Mohr-Coulomb Criterion

The Mohr-Coulomb criterion is the most common failure criterion encountered in geotechnical engineering. Many geotechnical analysis methods and programs require use of this strength model. The Mohr-Coulomb criterion describes a linear relationship between normal and shear stresses (or maximum and minimum principal stresses) at failure.

The Mohr-Coulomb criterion implementation in RocData can be used to analyze both direct shear and triaxial test data.

The direct shear formulation of the criterion is given by Eqn.1:

                    Eqn.1

The Mohr-Coulomb criterion for triaxial data is given by Eqn.2:

          Eqn.2

where c is the cohesive strength, and is the friction angle.

Equivalent Mohr-Coulomb Parameters

If you are working with one of the non-linear strength criteria in RocData (e.g. Generalized Hoek-Brown, Barton-Bandis or Power Curve), then the equivalent Mohr-Coulomb linear failure envelope is automatically computed over a given stress range. See the Equivalent Mohr-Coulomb Parameters topic for more information.