4 - Search Limits

1.0 Introduction

In RocSlope3, 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 products of this tutorial - Tutorial 04 Search Limits - auto limit.rocslope_model, Tutorial 04 Search Limits - box limit.rocslope_model, and Tutorial 04 Search Limits - arbitrary volume limit.rocslope_model - can be found in the Tutorial 04 Search Limits folder. All tutorial files installed with RocSlope3 can be accessed by selecting File > Recent Folders > Tutorials Folder from the RocSlope3 main menu.

2.0 Opening the Starting File

1. Select File > Recent > Tutorials Folder in the menu.
2. Go to the Tutorial 04 Search Limits folder and open the file Tutorial 04 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.

For this tutorial, we will apply different types of Search Limits to constrain the blocks formed to specific regions of the open pit. In RocSlope3, 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
2. Select the Units tab. Ensure Units are Metric, stress as MPa.
   
3. Select the Analysis tab.
   1. Ensure Design Factor of Safety = 1.2.
   2. Ensure Successive Failure is OFF.
   3. Ensure Combined blocks is OFF.
      
4. Click Cancel to exit the dialog.

2.2 Material Properties

Review the Material Properties.

1. Select Materials > Define Materials . 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.​
      
3. The Shale material property has:
   1. Unit Weight = 0.0265 MN/m3.
   2. No Water Surface applied.
      
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 . 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
      
   5. Water Pressure Method = Dry
      
3. The Rough joint property has:
   1. Strength Type = Mohr-Coulomb
   2. Cohesion = 0 MPa
   3. Phi = 30 degrees
   4. Waviness = 0 degrees

      

   5. Water Pressure Method = Dry
      
4. Click Cancel to exit the dialog.

2.5 Measured Joints

Review the Measured Joints.

1. Select Joints > Define Measured Joints

   

   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

   

2. Click Cancel to exit the dialog.

3.0 Compute (without Search Limits)

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

3.1 Compute Blocks

To compute the unit blocks:

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

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 unit blocks are shown in the viewport. The Results node consists of the collection of valid unit blocks and the socketed slope. The original External and Measured Joints visibility is turned off.

Without any Search Limits defined, the entire External and all Joints are considered when computing unit 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 RocSlope3 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
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 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 unit blocks with the Auto Search Limits.

5.1 Compute Blocks

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

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

Now, delete the Auto Search Limits:

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

      

      The non-terrain surface includes the bottom and sides of the model and are automatically determined by RocSlope3. Any blocks (unit or combined) 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.

7.0 Compute (with Completely Inside Box Search Limit)

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

7.1 Compute Blocks

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

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

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
3. In the Slope Limit By Entity dialog:
   1. Set Name = Search Limits 2.
   2. Set Search Limit Type = Completely Outside.
      
   3. Click OK to add the Search Limit.

Search Limits 2 has been added to the model.

9.0 Compute Blocks (with Arbitrary Volume Search Limit)

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

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

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

This concludes Tutorial 04.