while establishing the most efficient use of resources and tax dollars. This program will train 3 PhD, 2 MSc, and 4 undergraduate students that will involve skills in conducting unique experiments and leading-edge analysis techniques in performance evaluation of geosynthetic liners, who will carry their unique knowledge and skills to industry and academia.