Modified lade criterion

Input(s)

$S_{a}$: Principle Stress (psi)

$S_{b}$: Intermediate Stress (psi) $S_{c}$: Minimum Stress (psi)

$P_{a}$: Pressure $(\mathrm{psi})$

m: Material Strength Constant (dimensionless)

Output(s)

$I_{a}$: First Invariant of Stress Tensor (psi)

$I_{c}$: Third Invariant of Stress Tensor (psi3)

$\eta$: Lades Coefficient (dimensionless)

Formula(s)

Reference(s)

Mark D. Zoback, Reservoir Geomechanics, Cambridge University Press, UK, Page: 99.