Theoretical Basis

Factor of safety $\mathrm{FS}=\frac{C+\cos \mathrm{\theta }\left[1-\mathrm{wr}\right]\tan ɸ}{\sin \mathrm{\theta }}$ where

1. Relative Wetness $w=\frac{D_w}{D}=\mathrm{Min}\left(\frac{Ra}{T\sin \mathrm{\theta }},1\right)$
2. Dimensionless Cohesion $C=\left(C_r+C_s\right)/\left(h{p}_{s}g\right)$
   Density Ration $r=p_w/p_s$ (assumed a constant of 0.5)

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