Effect of GCL Type on Downslope Erosion in an Exposed Composite Liner

Abstract

AbstractDownslope bentonite erosion in four geosynthetic clay liners (GCLs) with granular bentonite (denoted GCL1–GCL4) left covered only by a black high-density polyethylene (HDPE) geomembrane for 3.6 and 4.7 years was recently published. Reported herein are the results of a field study of the potential for erosion for seven new test sections over a 28-month period. These include four previously unstudied GCLs: two with powdered bentonite (GCL5 and GCL6), one with polymer-enhanced granular bentonite (GCL7), and one multicomponent product installed coating-up (GCL8). One GCL (GCL2) known to experience erosion below an exposed black geomembrane was installed beneath both a black and a white exposed geomembrane and also in a section where the composite liner was promptly covered by 0.3 m of gravel. After 28 months, there was significant erosion of GCL2 and GCL7, but no significant erosion of GCL5, GCL6, GCL8, or GCL2 covered by 0.3 m gravel.