Waste/Lining System Interaction: Implications for Landfill Design and Performance

Abstract

Despite the relative maturity of landfill design practice, world-wide there are still significant numbers of large scale failures of waste bodies, often incorporating the lining system. In addition, there is growing evidence that post waste placement deformations in the lining system are leading to loss of function (i.e. discontinuous drainage layers, loss on protection and leaking liners). Best practice has established that both stability and integrity of the lining system must be assessed during the design process, and specifically that interaction between the waste body and lining system should be considered both in the short-term (i.e. during construction) and long-term (i.e. following waste degradation). The paper introduces available analysis approaches, reviews knowledge of waste behaviour required for such analyses and provides guidance on the mechanisms to consider. The need for field monitoring to validate numerical models is established as is the need for extensive measurements of waste mechanics properties linked to a standard classification system to aid comparison and use. The benefits of using probability of failure analysis to incorporate material and test variability in design are highlighted.