Optimum Tensile Strength of Geomembrane Liner for V-Shaped Anchor Trenches Using Target Reliability Approach

This paper presents the target reliability based design framework for V-shaped anchored trenches to resist the sliding action and pull-out of geosynthetic liners. V-shaped anchor trenches are subject to various uncertainties arising from inconsistency in parameter estimation, improper compaction of cover/backfilled soils, field construction practices, the assumption of relative slippage at soil-liner interface and invention of new design methods. Therefore, based on the compilation of interface friction angles between different types of geomembranes (GMB) and granular soils according to several published studies, the mean, standard deviation, and coefficient of variation are computed using statistical analysis. Moreover, a framework for reliability based design is presented by considering the unit weights of backfill and cover soil, interface friction angle and allowable GMB tensile force. The optimum allowable GMB tensile force needed to maintain the stability against pull-out failure by targeting various reliability indices is obtained for various design parameters. The obtained results highlight the potential benefits of reliability methods and encourage their implementation during the design of MSW landfills.