Effect of differential settlements on the sealing efficiency of GCLs compared to CCLs: Centrifuge Study

Abstract

Geosynthetic clay liners (GCLs) are being used as an alternative to compacted clays in landfill cover systems because of their very low hydraulic conductivity to water and ease of placement. The main objective of this paper is to examine the performance of GCLs subjected to continuous differential settlements during a centrifuge test at 40 gravities. This paper presents results to two centrifuge model tests, one on clay-based cover system and another on GCL-based cover system. Both models were subjected to an overburden equivalent to that of landfill covers and are instrumented to measure sealing efficiency at the onset of differential settlements. Limiting maximum distortion level at which the barrier system loses it sealing efficiency could be established. For the type of cover systems investigated, the ability of GCL-based cover system to withstand differential settlements without losing their sealing efficiency was found to be superior to that of clay based cover system.