Tensile Strains in Geomembrane Landfill Liners

Abstract

A geomembrane (GMB) liner is a key component of the barrier system in many modern engineered landfills. In combination with a clay liner, the GMB minimizes contaminant migration to groundwater and surface water. GMBs in landfill applications are mostly made from high-density polyethylene (HDPE). When in contact with landfill leachate, the HDPE GMBs experiences significant aging and loss of mechanical properties with time. In particular, a loss in stress crack resistance combined with excessive tensile stress/strain can result in GMB cracking and ultimately failure. Thus, to ensure good long-term performance, the maximum tensile strain sustained by an HDPE GMB should be limited to an acceptable level. Both the local GMB indentations induced by gravel in an overlying drainage layer or underlying clay liner and the down-drag load in the GMB on side slopes with settlement of the waste can cause significant tensile strains in HDPE GMBs. This paper reviews key research examining tensile strains developed in GMBs from both sources.