Analytical evaluation of hydraulic impact of geomembrane hole defects on composite liners

Accurate prediction of the leakage rate and water head distribution induced by defects on geomembranes (GMBs) in composite liners is important for the risk assessment of landfills and contaminated sites. However, the neglect of horizontal flow through the soil layer in existing analytical solutions for defect problems could lead to a significant underestimation of the leakage rate and its influence range, particularly in scenarios with low transmissivity, which may result in a relative error of up to −82%. In this study, analytical solutions, with consideration of horizontal flow, are proposed to evaluate the water head distribution and leakage rate of a composite liner with a circular hole defect on a GMB. The proposed models have been shown to be both accurate and reliable, with the relative error in the calculated flow rate generally being less than 1% in high interface transmissivity scenarios and less than 15% in low interface transmissivity scenarios. A novel definition for the influence radius is also proposed alongside its fitting formulas. The accurate evaluation of the impact of the hole defect would provide a basis for the total leakage rate estimation of composite liners.