Evaluation of clay geosynthetic barriers in landfill cover systems

Clay geosynthetic barriers (GBR-C) used in landfill capping systems have to provide sufficient low water permeability for the long-term even under critical conditions. The synthetic components need to be durable against thermal oxidation and they must also have enough strength to withstand the shear forces acting in slopes of landfill covers. Sufficticated oxidation tests like high-pressure autoclave tests as well as long-term shear creep tests have to be performed to come up with lifetimes for GBR-Cs of up to 100 years. Most critical for a GBR-C is the question of dehydration. Long-term measurements in test fields and excavations show that desiccation can and must be avoided. Under extreme conditions no "self-healing" was found.