Below you will find answers to some Frequently Asked Questions (FAQs) for Swedge. If you cannot find an answer to your question or problem after reading the FAQs:
Try the Search feature on this Help system.
Contact Rocscience technical support at techsupport@rocscience.com.
FAQs
(click on the question to read the answer)
If you are getting errors and you're running an older operating system (Windows 9x/NT), then the reason is most likely to do with an incompatibility between Rocscience software and older operating system files. Rocscience software requires up to date operating system files in order to run properly. As a rule, Rocscience does NOT change or alter your operating system files and puts the onus on you to maintain up to date operating system software.
This problem can easily be fixed by downloading the latest Microsoft system file updater from our website: http://www.rocscience.com/downloads/general/vcredist.exe
Download the file by clicking on the above link. Save the vcredist.exe file to your computer and then run it. Follow the directions.
Note: It is always advisable to make a backup before installing software that modifies system files.
The program requires that the computer's graphics card has support for OpenGL for the visualization of the three-dimensional geometry. The most common reason for the improper display of the wedge geometry or crashing of the program while trying to view the three-dimensional geometry, is an incompatibility with the graphics card (display adapter) and its support for OpenGL. If your graphics card does not support OpenGL (most do), the program will not work, so check with your graphics card manufacturer to make sure that your card supports OpenGL. Also, if the graphics card driver is old and has bugs with its OpenGL driver, then the program will have problems. Go to the website of your graphics card manufacturer and make sure you have the latest driver for your graphics card.
There are two possible reasons for this. The first reason is handled in FAQ#2 and should be reviewed first. If this does not fix the problem then the second possible reason is the color mode for your display settings. Swedge has problems with a Colors setting above 24 bit color (i.e. 32 bit color) on certain display adapters and computers (e.g. IBM Thinkpad). To check this, go to your control panel and pick the Display option. Choose the Settings tab and look at the Colors setting. This should not read 32 bit in any part of the description. Try setting the number of colors to a lesser value (i.e. 24, 16 bit, High Color) and trying Swedge.
Sounds like a driver problem with your video card. Have you checked your video card manufacturer for their latest driver? You can also try deleting the opengl32.dll and glu32.dll files in the Swedge installation folder (make a backup of them first). If the program doesn't run without these files, copy them back. Try another machine with win98/NT or 2000. Although we have tested the program under win95 we obviously can not try every possible hardware configuration. Another thing you can try is turning off the double buffering. You do this by starting a new model, going into Display Options in the View menu, toggling off the double-buffering check box, click apply and then OK. Exit the program and start it up again. Do you see the wedge view now?
Note: Under Windows 2000, the opengl files (opengl32.dll and glu32.dll) supplied with Swedge version 3.xx are incompatible. Deleting these files from the Swedge installation folder should solve most problems since Windows 2000 is shipped with opengl.
Use the External Force option in the Forces tab of the Input Data Dialog. With this you can define a single force and its direction equivalent to the hydrostatic force.
Here are some things to try:
Go to the Swedge installation folder and delete the files glu32.dll and opengl32.dll. Restart your machine and try running Swedge. If this doesn't fix it, your problem is most likely with your graphics card and its OpenGL support. What graphics card do you have? Check their website for a driver update.
Is Swedge useful for rock slopes with irregular shapes?
There are restrictions on the slope geometry. The slope geometry is composed of two planes of arbitrary orientation. One plane is the face of the slope and the other is the top.
Is it possible to search for unstable blocks from a huge number of wedge type blocks?
Yes. Probabilistic analysis is handled.
Do you have any technical papers using Swedge?
The reference for the method is:
"Rock Slope Engineering" (Rev. 3rd edition, E. Hoek & J.W. Bray, pp 341-351).
No, Swedge version 2.0 does not include seismic forces.
Seismic forces can be modeled in Swedge version 3.0 and 4.0.
Swedge computes average water pressures assuming that the pressure is always zero at the free faces (per page 8 in the manual). In the event that a pit lake develops after closure, this is no longer the case. What recommendations would you make for analyzing a wedge that daylights below the surface of a pit lake that has inundated a portion of the pit slope?
Determine what the average pressure should be for your geometry (see answer to next question) then adjust the unit weight of water to simulate this. You could also turn off water pressure and use a single external load that's equal to the resultant water force.
In the case of no tension crack, the maximum water pressure (b) is located half way down the line of intersection and has a value of b=gammaw*Hw/2. The actual pressure distribution on each face is a tetrahedron with volume Ab/3 where A is the face area of the slip plane and b is the maximum water pressure. The average water pressure is just the volume divided by the surface area or b/3. Substituting the value of b from above gives the equation in the manual. The same logic can be used for the case of a tension crack.
This was a bug which has been fixed in the latest version of Swedge.
You most likely have the water pressure turned on. Go to the Forces tab in the Deterministic Input Data dialog and uncheck the water forces. The water forces exceed the normal force caused by the wedge. This is why the factor of safety is 0 (no normal force).
Joint set 1: Dip Angle = 87.1, Dip Direction = 195.1, Cohesion = 5 t/m^2, Friction = 30º.
Joint set 2: Dip Angle = 83.0, Dip Direction = 116.7, Cohesion = 5 t/m^2, Friction = 30º.
Slope Face: Dip Angle = 90.0, Dip Direction = 120, Height is 25 m.
Upper Face: Dip Angle = 0.0, Dip Direction = 120.
Unit Weight = 3 t/m^3.
No tension crack, seismic loading or external forces.
There is no direct support for Rockworks files, however you could probably cut and paste the data into Dips 5.0 and then export a file to Swedge.
For joint water pressure, are there other options besides "wet (fully saturated)" or "dry" options?
Dry and fully saturated are the only conditions handled in Swedge version 3.0. It is possible to do partially saturated but this requires adjusting the unit weight of water.
In Swedge version 4.0 you may specify a percentage filled water level, or a custom pressure on each plane of the wedge.
Yes, the location of the tension crack can be user-defined, by specifying a trace length. The trace length is the distance of the tension crack from the crest, measured along the trace of plane 1 on the Upper Slope Face.
See the Overview of Swedge Input Data for a figure which illustrates the tension crack trace length.
Can we perform Wedge Analysis in Earthquake Conditions (e.g. pseudo-static methods?) using Swedge?
Yes. In the Input Data dialog, select the Forces tab and select the Seismic checkbox.
You can specify a seismic coefficient, and the direction in which the seismic force is to be applied.
In Swedge version 3.0, only the Active model is used, by default, for all bolts.
In Swedge version 4.0, you may specify either Active or Passive bolts.
For a discussion of Active and Passive bolt models, see the Help topic: How Bolts are Implemented in Swedge.
Also see Evert Hoek's "Rock Slope Engineering" (Appendix 1) for the equations used.
Here are Evert Hoek's comments on the use of an Active or Passive bolt model in Swedge. He made these comments after he was asked whether a Passive model in Swedge would be useful and how it should be implemented:
This is a limit equilibrium analysis and so, for the moment, forget about everything else and think about the limit state. At the point of failure a tensioned rockbolt or a grouted dowel will be tensioned to their limit and all forces will be mobilized - both the upward restraining force and the normal forces across the surfaces. At this stage the rockbolt or dowel does not care how it got there and so the pretension or lack thereof is not an issue. Now we go back and look at the loading history. For a pretensioned rockbolt it is true that the forces applied to the rock are those of the pretensioning load and both the upward restraining force and the normal forces are active. In the case of an untensioned grouted dowel or cable, the restraining force is mobilized once the block displaces but, depending upon the sequence of installation (it is quite common to pre-reinforce rock slopes with untensioned grouted dowels), this displacement could be very small and I see no reason why you would discount the normal force generating the frictional resistance. The only distinction that a purist could make is that, because an untensioned grouted dowel permits greater displacement, one may consider using the residual shear strength of the rock surfaces rather than the peak strength that could be assumed for a pre-tensioned rockbolt or cable.
In practice rockbolts come in 20 ton steps and, for larges slopes, cables tend to come in 50 or 100 ton steps. Hence, too refined an approach is redundant. I recommend that you stay with the original model and just put in the ultimate capacity of the reinforcement and allow it to activate both the upward resisting force and the normal forces across the planes. From a practical point of view, I do not see the need for different rockbolt and dowel models.
I think it's up to you whether you use the current bolt model or not, I would. The program's Infoviewer contains all the information necessary for you to do some simple hand calculations with whatever model you consider appropriate. I think you might find that with a passive model, where you add the bolt force to the restraining forces and possibly ignore the increase in frictional resistance, you will require more support $$$. You better be sure.