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04 - Search Limits

1.0 Introduction

In RocSlope, Search Limits can be used to constrain the search region during Compute Blocks. This can be done by either including specified volumes of interest and/or excluding specified volumes to prevent blocks from forming in unwanted regions of the model.

Finished Product

The finished product of this tutorial can be found in the Search Limits - auto limit.rocslope_model, Search Limits - box limit.rocslope_model, and Search Limits - arbitrary volume limit.rocslope_model files. All tutorial files installed with RocSlope can be accessed by selecting File > Recent Folders > Tutorials Folder from the RocSlope main menu.

2.0 Opening the Starting File

  1. Select File > Recent > Tutorials Folder in the menu.
  2. Go to the Search Limits folder and open the file Search Limits - starting file.rocslope_model.

This model already has the following defined and provides a good starting point to start defining search limits:

  • Project Settings
  • Material Properties
  • External Geometry
  • Joint Properties
  • Measured Joints

In the starting model, Measured Joints are defined over the west and northeast extents of open pit.

3d view of measured joints
3D View of Measured Joints over the West and Northeast extents of the Open Pit

For this tutorial, we will apply different types of Search Limits to constrain the blocks formed to specific regions of the open pit. In RocSlope, there are three types of Search Limits:

  1. Box Search Limits
  2. Arbitrary Volume Search Limits
  3. Auto Search Limits

Additionally, there are two types of constraints that can be applied on a Search Limit:

  1. Completely Inside – blocks admitted during the compute must be completely inside the defined region.
  2. Completely Outside – no part of the blocks admitted during the compute shall be inside or touch the defined region.

2.1 Project Settings

Review the Project Settings.

  1. Select Analysis > Project Settings project settings icon
  2. Select the Units tab. Ensure Units are Metric, stress as MPa.
    project settings units tab
    Units tab in Project Settings dialog
  3. Select the Analysis tab.
    1. Ensure Design Factor of Safety = 1.2.
    2. Ensure Successive Failure is OFF.
      project settings analysis tab
      Analysis tab in Project Settings dialog
  4. Click Cancel to exit the dialog.

2.2 Material Properties

Review the Material Properties.

  1. Select Materials > Define Materials define materials icon. Two (2) material properties are already defined.
  2. The Schist material property has:
    1. Unit Weight = 0.026 MN/m3.
    2. No Water Surface applied.​
      schist material property
      Schist Material Property in Define Materials dialog
  3. The Shale material property has:
    1. Unit Weight = 0.0265 MN/m3.
    2. No Water Surface applied.
      shale material property
      Shale Material Property in Define Materials dialog
  4. Click Cancel to exit the dialog.

2.3 External Geometry

The External is of a pit shell and composed of three volumes. The lower volume (Open Pit Surface.Default.Mesh_extruded_1) is assigned with the Schist material property. The upper volumes (Open Pit Surface.Default.Mesh_extruded_2, Open Pit Surface.Default.Mesh_extruded_3) are assigned with the Shale material property.

2.4 Joint Properties

Review the Joint Properties.

  1. Select Joints > Define Joint Properties define joint properties icon. Two (2) joint properties are defined.
  2. The Smooth joint property has:
    1. Strength Type = Mohr-Coulomb
    2. Cohesion = 0 MPa
    3. Phi = 10 degrees
    4. Waviness = 0 degrees
      smooth joint property strength tab
      Smooth Joint Property Strength tab in Joint Properties dialog
    5. Water Pressure Method = Dry
      smooth joint water parameters
      Smooth Joint Property Water Parameters tab in Define Joint Properties dialog
  3. The Rough joint property has:
    1. Strength Type = Mohr-Coulomb
    2. Cohesion = 0 MPa
    3. Phi = 30 degrees
    4. Waviness = 0 degrees
    5. Rough joint property Strength tab in Define Joint Properties dialog
      Rough Joint Property Strength tab in Define Joint Properties dialog
    6. Water Pressure Method = Dry
      Rough joint property Water Parameters tab in Define Joint Properties dialog
      Rough Joint Property Water Parameters tab in Define Joint Properties dialog
  4. Click Cancel to exit the dialog.

2.5 Measured Joints

Review the Measured Joints.

  1. Select Joints > Define Measured Joints define measured joints icon
  2. 63 Measured Joints are defined and listed in order of Dip, Dip Direction, X, Y, Z, Radius, and Joint Property.

    Dip Dip Direction X Y Z Radius Joint Property
    17 101 -362 -432 1012 200 Smooth
    10 249 -511 -162 1042 200 Smooth
    19 343 -631 112 1066 200 Smooth
    45 58 -789 -329 1098 200 Smooth
    26 213 -628 60 1066 200 Smooth
    84 351 -516 -421 1043 200 Smooth
    51 162 -339 -320 1008 200 Smooth
    49 178 -253 -309 991 200 Smooth
    77 291 -403 114 1021 200 Smooth
    54 51 -417 -421 1023 200 Smooth
    24 122 -591 -584 1058 200 Smooth
    41 49 -643 -393 1069 200 Smooth
    31 217 -436 -142 1027 200 Smooth
    74 48 -628 -313 1066 200 Smooth
    76 295 -622 -578 1064 200 Smooth
    48 273 -691 -451 1078 200 Smooth
    22 335 -655 -307 1071 200 Smooth
    53 224 -598 -532 1060 200 Smooth
    63 107 -336 -320 1007 200 Smooth
    47 106 -319 -542 1004 200 Smooth
    24 124 -487 143 1037 200 Smooth
    28 226 -632 -556 1066 200 Smooth
    26 330 -730 -363 1086 200 Smooth
    45 216 -333 -517 1007 200 Smooth
    36 221 -321 -473 1004 200 Smooth
    32 216 -667 -565 1073 200 Smooth
    57 101 -342 -147 1008 200 Smooth
    30 312 -305 182 1001 200 Smooth
    74 112 -373 80 1015 200 Smooth
    52 103 -379 -564 1016 200 Smooth
    33 86 -263 160 993 200 Smooth
    42 108 -563 -446 1053 200 Smooth
    36 68 -325 -340 1005 200 Smooth
    43 80 -467 -103 1033 200 Smooth
    40 74 -546 150 1049 200 Smooth
    54 79 -374 -140 1015 200 Smooth
    81 323 -275 82 995 200 Smooth
    45 85 -412 -24 1022 200 Smooth
    15 316 -555 -208 1051 200 Smooth
    90 356 -488 -130 1038 200 Smooth
    81 349 -788 134 1098 200 Smooth
    37 235 -289 40 998 200 Smooth
    29 117 -337 134 1007 200 Smooth
    84 337 -271 -550 994 200 Smooth
    71 79 -532 196 1046 200 Smooth
    66 121 -752 -293 1090 200 Smooth
    32 335 -611 -180 1062 200 Smooth
    50 129 -580 -369 1056 200 Smooth
    57 101 -511 17 1042 200 Smooth
    48 91 -718 73 1084 200 Smooth
    25 125 -528 -60 1046 200 Smooth
    43 80 -466 -251 1033 200 Smooth
    33 73 -366 -575 1013 200 Smooth
    47 65 -452 -90 1030 200 Smooth
    83 336 -694 -588 1079 200 Smooth
    57 101 200 12 1042 200 Rough
    48 60 250 20 1084 200 Rough
    25 125 251 -20 885 200 Smooth
    43 80 350 -30 905 200 Smooth
    33 73 574 -60 964 200 Smooth
    47 65 248 -32 945 200 Smooth
    83 336 300 -27 999 200 Smooth
    81 349 600 -20 959 200 Smooth
    37 235 346 -20 953 200 Smooth
    29 117 577 -60 900 200 Smooth
    84 337 532 -130 894 200 Smooth
    71 79 459 -230 946 200 Smooth
    66 121 383 -200 940 200 Smooth
    68 measured joints defined
    68 Measured Joints defined in Define Measured Joints dialog
  3. Click Cancel to exit the dialog.

3.0 Compute (without Search Limits)

First let's compute blocks without adding any Search Limits.

3.1 Compute Blocks

To compute the blocks:

  1. Navigate to the Compute workflow tab compute workflow tab
  2. Select Analysis > Compute Blocks compute blocks icon

As compute is run, the progress bar reports the compute status. Once compute is finished, the Results node is added to the Visibility Tree and valid blocks are shown in the viewport. The Results node consists of the collection of valid blocks and the socketed slope. The original External and Measured Joints visibility is turned off.

results no search limits
3D View of Valid Blocks computed without Search Limits
A valid block includes any block which is not attached to the "non-terrain" surfaces. The non-terrain surfaces are the sides and bottom of the model, and is automatically determined by RocSlope. In the case of Search Limits, a valid block must be fully inside any Completely Inside Search Limits and full outside any Completely Outside Search Limits.

Without any Search Limits defined, the entire External and all Joints are considered when computing blocks.

For models with large External and many Joints, computing the entire External and all Joints can be resource-intensive. Consider using Search Limits to narrow down the compute region.

4.0 Auto Search Limits

The Auto Search Limits option in RocSlope automatically determines the regions of interest based on where joints are clustered. The logic behind Auto Search Limits is that if a single joint or joint from a cluster of joints can daylight on the external, then it has the potential of forming blocks which can daylight over that region.

To compute the Auto Search Limits:

  1. Select Analysis > Search Limits > Auto Search Limits search limit icon
  2. Two Search Limits are automatically added to the model:
    • Auto Limit 1 contains the XY and bottom extents of the joints from the west joint cluster, and top extents of the External geology.
    • Auto Limit 2 contains the XY and bottom extents of the joints from the east joint cluster, and top extents of the External geology.
auto search limits
3D View of two Auto Search Limits around the two Measured Joint clusters

Auto Limits are volumetric search regions where any blocks inside (but not touching) the search volume is considered valid.

5.0 Compute (with Auto Search Limits)

Now let's compute blocks with the Auto Search Limits.

5.1 Compute Blocks

  1. Ensure you are still in the Compute workflow tab compute workflow tab
  2. Select Analysis > Compute Blocks compute blocks icon

The same set of block results as before is computed since all regions with joints are being considered.

CAD 3D view showing all valid blocks computed within the two auto search limits
CAD 3D view showing all valid blocks computed within the two auto search limits

Now, delete the Auto Search Limits:

  1. Select Auto Limit 1 node from the Visibility Tree.
  2. Click the Delete delete icon button.
  3. Select Auto Limit 2 node from the Visibility Tree.
  4. Click the Delete delete icon button.

6.0 Add Search Limit By Box

If we wanted to only consider the southwest region, we could reduce the valid search region by adding a Box as the search region.

To add a box search limit:

  1. Select Analysis > Search Limits > Add Search Limit by Box add search limit by box icon
  2. The Create Search Limit Area dialog allows the user to define the extents of the Box Search Limit.
    1. Set Defined By = 2 Corners.
    2. Set the Box Corners:
      • First Corner X = -800, Y = -600, Z = 500.
      • Second Corner X = -100, Y = -100, Z = 1300.
        create search limit dialog
        Create Search Limit Area dialog
    3. Click OK.
  3. In the Slope Limit dialog:
    1. Set Name = Search Limit 1.
    2. Set Search Limit Type = Completely Inside.
    3. Select Blocks on non-terrain surface are considered invalid.
    4. slope limit dialog
      Slope Limit dialog
      The non-terrain surface includes the bottom and sides of the model and are automatically determined by RocSlope. Any blocks touching the non-terrain surface is considered invalid to prevent blocks from coming out of the bottom and side of the model. For some slope geometries such as vertical or overhanging sides of the models which should actually be considered as a valid daylighting surface, the non-terrain surface may not be automatically determined as the user intended. In such rare cases, a Search Limit Type with Completely Inside and Blocks on non-terrain surface are considered invalid unselected can be used to override the non-terrain surface. Any blocks which are completely contained by the Search Limit (even if attached to the non-terrain) will be considered valid.
  4. Click OK to add the Search Limit.

Search Limit 1 has been added to the model.

3d view of user-define search limit
3D View of user-defined Box Search Limit of the type 'Completely Inside'

7.0 Compute (with Completely Inside Box Search Limit)

Now let's compute blocks with the user-defined Box Search Limit.

7.1 Compute Blocks

  1. Ensure you are still in the Compute workflow tab compute workflow tab
  2. Select Analysis > Compute Blocks compute blocks icon

Only blocks fully contained in Search Limit 1 are being considered.

3D CAD view showing valid blocks computed within a completely inside box volume search limit
3D View showing Valid Blocks computed within a Completely Inside Box Search Limit

    8.0 Add Search Limit By Arbitrary Volume

    If we wanted to exclude a sub region contained inside Search Limit 1, we can add another Search Limit which overlaps a portion of Search Limit 1. For example, if we wanted to compute blocks in the southwest region, but excluding anything in the Schist material region of the open pit:

    1. Select the External piece with Applied Property = Schist from the Visibility Tree (i.e., Open Pit Surface.Default.Mesh_extruded_1).
    2. Select Analysis > Search Limits > Add Search Limits by Arbitrary Volume search limits icon
    3. In the Slope Limit By Entity dialog:
      1. Set Name = Search Limits 2.
      2. Set Search Limit Type = Completely Outside.
        slope limit by entity dialog
        Slope Limit by Entity dialog
      3. Click OK to add the Search Limit.

    Search Limits 2 has been added to the model.

    3D CAD view showing a completely inside box search limit and and a completely outside arbitrary volume search limit
    3D view showing a Completely Inside Box Search Limit and and a Completely Outside Arbitrary Volume Search Limit

    9.0 Compute Blocks (with Arbitrary Volume Search Limit)

    Now let's compute blocks with the user-defined Arbitrary Volume Search Limit.

    1. Ensure you are still in the Compute workflow tab compute workflow tab
    2. Select Analysis > Compute Blocks compute blocks icon

    Only blocks which are inside Search Limit 1 but outside Search Limits 2 are being considered.

    3D CAD view showing all valid blocks inside Search Limit 1, but outside Search Limits 2
    3D View showing all Valid Blocks inside Search Limit 1, but outside Search Limits 2

    This concludes Tutorial 04.

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