Strength and elastic properties of materials (rock or soil) are entered in the Define Material Properties dialog. If you are considering groundwater in your model, then the material hydraulic properties are entered in the Define Hydraulic Properties dialog. Material properties are assigned to different regions of the model with the Assign properties option.
To read more about the new constitutive models available in RS2 version 9.0, see the Constitutive Modeling article from the Fall 2014 RocNews.
Learn more about each of the different material model aspects below:
- Hoek-Brown (original criterion)
- Generalized Hoek-Brown (latest version)
- Modified Cam-Clay
- Mohr-Coulomb with cap
- Softening/hardening models
- User-defined constitutive model
- Non-linear isotropic elastic model
If you set the Material Type = Elastic, then the material is assumed to have unlimited strength (i.e. it will not yield or fail). The material response will be linear elastic, regardless of the stress magnitude. You may still define strength parameters, but they will only be used for the calculation of strength factor (i.e. degree of overstress).
If you set the Material Type = Plastic, then the material can yield and exhibit non-linear stress-strain behaviour, if the stress exceeds the strength envelope. For Mohr-Coulomb, Hoek-Brown and Drucker-Prager models, you may specify peak and residual strength parameters. Residual strength will be applied if the peak strength is exceeded. If residual = peak, this defines an elastic-perfectly plastic material. If residual strength = 0 this defines a brittle material.
- Tranversely Isotropic
- Duncan-Chang Hyperbolic
By default in Phase2, materials are assumed to have Isotropic elastic properties. This means that the elastic properties are not dependent on directionality, and are defined by a single value of Young's modulus and a single value of Poisson's ratio.
From the parameter calculator dialog, assist dialogs are available to help with the selection of values for UCS, GSI, mi and D. These are accessed by selecting the Pick button beside the input parameter edit box.