The lining of steep landfill slopes in South Africa and the applicability of the "minimum requirements for waste disposal by landfill" by the Department of Water Affairs and Forestry.
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Date
2013
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Abstract
In August 2013, the landfill liner designs prescribed by the Minimum Requirements for
Waste Disposal by Landfill was superseded by the containment barriers of landfills, now
prescribed by the National Norms and Standards for Disposal of Waste to Landfill. These
newly prescribed lining systems were assessed in terms of mineral layers, geosynthetic
materials and alternatives of equivalent performance. A Class B landfill lining system was
then selected to determine its performance on various slope angles.
Various geosynthetic materials were tested for their interface shear strength parameters using
a ring shear apparatus. These shear strength parameters were then used as inputs to calculate
the selected factors of safety. The factors of safety for stability on slopes of 1:4, 1:3, 1:2 and
1:1 using 2-D limit equilibrium analyses were then calculated. The factors of safety for the
integrity of the selected geosynthetic materials were also calculated.
Where factors of safety were found to be less than the accepted value of 1.5, the lining
system components were replaced with geosynthetics of equivalent performance and the
factors of safety for stability on slopes of 1:4, 1:3, 1:2 and 1:1 were recalculated. Where
factors of safety were still below 1.5, another geosynthetic in the form of veneer
reinforcement was used to increase the factor of safety to an acceptable value. Alternative
single sided textured and double sided textured HDPE geomembrane liners were also used to
help increase the interface shear parameters.
The findings from this dissertation will provide a greater understanding to landfill designers
about the selection of materials of equivalent performance, the interface shear strengths of
the materials tested and the performance of various landfill lining systems on steep and
varying slopes. This research will also assist landfill designers to determine the relationship
between various lining systems, the slope angles and factors of safety. Although this
research will provide assistance with the above concepts, site specific testing is still required.
Finally, the recommendations for further research on the lining of steep slopes are also
highlighted.
Description
M. Sc. Eng. University of KwaZulu-Natal, Durban 2013.
Keywords
South Africa. Department of Water Affairs and Forestry., Hazardous waste--South Africa--Management., Sanitary landfills--Linings--South Africa., Waste disposal in the ground--South Africa., Theses--Environmental engineering.