Material Behavior
The corresponding chapter of Theoretical Background provides an overview of the properties of the Hoek-BROWN model.
Input dialog box
By setting the material model to Hook of Steel, the dialog box for defining the material properties has two additional tabs, as highlighted in the image below.
Isotropic tab | Rock | Plastic| Hook‑Brown
In this tab, the input parameters required for the representation of the material behavior are defined.
- σi - Uniaxial compressive strength of intact rock (UCS)
- mb - Material parameter for the massif
- s - constant
- a - constant
- E - Modulus of elasticity
- ν - Poisson's ratio
The modulus of elasticity and Poisson's ratio have to be defined in the "General" tab, which is shown in the superordinate chapter Input - Soil Materials.
The material constants mb, s, and a can be defined in two ways, either directly or indirectly via the corresponding GSI values. The corresponding selection is available under Failed surface parameters.
Empirical values
The input dialog box for selecting empirical values appears as shown in the figure below.
All material parameters can be entered directly in the dialog box. Since they are related to the Geological Strength Index and the relaxation factor, they can alternatively be described using the GSI values.
GSI values
The input dialog box for the GSI values is displayed as shown in the figure below.
The input of the following values is required.
- mi - Material parameter for the massif
- D - Restoration factor or failure
- GSI - Geological Strength Index
Internally, they are converted into Material Parameters of Hook-rown Failure Criterion Converted.