Interface shear strengths for design of containment bottom liner systems

This paper investigates the effect of landfill bottom liner system base length, sideslope inclination, horizontal sideslope length, waste geometry, and waste stiffness on the mobilized geosynthetic interface strength along the base and sideslope for landfill design. Fifty-two landfill cross-section scenarios were numerically simulated to study the influence of these factors on the mobilized interface strength. The mobilized shear strength along the base of the landfill varies from peak to large displacement (LD) strength, while the mobilized shear strength on the sideslope varies from peak to residual depending on the base length, sideslope length, and sideslope inclination. These results suggest the mobilized geosynthetic interface strength along the bottom liner system is site-specific and a function of landfill waste geometry and stiffness. An increase in waste stiffness slightly reduces the interface shear displacement, whereas a decrease in stiffness leads to a significant increase in shear displacement. Specific analysis should be conducted when dealing with waste of extremely low stiffness.