Dike flow and heat transfer with geomembrane defects: experiment and simulation

Damage to geomembranes in dikes can result in leakage. To investigate the efficacy of heat tracing in the detection of geomembrane defects, a series of laboratory experiments was conducted using a self-made two-dimensional sand trough and temperature sensors and the heat-tracing response of geomembrane defects was evaluated. The findings indicate that the temperature distribution within a dike, resulting from geomembrane defects, exhibits a comparable spatial–temporal pattern to that of the seepage field. Furthermore, the heat-tracing response is discernible. A flow–heat coupling model (FHCM) was constructed based on the heat transfer theory of porous media and saturated–unsaturated seepage theory. The accuracy of the FHCM was tested by comparison with the experimental results. The numerical simulation results showed that the superposition of multiple geomembrane defects results in an acceleration of leakage. In order to reduce the amount of debugging work required for model parameters, the Morris method was used to analyse the global sensitivity of six parameters within the FHCM. The parameter exhibiting the greatest sensitivity was found to be the hydraulic conductivity. This work provides a reference for wide application of the heat-tracing technique.