Slope stability

Infinite-slope factor of safety and effective-stress calculations.

Infinite-slope stability calculations.

bishop_chi

bishop_chi(theta: ndarray, *, theta_r: float, theta_s: float) -> np.ndarray

Bishop/Vanapalli-style effective-stress parameter.

factor_of_safety_profile

factor_of_safety_profile(z: ndarray, pressure_head: ndarray, theta: ndarray, *, hydro: HydraulicProperties, strength: StrengthProperties) -> np.ndarray

Compute infinite-slope factor of safety along a depth profile.

FS = tan(phi)/tan(delta) + [c' - chi * gamma_w * psi * tan(phi)] / [gamma * z * sin(delta) * cos(delta)]

Adapted from Baum et al. (2010), Eq. (18), with the unsaturated effective-stress correction in section 6, paragraph 42; also Baum et al. (2008), Eq. (18). Constant soil unit weight and numerical clipping are package choices.

The sign convention is: - positive pressure head reduces stability; - negative pressure head represents suction and increases stability through the chi-scaled term.