Safety factors comparison of landfill lining components using single & double interface shear strength results

¹ Department of Civil Engineering, University of Cape Town, Private Bag X3, Rondebosch, Cape Town 7701, South Africa
² Department of Civil and Environmental Engineering, Makerere University, Kampala 7062, Uganda

^* Corresponding author: sylvic001@myuct.ac.za

Abstract

The design of a competent basal lining system is crucial in ensuring a long-lasting and functional engineered municipal solid waste (MSW) landfill. However, due to the inclusion of numerous geosynthetics and geomaterials forming a multi-layered lining system, there rises an uncertainty on determining the critical or weakest interface. This is exacerbated by the different properties offered by these lining materials and their inter-crossing functions in landfills. According to ASTM D5321-20 standard, the interface shear strengths used in design of bases and side-slopes of lining systems are determined through a single interface testing configuration. However, minimal research has been done to evaluate the consequences of multi-interface testing configurations on the minimum factors of safety (FoS_min). The present study was thus conducted to further investigate this phenomena while establishing the appropriateness of double interface testing configuration using large direct shear equipment. It was found that, the difference in the FoS_min was insignificant for critical interfaces observed under single and double interface testing configurations.