shaft.interface_alpha()

Interface factor on the residual strength of liquefied soil.

Usage

Source

shaft.interface_alpha(
    sr,
    sigma_v0,
    psi_nc=0.22,
)

Parameters

sr: float

Residual strength, ksf.

sigma_v0: float

Vertical effective stress, ksf.

psi_nc: float = 0.22

Normally consolidated undrained strength ratio.

Returns

float

min(1, sqrt(psi_nc / psi)) for psi = sr / sigma'v0 <= 1 and sqrt(psi_nc) psi**-0.25 above; 1 when the inputs are not positive.

References

Randolph and Murphy (1985), as adopted in API RP 2A.