Effect of effective overburden pressure on geomembrane/soil interface transmissivity

Fluid flow through a defect in the geomembrane of a composite geomembrane/soil liner (flow rate tests) and interface transmissivity tests between a geomembrane and a soil layer were conducted. The results are compared, and the effect of overburden pressure p′ on the geomembrane/soil interface transmissivity θ and interface thickness t_in is investigated. For flow rate tests, the values of θ are back-calculated using the Rowe and Touze-Foltz et al. solutions. With known values of θ, t_in is calculated using Newton's viscosity law for fluid flow between two parallel plates. For the conditions considered, it is shown that θ and t_in reduce significantly with increasing p′. Comparisons are made between the calculated values of θ and t_in and those reported in the literature. It is shown that ignoring the effect of p′ on θ and t_in can lead to gross overestimation of these parameters.