ID_PLOT_FC_E   Plot > Strength Factors > SF-ub   Strength/Stress

ID_PLOT_FC_E_INV   Plot > Strength Factors > SF/ub   Stress/Strength

ID_PLOT_EXCESS_UB   Plot > Strength Factors > Δτub   Excess Stress

ID_PLOT_NTUB   Plot > Strength Factors > N(Δτub/std)   Probability

UB#  Plot > Strength Factors > UB#

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Contours the strength for ubiquitous-plane shear.

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

 

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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 clip0306 button on the Contours toolbar activates the Strength Factor Components toolbar.

 

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To calculate the ubiquitous shear and normal stresses, the stress state at each point on the grid plane is reoriented to determine the maximum shear stress parallel to the ubiquitous shear plane and the stress normal to the ubiquitous shear plane.

 

 

The orientation of the ubiquitous shear plane is set using

 

ID_PLOT_MODIFY_UB Plot > Strength Factors > Ubiquitous Parameters

 

In elastic analysis the maximum ubiquitous-plane shear and normal stress can be used with the Mohr-Coulomb strength criterion to estimate the amount of slip due to over-stressing, on a fault, joint set or bedding plane at the specified orientation. 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

 

Here we assume that the stress path to failure takes place by increasing tub without loosing confinement.

 

ID_PLOT_FC_E SF-ub Strength/Stress   can be determined as [ Cohesion + σub tan(φ) ] / τub

ID_PLOT_FC_E_INV SF-ub Stress/Strength   can be determined as τub / [ Cohesion + σub tan(φ) ]

ID_PLOT_EXCESS_UB dTub Excess   can be determined as Δτub = τub - [ Cohesion + σub tan(φ) ]

ID_PLOT_NTUB NTub Probability   can be determined as N(Δτub /std)

 

 

Strength parameters are set up using

 

ID_PLOT_MODIFY_UB Plot > Strength Factors > Ubiquitous Parameters

 

Related topics:

 

ID_PLOT_STRESS_UBSHEAR Plot > Stress > Tub - Ubiquitous-plane Shear

 

ID_PLOT_STRESS_UBNORMAL Plot > Stress > Sub - Ubiquitous-plane Normal

 

ID_PLOT_STRESS_UBMAX Plot > Stress > S1u - Ubiquitous-plane Maximum

 

ID_PLOT_STRESS_UBMIN Plot > Stress > S3u - Ubiquitous-plane Minimum

 

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

 

ID_PLOT_EXCESS_INPLANE Plot > Strength Factors > dTip Excess

 

ID_PLOT_EXCESS_SINPLANE Plot > Strength Factors > dSip Excess

 

ID_PLOT_NTIP Plot > Strength Factors > NTip Probability

 

UB#2 & UB#3 – activates strength parameters for ubiquitous plane #2 and/or #3. When checked, the minimum for all active ubiquitous planes is presented for all strength parameters (ID_PLOT_NTUB Plot > Strength Factor > Probability N-distribution, ID_PLOT_FC_E ID_PLOT_FC_E_INV Plot > Strength Factors > SF-ub - Stress/Strength and ID_PLOT_EXCESS_UB Plot > Strength Factors > dTub - Excess Stress). To determine which ubiquitous plane has the minimum strength you can plot ID_PLOT_EXCESS_INPLANE Plot > Strength Factors > UB# with minimum strength) or left click on and strength parameter plot.