Critical interfaces of multilayer geosynthetic liner systems

Abstract

A two-part wedge method for the translational failure analysis of landfills was used to find an effective method to determine the critical interface having the minimum factor of safety for landfills with multilayer geosynthetics. The critical interface usually does not appear at the same interface as the base and back slope. A simple method is presented to determine the minimum factor of safety and critical interface. Furthermore, the failure can change from one interface to another with varying the waste depth. Using only one critical interface to conduct stability analysis will cause an unsafe result. There may be multiple failure interfaces at the shift points for a multilayer liner. The depth of the shift points varies with changes in the depth, top width, front slope and back slope of the waste. It is important to ensure that the minimum factor of safety at the critical interface is always equal to or greater than a targeted value to achieve landfill stability under various conditions.