| 1. |
The program is not behaving correctly. It
either doesn't start, crashes all the time, or doesn't work
as defined in the manual. What's wrong?
If you are getting an error message and you're running an older
operating system (Windows 9x/NT), there is likely 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 - it's up to you to update
your operating system software. This problem can be easily fixed
by downloading the latest Microsoft system file updater from
our website: http://www.rocscience.com/anon/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.
Remember that it is always advisable to make a backup before
installing software that modifies system files.
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| 2. |
To get reasonably accurate results, what
sort of element density is required?
The results are accurate right up to the surface of the excavation.
But the results are a function of the discretization of the
mesh and vary depending on the complexity of the induced stress
field. In some cases a coarse mesh can be acceptable, while
in others it isn't. The only way to tell is to fine up the mesh.
You can do this very easily in Examine3D by using the
Subdiv. Elem/Poly option in the Object Tools and selecting a
group of elements with a box to subdivide, then comparing the
results from two analyses.
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| 3. |
Does Examine3D handle surface
excavations?
Yes, Examine3D handles surface excavations.
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| 4. |
Is there a limit to the integer or real
ranges that Examine3D can accept?
The Examine3D modeler has 5-6 digits of precision.
If your coordinates exceed this precision, translate your model
to the origin before working on it.
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| 5. |
How do I check tractions?
The safest way to check is to use an ASCII editor and look directly
at the ex3 file. Everything is commented and you should see
the numbers that you want to verify. The traction conditions
can also be verified using the Shade-Shade-Options-Normals-Pressure
option then quickshade the model. The components are colored
a bluish color. The magnitude can be verified by looking at
the file.
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| 6. |
Does Examine3D support the change
of element colors when reading and writing to files?
Currently Examine3D does not support the change of
color at the element level when reading and writing files. It
does however support the change of color at the component and
object level.
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| 7. |
Can Examine3D work under a Windows
NT environment?
Yes. We actually develop the software under Windows NT 4.0.
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| 8. |
Can the input file and result file from
MAP3D be imported into Examine3D?
No, we currently do not have the ability to read MAP3D files.
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| 9. |
Can AutoCAD drawings be imported into Examine3D
?
Examine3D constructs excavation geometry by using skinning
and extrusion technology between mine sections. These sections
can be imported from AutoCAD. We suggest that users construct
the mesh inside the Examine3D modeler but the program
will read edge-connected 3DFACES from AutoCAD.
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| 10. |
What is the software limitation with respect
to the number of blocks and the number of mining steps that
could be included in a given model? What are the limitations
on number of nodes and elements?
Each file contains one mining step. The user must construct
a number of files to simulate the excavation sequence. There
are capabilities in the program for looking at differential
stresses, displacements, and energy, between files. There is
no limitation as to the number of elements used to construct
your boundary element mesh. There's no built in limitation to
the number of elements or nodes that can be solved. In the past,
there was a difficulty with versions prior to 4.098, where the
maximum file size in MS Windows (2GB) caused problems with the
swap file thus limiting the maximum number of nodes to ~7500.
This has since been fixed, so be sure you have the latest update
from our website. You must also have adequate hard disk space
to solve these large models, so in fact you are limited by the
size of your hard disk. Use the Compute3d Stats option in the
Analysis Param menu to see the size needed to solve the model.
To calculate the required amount of disk space you can also
use the following equation: D = N*N*9*4 - where,
D = Disk space required
in Bytes.
N = Number of Nodes in your
problem. This is the number displayed in the lower right corner
of the Modeler window beside the ND:
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| 11. |
Can Rocscience customize the software for
my needs?
Rocscience software is built to meet customer requirements.
We're happy to incorporate your feedback into future versions.
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| 12. |
Can seismic event location, magnitude and
source parameters be imported into the model?
Yes, complete support for the visualization of 3D seismic datasets
exists. The program can be used to visualize any special data
in conjunction with the stress analysis results.
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| 13. |
Is it possible to apply tractions (i.e.
internal pressures) to specific elements in my model?
Yes, it is possible to apply tractions to excavation element
surfaces.
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| 14. |
Is it possible to apply liners (beam elements),
bolts and cables?
Examine3D does not handle beams and bolts.
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| 15. |
What procedure is used for forming excavation
geometry?
Excavation geometry is constructed in the modeler through use
of skin polylines and extrusions.
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| 16. |
In Examine3D, can different
boundary (primary) stresses be applied in x- y-and z-directions?
Yes, different boundary tractions can be applied to individual
elements in any direction you want.
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| 17. |
Can a model created by Examine3D
version 3.0 be read into Examine3D version 4.0?
Models created with version 2 and 3 of Examine3D are
fully supported by version 4.
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| 18. |
Can I use symmetry?
Symmetry is not supported in Examine3D.
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| 19. |
How can DXF file entities be imported?
The DXF import is handled through a utility called dxfgeo found
in the utilities folder in the Examine3D installation
directory. There is documentation in this folder. The program
is a Command line program and should be run from a DOS prompt.
The documentation contains the type of entities supported. The
program converts AutoCAD DXF files to Examine3D GEO
files that you can import into the program. Geo files are discussed
in the manual and used in the tutorial section.
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| 20. |
What boundary element formulation does Examine3D
utilize (FF, DD or both)?
Examine3D currently uses the Direct Boundary Element method.
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| 21. |
Is it necessary to use a staged approach
to model the mining of complex 3D excavations?
Since Examine3D uses a linear elastic material model,
there is no dependence on the loading path. Therefore, for a
staged analysis, the stresses in the final stage are independent
of how you take out the material in prior stages.
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| 22. |
Does the "stress path" or the "loading path"
of the rock have to be modeled to reasonably represent the stresses
induced in the rock mass remaining around the excavations?
The stresses are really only influenced by the current excavation
geometry and the stress field. Only programs with yielding material
models (plasticity) such as Phase2 account for the stress path.
In short, to do a staged excavation in Examine3D you
must look at the geometry of each stage independently.
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| 23. |
Is there a restriction on the file size
or the number of nodes in Examine3D?
There are no built in limits on the number of nodes or elements
that Examine3D can handle. The number of nodes that
can be processed is limited by the amount of disk space you
have available. In order to Compute the boundary element matrix
you require N*N*9*4 bytes of disk space where N is the number
of nodes. The program needs this space to swap the matrix to
disk. For example, a 3000 node problem would require 324 MB
of disk space to solve.
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| 24. |
Is it possible to import a model file in
DXF format that has been written by Vulcan or Envisage?
As long as the file format is DXF, you should be able to import
it into Examine3D.
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| 25. |
Can Examine3D tabulate the stresses at different
locations so that it can be manipulated in a spreadsheet or
similar application?
Write a portable data file (.DAT file) using the File-Save File
option in the Interpreter. Edit the file using an editor (notepad,
wordpad, word etc) and remove the header information so that
all you are left with is the raw NUE (xyz) data. Bring this
new file into excel as a space delimited file.
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| 26. |
How are the ubiquitous joints implemented
in Examine3D ?
The ubiquitous joints in Examine3D are a post-processing
facility. The joints are not explicitly modeled and do not effect
the stress field. The Interpreter uses the defined orientation
and strength properties of the joint to determine whether a
joint would slip if it existed at every point that stresses
are sampled (thus the term ubiquitous). The joints have an effect
on the strength factor but not the stresses or displacements.
Please refer to the Examine3D manual. The program takes
a joint, calculates the factor of safety against slip, and compares
this to the rock mass factor of safety. The minimum of these
is used.
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| 27. |
How is data data visualization in the Interpreter
done in Examine3D?
The following PDF document describes the data visualization
algorithms implemented in Examine3D.
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| 28. |
Is Examine3D suitable for the
analysis of near surface excavation ?
Examine3D can be used for near surface excavations. However
to ensure the
proper modeling and analysis of results, the following should
be kept in
mind: 1. The extent of the surface is extremely important.
Models done by both
customers and Rocscience indicate that the extent of the surface
should
range between 10 and 50 typical diameters. A typical diameter
would be the
maximum dimension of a box placed around your zone of interest.
The best way
to ensure you have gone out far enough is to vary the extents
of the surface
until there is no practical change in the results.
2. Non-horizontal ground surfaces must be analyzed with a
two step process
if you are interested in displacements. The first step is
modeling of just
the ground surface. The second step is modeling the excavations
with the
ground surface. To see the displacements due to the excavation
only, you
must then use the dstress utility to subtract the displacements
from the
first step. This process is necessary for non-horizontal ground
surfaces
because there are displacements in the first step due to elastic
rebound or
settlement (depending on where the defined ground surface
elevation for
initial gravitational stresses is with reference to the ground
surface
boundary elements), and you generally want to factor these
displacements out
of the analysis. If you are just interested in stresses, this
process is not
necessary.
3. Examine3D has a isotropic single material, elastic
material model. All
the assumptions which go with this statement apply.
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