Generalized Hoek-Brown Criterion
Inputs, constants, equivalent Mohr-Coulomb overlay, and modulus methods for rock-mass strength.
σ1 = σ3 + σci(mbσ3/σci + s)a
Generalized Hoek-Brown models nonlinear rock-mass strength from intact strength and rock-mass quality parameters. JLab computes Hoek-Brown constants, rock-mass strength metrics, deformation modulus, and an optional equivalent Mohr-Coulomb overlay.
| Input | Units / Range | Description |
|---|---|---|
| UCS Intact | Stress; min 1 MPa equivalent | Intact uniaxial compressive strength, sigmaCi. |
| GSI | 5 to 100 | Geological Strength Index used to reduce intact strength to rock-mass strength. |
| mi | Min 0.1 | Intact rock Hoek-Brown material constant. |
| Disturbance D | 0 to 1 | Disturbance factor representing blast damage and stress relaxation effects. |
| Modulus Method | Three options | Selects the rock-mass modulus equation used in the Results panel. |
| Intact Modulus | Stress; generalized HD only | Intact deformation modulus used by the generalized Hoek-Diederichs method. |
Modulus Methods
- Generalized Hoek-Diederichs (2006): uses intact modulus, GSI, and D.
- Simplified Hoek-Diederichs (2006): estimates modulus from GSI and D.
- Hoek, Carranza-Torres, Corkum (2002): uses sigmaCi, GSI, and D.
Available Outputs
- Hoek-Brown constants mb, s, and a.
- Tensile strength, uniaxial compressive strength, global strength, and deformation modulus.
- Equivalent Mohr-Coulomb cohesion and friction angle when the overlay is enabled.