Joint Properties
Joints can be defined in EX3 by selecting:
- Materials > Joints > Joint Properties
Stiffness
The stiffness in normal/shear directions can be applied as shown in the dialog. The units are defined from the project settings.
Failure Criterion
Similar to Material Properties, the failure criterion options in Joints can be assigned with Elastic, Mohr-Coulomb, and Barton-Bandis failure criterion.
Mohr-Coulomb
For the Mohr-Coulomb criterion you must define the following parameters:
- Peak Cohesion
- Peak Friction Angle
- Peak Tensile Strength
The Barton-Bandis strength model can be used to model the shear strength of a joint. The Barton-Bandis strength model establishes the shear strength of a failure plane as:
where Φr is the residual friction angle of the failure surface [Barton and Choubey, 1977],
JRC is the joint roughness coefficient, and JCS is the joint wall compressive strength.
For further information on the shear strength of discontinuities, including a discussion of the Barton-Bandis failure criterion parameters, see Chapter 4 of Practical Rock Engineering by Dr. Evert Hoek, available on the Rocscience website.