Brittle rupture of an aged HPDE geomembrane at local gravel indentations under simulated field conditions

TLDR

The study examines the susceptibility of a 1.5 mm HDPE geomembrane to brittle rupture from long‑term stress cracking in a simulated municipal solid waste landfill liner. Geomembranes were pre‑aged in leachate at 85 °C to reduce crack resistance, then incorporated into composite liner simulators with a geosynthetic clay liner, sand foundation, geotextile protection, and drainage gravel, allowing simulation of field conditions such as temperature, pressure, leachate flow, and exposure. Brittle rupture occurred on gravel indentation side slopes between 55 °C and 85 °C, with higher temperatures shortening rupture time and increasing tensile strain, and Arrhenius analysis yielded an activation energy of 112 kJ mol⁻¹.

Abstract

ABSTRACT: The susceptibility of a 1.5 mm thick high-density polyethylene geomembrane to brittle rupture from long-term stress cracking in a simulated municipal solid waste landfill liner is examined. The geomembrane was pre-aged in a leachate at 85°C to lower the notched constant tensile load stress crack resistance of the geomembrane to about 75 h. The aged geomembrane was then used as part of a composite liner system in geosynthetic liner longevity simulators (GLLSs) with a geosynthetic clay liner and sand foundation layer below the geomembrane and a 560 g/m 2 geotextile protection layer and 50 mm drainage gravel above the geomembrane. The GLLSs allow the simulation of field conditions including elevated temperatures, overburden pressure, leachate circulation, and composite liner exposure conditions. The geomembrane experienced brittle rupture on the side slopes of the local gravel indentations for temperatures between 55 and 85°C. The higher the liner temperature, the shorter the time to rupture and the higher the tensile strain at rupture. Arrhenius modelling of the test data gave an activation energy of E a = 112 kJ/mol.