Shear strength of geosynthetic clay liners

The geosynthetic clay liners (GCL) are composite materials whose engineering behavior is governed by geosynthetic components, sodium bentonite, and their interaction. As a result, shear strength of GCLs and GCL interfaces can be affected by many factors, including normal stress, hydration/ consolidation procedure, shear direction, shear displacement rate, drainage condition, specimen gripping surfaces, and total shear displacement. The shear strength behavior of GCLs is more complex than for any other geosynthetic material and proper care must be taken to achieve reliable results. Gripping surfaces should provide high friction against a test specimen, good drainage, and no interference with the shearing process. Clamping systems can be use to secure the ends of the geosynthetics but should not materially participate in the shearing process. GCL shear strength should be measured for hydration and normal stress conditions expected in the field.