Abstract
Laboratory tests using a small-scale model device
were carried out on leachate seepage in geo-composite barriers
due to circular geomembrane defects. Various pressures
simulating actual landfill waste loads were applied to the barrier
systems. Seepage rate, anion migration and the attenuation
tendency of a natural mineral layer were investigated. Seepage
through the geo-composite barrier-attenuation strata (AS) system
was determined under waste loads of up to 150 kPa impacting the
defected geomembrane liner. The findings revealed appreciable
reduction in seepage rate with increased pressure on the system.
The reduction is ascribed to the reduced barrier transmissivity, θ
and compressed soil layer. Data for seepage rates were compared
with predicted values from Forchheimer’s (1930) and Giroud’s et
al (1986) equations. The comparisons displayed inapplicability to
this study and to real practice, if conditions of perfect contact at
the geomembrane/soil interface are assumed. Nonetheless,
Giraud’s (1997) equation for good contact condition gave
reasonable prediction of seepage rate through geo-composite
liners with defected geomembrane.