Factor of Safety
Fs = [c'L + W*cos(β)*tan(φ')] / [W*sin(β)]
Factor of Safety (Fs): 2.41
What is this for?
This equation calculates the Factor of Safety (Fs) for a landfill slope. It determines if a slope is stable or at risk of failing (a landslide).
What to look for: A Factor of Safety greater than 1.5 is generally considered safe for long-term stability. A value below 1.2 indicates a high risk of failure. The diagram color-codes the risk: green (safe), yellow (caution), and red (unsafe).
Fs: Factor of Safety - A ratio of forces resisting failure to forces driving failure.
c': Effective Cohesion - The "stickiness" of the soil or waste material.
L: Length of Failure Plane - The length of the surface along which a slide could occur.
W: Weight of Slice - The weight of the potential sliding block of material.
φ': Effective Angle of Internal Friction - A measure of the material's shear strength.
β: Slope Angle - The angle of the landfill slope.