Effect of overburden confining stress on hydraulic performance of geosynthetic clay liners (GCLs)

Geosynthetic clay liners are a rapidly evolving geosynthetic product used in most hydraulic barrier applications in the geo-environmental industry. Continuous research has led to new insights to overcome the shortcomings faced in deploying GCLs in the field. These include shrinkage due to shear failure on side slopes, the effect of temperature variation, and inadequacy of minimum timely confinement to achieve optimum hydraulic performance. This paper presents previous experimental data and an additional dataset from this research gathered to observe the effect of overburden confining stress on GCL hydraulic conductivity and how the findings can be used to predict the performance of a geosynthetic clay liner for a given field application. An inverse power relationship is identified between these two parameters along with the reduction in the order of the degree of hydraulic conductivity depending on the permeant material passing through. A relationship is determined to estimate the GCL hydraulic conductivity as a function of the overburden confining stress, given that it is pre or post hydrated and the permeant liquid passing through the product. It is proposed that the relationship can be used to predict the GCL hydraulic performance in the field and provide guidance in improving the serviceability of hydraulic barrier designs.