Performance Testing of Landfill Geoprotectors: Background, Critique, Development, and Current UK Practice

Geomembrane basal landfill liners are typically overlain by a stone drainage layer with a geoprotector layer placed between the drainage layer and the geomembrane to protect the geomembrane from environmental stress cracking caused by pressures transmitted through the stone drainage layer. The effectiveness of the geoprotector layer (which may be mineral or synthetic, or a combination of both) is demonstrated by means of a cylinder test using site specific materials. Current United Kingdom (UK) practice is to follow the Environment Agency (EA) method for this performance test, which evolved from guidelines produced in the early 1990s by the German “Quo Vadis Schutzlagen” working party. This paper reviews the background information for the test, in particular, the perceived deficiencies in the original German guidelines, and, hence, the need for the new EA methodology. A commentary on the new EA test method from the perspectives of regulator, designer, manufacturer, and test institution is included. The EA test standardises the apparatus, testing procedure, method of measuring deformations, and calculation of local strains.