Liquid flow through composite liners due to geomembrane defects: Nonuniform hydraulic transmissivity at the liner interface

Rates of liquid flow through composite liners are intimately linked with th e existence of a transmissive layer between the soil liner and the geomembr ane. The aim of this paper is to propose analytical solutions for estimatin g the rate of liquid flow through composite liners for the case where two z ones of different hydraulic transmissivities coexist in the transmissive la yer. Solutions are given for both the axisymmetric and two-dimensional case s. The development of these analytical solutions is directly based on solut ions that have been proposed previously for uniform hydraulic transmissivit y. Results tend to show, for the simple cases evaluated, that, in situation s where there is variable hydraulic transmissivity, neglecting the variabil ity can result in a significant overestimation of the rate of liquid flow. This preliminary approach shows the importance of taking into account a rea listic distribution of hydraulic transmissivity in attempts to estimate the rate of liquid flow through composite liners and highlights the need for m ore research in this area.