Plot > Stress > σ1   Major Principal Stress

  Plot > Stress > σ2   Intermediate Principal Stress

  Plot > Stress > σ3   Minor Principal Stress

This allows you to principal stress components σ1 σ2 σ3.

These components can be accessed via the Stress Components toolbar as follows:

This toolbar can be changed to a vertical orientation by dragging is against either the right or left hand edge of the main window.

It can be changed back to a horizontal orientation by dragging is against either the top or bottom edge of the main window.

Selecting the button on the Contours toolbar activates the Stress Components toolbar.

In elastic analysis, the major principal stress is normally used with the minor principal stress and the Mohr-Coulomb or Hoek-Brown strength criterion

Plot > Strength Factors > Strength Parameters

to estimate the amount of damage in the rockmass due to over-stressing. Since none of the parameters have any orientation sensitivity, this criterion is representative for homogeneous rock mass stability.

By contrast, in non-linear analysis the stresses can never exceed the strength unless some creep is used. In this latter case, viscous creep can allow stress states above the failure criterion, thus indicating a lack of static equilibrium. Hence for non-linear analysis one normally directly considers the amount of non-linear strain or the strain rate predicted by the model

Mohr-Coulomb in 3D FF blocks.

Over-stressing can be presented in several forms including:

Plot > Strength Factor > SF-A   Strength/Stress

Plot > Strength Factor > SF-B   Strength/Stress

Plot > Strength Factors > SF-C   Strength/Stress

Plot > Strength Factors > dS1   Excess Stress

Plot > Strength Factors > dTmax   Excess Stress

The contour range is set using

Plot > Range

Any of these components can be added to the contouring toolbar if desired

Tools > Configure Contouring Toolbar > Stress

The user may find it handy to add the

More Stress Components

button to the contouring toolbar for quick access to all stress components.

The intermediate principal stress is normally used in the calculation of the octahedral shear stress

Plot > Stress > Toct   Octahedral shear Stress

or the mean stress

Plot > Stress > Smean   Mean Stress.