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Cover Slope Stability:Landfill Gas Pressure - Design Calculator
This calculator determines the safety factor of slope stability of a landfill cover subject to LFG pressure underneath a geomembrane liner.
Landfill gas (LFG) pressure underneath a lined cover system can significantly reduce the effective normal stress on the liner, which can affect cover soil stability. Large-scale landfill cover slope failures have been recorded over the past decade to be directly attributed by an inadequate LFG venting layer. The landfill gas pressure relief layer calculator can be used to determine the required gas transmissivity for LFG relief layer based on LFG generation rate, maximum LFG pressure, and spacing between strip drains.
where:
FS |
Safety factor for slope stability |
h |
Thickness of cover soil perpendicular to the slope (m) |
β |
Slope inclination angle (o) |
| δ | Geomembrane-soil interface friction angle (o) |
| c | Geomembrane-soil interface adhesion (kPa) |
| γ | Total unit weight of the cover soil (kN/m3) |
ug |
LFG pressure (kPa) |
Thiel, R.S. (1998), "Design Methodology for a Gas Pressure Relief Layer Below a Geomembrane Landfill Cover to Improve Slope Stability", Geosynthetic International, Vol. 5, No. 6 pp. 589-617.
Copyright 2001 Advanced Geotech Systems. All rights reserved.