Hoek-Brown Rock Mass Strength Criterion

1. Rock Mass & Intact Properties

Intact UCS σci (MPa)

Geological Strength Index (GSI)

Intact Constant mi

Disturbance Factor D (0-1)

Intact Rock Modulus Ei (GPa)

2. Application & Confinement (σ'3,max)

Application Type

Depth / Height H (m)

Unit Weight γ (kN/m³)

Custom σ'3,max (MPa)

Global Strength σcma

28.4 MPa

σc: 18.2 MPa

Eq. Friction φ'

47.8°

At σ'3max: 12.5 MPa

Eq. Cohesion c'

3.62 MPa

3,620 kPa

Deformation Erm

26.8 GPa

σtm: -0.15 MPa

Hoek-Brown mb: 7.82

Hoek-Brown s: 0.0286

Hoek-Brown a: 0.502

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