Assessment of asperities geometry influence on MSW landfill critical interface side-slope stability using probabilistic analysis

Abstract

Geomembrane asperities are surface protrusions which distinguish smooth geomembranes from textured geomembranes. Asperities possess geometrical features such as height and concentration and are hypothesised to develop high interface shear strength, resist sliding and increases stability. To date, many textured-geomembranes with different asperity geometries have been manufactured and used in landfill linings together with geosynthetics like geotextiles. Previous studies have considered the effects of asperity geometries to geomembrane/geotextile interface shear characteristics. However, limited studies have considered the effects of asperity height and concentration on the landfill side-slope liner factor of safety (FoS) using the geomem-brane/geotextile critical interface as the point of reference. Thus, this study was aimed at investi-gating the influence of asperity geometries on liner stability. This study utilized experimental results from direct shear test (i.e. friction angle and adhesion) and performed probabilistic stability analysis using SLIDE2. Available results indicated that FoS increased as both asperity concen-tration and height increased. However, asperity-height increased beyond 1.2 mm mobilized FoS reduction. Therefore, obtaining an optimised liner stability factor is hinged on selecting the ap-propriate geomembrane asperity geometry at the critical geomembrane/geotextile interface.