ID_PLOT_STRESS_INPLANESHEAR   Plot > Stress > τip   In-Plane Shear Stress

ID_PLOT_STRESS_INPLANENORMAL   Plot > Stress > σip   In-Plane Normal Stress

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This allows you to contour the maximum shear stress ID_PLOT_STRESS_INPLANESHEAR acting on the grid plane, and the stress component normal ID_PLOT_STRESS_INPLANENORMAL to the grid plane or parallel to a line grid.

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

 

clip0288

 

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 clip0290 button on the Contours toolbar activates the Stress Components toolbar.

 

clip0291

 

To calculate the in-plane stresses, the stress state at each point on the grid plane is reoriented to determine the maximum shear stress parallel to the grid plane and the stress normal to the plane. Note that σip is oriented normal to the grid plane and parallel to the direction of a line grid.

 

dip direction is measured positive clockwise from the y-axis.

dip of the plane is measured positive down from the horizontal (i.e. the dip direction).

plunge of the normal is measured positive down (i.e. negative up) from the horizontal.

 

In elastic analysis, the maximum in-plane shear stress is normally used with the in-plane normal stress and the Mohr-Coulomb strength criterion

 

ID_PLOT_MODIFY_IP Plot > Strength Factors > In-plane Parameters

 

to estimate the amount of slip due to over-stressing, on a fault, joint set or bedding plane oriented in the same way as the grid plane. Since these parameters are orientation dependant, this criterion is representative for anisotropic 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 DD planes

Fault-Gouge in DD planes

Backfill-Hyperbolic in DD planes.

 

Over-stressing can be presented in several forms including:

 

ID_PLOT_FC_D ID_PLOT_FC_D_INV Plot > Strength Factors > SF-ip   Strength/Stress

ID_PLOT_EXCESS_INPLANE Plot > Strength Factors > dTip   Excess Shear Stress

 

The contour range is set using

 

ID_RANGE Plot > Range

 

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

 

ID_VIEW_BAR_OPTIONS Tools > Configure Contouring Toolbar > Stress

 

The user may find it handy to add the

 

ID_PLOT_STRESS_SPECIAL More Stress Components

 

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

 

Related topics:

 

ID_PLOT_STRESS_INPLANEMAX Plot > Stress > S1i   In-plane Maximum

ID_PLOT_STRESS_INPLANEMIN Plot > Stress > S3i   In-plane Minimum

ID_PLOT_STRESS_UBSHEAR Plot > Stress > Tub   Ubiquitous-plane Shear

ID_PLOT_STRESS_UBNORMAL Plot > Stress > Sub   Ubiquitous-plane Normal