Inclined multi-layered barriers can be used to protect
underlying waste storage facilities. The intended barriers can confine
infiltration through the implementation of the capillary barrier effect. In
this study, the effect of rainfall, evaporation, and transpiration on the
hydraulic properties of inclined covers was assessed by performing simulations
using HYDRUS-2D numerical models. The material layers included clay loam soil
as a seepage control layer, sandy soil as a moisture retention layer, and
gravel as a capillary break layer. The numerical analysis simulated 20 years of
climatological data (2000-2019) from Windsor, Canada, representing humid
conditions with variable precipitation and evapotranspiration patterns.
Key quantitative results indicate that 21.09% of cumulative
net rainfall was converted to lateral drainage along the sloped interfaces,
while 78.91% of infiltrated water eventually exited through the bottom boundary
as vertical percolation. The mean flux across the bottom boundary was 206.70
cm/day (2.39×10⁻⁶ m/s), demonstrating minimal deep percolation under the
prevailing climatic conditions. Lateral diversion occurred at the interface
between the seepage control layer and moisture retention layer due to the
significant slope (10%) and contrasting hydraulic properties of adjacent
layers. At reduced degrees of saturation, water movement between layers was
restricted by low hydraulic conductivity, with the negative pressure head in
the seepage control layer having minimal effect on water content in underlying
layers.
This modelling approach, which uniquely combines an inclined
multi-layer configuration with long-term transient climatic forcing,
demonstrates that properly designed capillary barrier covers can effectively
minimise leachate generation in waste containment systems. The findings provide
quantitative design guidance for landfill covers in humid regions, showing that
10% slopes with layered clay loam, sand, and gravel materials achieve the
capillary barrier effect under variable climatological conditions. The
performance of this protective earthen cover can be guaranteed under the
current climatological conditions, offering engineers a validated numerical
framework for optimising waste containment cover designs.
Author(s) Details
Mohammad Ali Hagh Shenas
Department of Civil
Engineering, Razi University, Kermanshah, Iran.
Hassan Sharafi
Department of Civil
Engineering, Razi University, Kermanshah, Iran.
Please see
the book here :- https://doi.org/10.9734/bpi/ccert/v1/7166
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