➀ 일반사면:
\[
F_s = \frac{c \cdot l + (W \cos \theta - u \cdot l) \tan \phi}{W \sin \theta}
\]
➁ 무한사면:
\[
F_s = \frac{c + (\gamma \cdot z \cos^2 \beta - u) \tan \phi}{\gamma \cdot z \sin \beta \cos \beta}
\]
➂ 암사면(보강 포함):
\[
F_s = \frac{cA + (W \cos \theta - U - V \sin \beta + T \cos \theta) \tan \phi}
{W \sin \beta + V \cos \beta - T \sin \theta}
\]
➀ Skempton ( \( \phi_u = 0 \) ): \[ F_s = \frac{M_r}{M_d} = \frac{T \cdot R}{W \cdot x} \]
절편법:
\[
F_s = \frac{M_r}{M_d} = \frac{\sum (c \cdot l + N \tan \phi)}{\sum W \sin \alpha}
\]
Fellenius:
\[
F_s = \frac{\sum \left[ c \cdot l + (W \cos \alpha - u \cdot l) \tan \phi \right]}{\sum W \sin \alpha}
\]
➀ Fredlund (독립변수 접근):
\[
\tau_f = c' + (\sigma_n - u_a) \tan \phi' + (u_a - u_w) \tan \phi_b
\]
➁ Bishop (유효응력 접근):
\[
\tau_f = c' + (\sigma - u_a) \tan \phi' + \chi (u_a - u_w) \tan \phi'
\]
➂ Lu (겉보기 점착력 포함):
\[
\tau_f = c' + c'' + (\sigma - u_a) \tan \phi'
\]