RS3 Quick Start

1.0 Introduction

This tutorial introduces some of the basic features of RS3. The model used in this tutorial analyzes the effect of a foundation being constructed near a sloped underground tunnel. We will create a multi-stage model using stages so that we may observe how the soil behaves at each specific step of the foundation's construction and compare the results. The stages that will be considered are:

Initial Conditions
Excavate Tunnel
Excavate Foundation
Pour Concrete Foundation
Loading Foundation

All tutorial files installed with RS3 can be accessed by selecting File > Recent > Tutorials folder from the RS3 main menu. The finished product of this tutorial can be found in the Quick Start file in the Tutorials folder.

2.0 Starting a Model

Open RS3. You will see a blank workspace.

Select: Analysis > Project Settings

Our first step is to configure the analysis parameters for the model. Always check that you are working with the right units.

Units

Select the [Units] tab.

By default, the project settings dialog will be displaying the [Units] tab.

Set Units to Metric, stress as kPa and keep everything else as default. The dialog should look as shown below:

Project Settings Dialog under Units tab

Now we will be adding additional Stages to our analysis.

Stages

Select the [Stages] tab. Enter Number of Stages = 5 and input each stage name as shown in the table below:

Stages	Stage Name
1	Initial
2	Excavate Tunnel
3	Excavate Foundation
4	Pour Concrete Foundation
5	Loading Foundation

We will be applying different procedures at each stage, so it is important to keep track of the stages by labeling them with relevant names.

After inputting the stage names, the dialog should look as follows:

Project Settings Dialog under Stages tab

For this model, we will NOT be including any groundwater in the analysis so we must indicate this in the project settings.

Groundwater

Select the [Groundwater] tab. By default the Method is set to Phreatic Surfaces. Change Method to None.

More details on this feature are provided in Online Help (Keyword search: Project Settings/Groundwater). We will be covering this topic in more detail with the Transient Dam tutorial.

The dialog should look as follows:

Project Settings Dialog under Groundwater tab

Click OK to save and close the project settings dialog.

3.0 Defining the Materials

RS3 is designed with an intuitive workflow to help guide the user through the required steps in creating a model. Under each tab, the toolbars and menus are customized to provide the user with the functions they will need in each step of creating their model.

We will begin with the Geology workflow tab
Select: Materials > Define Materials

The Define Materials dialog has several tabs that are used to assign different material properties.

By default, RS3 assigns “Material 1” to all entities created in the Geology tab. You can save some time assigning materials by defining "Material 1" as the material you want the majority of your model to have.

Enter the following properties for “Material 1” and “Material 2” in the [Initial Conditions] and [Stiffness] tab. Leave the other options with default settings.

	Name	Initial Loading	Unit Weight (kN/m3)	Young's Modulus (kPa)	Poisson's Ratio
Material 1	Soil	Field Stress & Body Force	20	20000	0.3
Material 2	Concrete	Body Force Only	27	280000	0.3

The Material Properties dialog for Soil should look like the following:

Material Properties dialog box

Select OK to save and close the Material Properties dialog.

4.0 Creating Geometry

Ensure the Geology workflow tab is still selected from the workflow.

RS3 uses an external box to act as the boundaries of the model; only objects contained within or a part of the external box will be considered in the calculations. As such, when creating a model, it is important to realize the model’s bounds before setting up the external box

Select: Geometry > Create External Box
A Create External dialog will open. Enter:
1. First Corner (x, y, z) = (0, 0, 0)
2. Second Corner (x, y, z) = (30, 30, -20)
Click OK.
The external volume geometry should now be displayed in the viewports. Under the visibility pane on the left, select the 'External' volume and re-name it to 'Soil' using properties pane below. Your screen should look like the following:

Screenshot of External Volume

When creating geometry keep in mind that RS3 uses the Z direction as the default for the direction of gravity. Orient your model accordingly.

5.0 Excavation

Select the Excavations workflow tab

5.1 CREATING A CYLINDER FOR THE UNDERGROUND TUNNEL

We will now define a cylinder to represent the underground tunnel.

Select: Geometry > 3D Primitive Geometry > Cylinder
Enter the following axis and properties:
1. Axis Start Point (x, y, z) = (10, 0, -10),
2. Axis End Point (x, y, z) = (10, 30, -10),
3. Radius = 1
4. Subdivisions = 25
5. Role = Excavation
Click OK to save and close the dialog.

Create Cylinder dialog

The model should now look like the following:

image of model

Next, we are going to represent the foundation by creating an extruded circular polyline.

We could easily create the foundation through defining another cylinder as we did above for the tunnel, but for the purpose of demonstrating the draw polyline feature of RS3, this cylinder will be created through a different (more lengthy) process.

5.2 EXTRUDING A CIRCLE FOR THE FOUNDATION

Select: Geometry > Polyline Tools > Draw Polyline . A Draw Polyline pane will open on the left side of the screen.
Set Plane Orientation = XY
Now input the following:
1. XY Origin (x, y, z) = (17.5, 15, 0)
2. Path Definition = Circle
3. Circle Definition = Center and Radius
4. Radius = 5
5. Coordinate Input U, V = 0, 0. Press Enter.
Click the green checkmark located at the top-right corner to close the pane.

You can click the grey arrow beside Discretization Settings to enable the Number of Segments and Segment Length options. With these two options you can input the number of straight-line segments (that define the circle) and the approximate segment length, respectively. For the purposes of this tutorial the default is fine.

The model should look as shown below:

Model view (from 4 viewports) with circle polyline

If you want to rotate the 3D perspective model, select the counterclockwise arrow in the 3D viewport or select the viewcube and rotate the box to your liking.

Select Polyline in the visibility pane.
Select: Geometry > Extrude/Sweep/Loft Tools > Extrude

You can also extrude the polyline by selecting the Extrude icon in the toolbar

An Extrude Geometry dialog will appear as shown below.

Under Direction keep (x, y, z) = (0, 0, 1) and change Depth = -0.5.
Click OK.

Extrude dialog

Notice only the external layer is locked from the visibility tree. This is because the layer is defined as an external volume and the geometry CANNOT be modified.

The other entities (Cylinder and Polyline_extruded) in the visibility pane are geometry objects that are currently not interacting with the external volume.

Visibility Pane dialog

In order to integrate these objects into the external volume of the model, we need to use the Divide All Geometry function to convert the geometry objects to sub-volumes in the main model.

5.2.1 Divide All Geometry

Now that we’ve defined the external box and the objects to be cut into it, we can use the Divide All Geometry function.

Make sure none of the geometries in the visibility pane are selected so the function can be applied throughout the whole model. If you want to divide specific geometries separately, select the geometry of interest and apply the Divide All Geometry function.

Select: Geometry > 3D Boolean > Divide All Geometry

The Divide All Parameters dialog helps users to fine-tune the behaviour of the Divide All function. Setting Quality to the Default option is suitable for a wide range of models in general, however, there are cases where changing the setting is required to successfully intersect every geometry with the external volume.

For more detail about each option under Divide All Parameters, please refer to Divide / Un-Divide All Geometry.

We will keep everything default for now.
Click OK to begin dividing.

Your model should now look similar to the one below.

Model after using the Divide All function

If you look at the visibility pane you will notice that the names of each geometry are labelled with numbers. You can remove the numbers by simply selecting each and changing the names in the properties pane.

Select each geometry volume in the Visibility pane and name them according to the table below:

Geometry Entity	Name
Cylinder_1	Underground Tunnel
Soil_2	Soil
Polyline_extruded_3	Foundation

6.0 Staging

6.1 STAGING THE TUNNEL EXCAVATION

The Underground Tunnel is excavated at Stage 2. Therefore in Stage 1 it should still be modeled as “Soil”. While still in the Initial stage, make sure for Underground Tunnel that the Applied Property in the properties pane is set to Soil.

RS3 separates stages through tabs at the bottom of the window. As you select each stage the viewports will update the loads, materials, and other elements that were assigned that specific stage. This feature makes it easy to view the different states of the model at each stage.

Now we will move to the Excavate Tunnel stage.
Select the underground tunnel in the Visibility pane and in the Properties pane change the Applied Property = No Material.

Once you change the property of a body, RS3 will automatically carry over that property to all subsequent stages (e.g. if a body was excavated in Stage 1, indicated with Applied Property = No Material, the body will have an applied property of No Material for all subsequent stages).

6.2 STAGING THE FOUNDATION

Now we do the same thing for the foundation as we completed for the tunnel, but starting from the Excavate Foundation stage.

Select the stage tab Excavate foundation.
Select the foundation volume from the Visibility pane and in the Properties pane, change Applied Property = No Material.
Now select the Pour Concrete Foundation stage, and in the Properties pane change the Applied Property = Concrete.

RS3 also provides a quick visual summary of the currently selected object’s state in each stage. For example, if you select the foundation in the visibility pane, on top of the stage tabs, you’ll notice stage 1 and 2 have a purple line above (indicating it is material 1), stage 3 is white (indicating it is defined as no material), and stage 4 and 5 are both light green (concrete).

Stages Summary tab

7.0 Adding Stress Loading

7.1 APPLYING A SURFACE LOAD TO THE MODEL

Select the Loads workflow tab

This tab allows you to edit the loading conditions. We will be applying a uniformly distributed load onto the foundation surface.

Select: Edit > Selection Mode > Faces Selection
Select the top face of the foundation either using the XY-plane modeler view or the 3D modeler view. When selected the 3D modeler view should look similar to the following:
Select: Loading > Add Loads to Selected.
Enter the following:
1. Magnitude = 200 (kN/m2)
2. Install at Stage = Loading foundation
For all other options keep the default values.

Notice that by default the Load Type is set to Uniform Load. This will allow the users to apply uniformly distributed load on the area of interest.

Click OK to save and close the dialog. Before closing you can check to see if your dialog looks like the one below:

Apply Load to Selected Faces dialog

7.2 APPLYING A FIELD STRESS

The Field Stress option allows you to edit the field stress loading conditions.

Select Loading > Field Stress.
Leave the settings as their default values (e.g. Field Stress Type is set to Gravity).
Click OK.

Field Stress is applied to elements where initial element loads are defined with field stress. If the elements do not have field stress assigned (i.e. initial element loading set to Body Force Only) this stress will NOT be used at all. Since we have soil with initial element load set to Field stress & Body Force, this load will be applied in our model. Please refer to RS2 online help for more information about initial element loading.

8.0 Setting Boundary Conditions

Move to the Restraints workflow tab to assign restraints to the external boundary of the model.

RS3 has a built-in "Auto Restrain" tool for use on underground models. For the purpose of this tutorial we will use the Auto Restrain (Surface) option.

Select: Restraints > Auto Restrain (Surface) . The model should look as the following:

3D modeler view after Auto Restaint

This completes the construction of our model's geometry.

9.0 Meshing

Next, we move to the Mesh workflow tab

Here we may specify the mesh type and discretization density for our model. For this tutorial, we will use the default settings.

Select: Mesh > Mesh Settings

Mesh Settings dialog

Make sure that Element Type = 4-Noded Tetrahedra and Mesh Gradation = Graded.

For Element Type there are two types available; 4-noded tetrahedra and 10-noded tetrahedra. The 10-noded tetrahedra has mid-side nodes and has more computational points. Using the 10-noded tetrahedra generally yields more accurate result at the cost of computation time. For more accurate results, it is recommended that you use the 10-noded tetrahedra type and 4-noded tetrahedra if computational efficiency is a priority.

Click Mesh to mesh the model. Click OK to close the dialog.

In case if you selected OK before Mesh, your model will not have a mesh. You can simply select Mesh > Mesh to mesh the model.

10.0 Computing Results

Next, we move to the Compute workflow tab
From this tab, we can compute the results of our model. First, save your model:File > Save As.
Next, you need to save the compute file: File > Save Compute File.
You are now ready to compute the results. Select Compute > Compute

The RS3 Compute engine will perform the required finite element calculations. This computation may take a few minutes; however, more complex models may take longer to compute. Once the computation is complete, the dialog will close.

Compute dialog

11.0 Interpreting Results

11.1 DISPLAYING THE RESULTS

Next, we move to Results workflow tab

From this tab, we can analyze the results of our model. First, let's refresh the results.

Select: Interpret > Refresh All Results

Refreshing the result allows us to plot new results of the model. Although we did not have any previous results from this model, it is good practice to refresh results before we view new contour plots.

On the top right corner of the screen you should see two drop-down menus; Element = Solids and Data Type = Sigma 1 Effective by default.

Results tab drop down menu

The “Element” drop-down menu allows you to view the results for solids, bolts, and liners. For this tutorial, we can only view results for Solids.

We will analyze a number of different “Data Type” results. Let’s turn on the exterior contours so we can see some results.

Select: Interpret > Show Excavation Contour
Select: Interpret > Show Data on Plane > XZ Plane
Enter the following origin (x, y, z) = (18, 15, -10).
Select Add and then Close. You should now see a contour plot in the XZ plane.

XZ Plane Contour in 3D modeler view — XZ Plane Contour in Stage 2 (Excavate Tunnel)

11.2 DISPLAYING THE PRINCIPAL STRESS RESULTS

In order to compare each stage against each other visually, the contour colour scheme should be standardized across all stages. We can do this by:

Select: Interpret > Contour Legend > Contour Options
Select Auto Range (All Stages) as shown below.
Click OK

The Sigma 1 Effective results for stages 4 and 5 are shown below in different views:

	Sigma 1 effective at Pour concrete foundation (Stage 4)	Sigma 1 effective at Loading foundation (Stage 5)
2D view
3D view
Legend

As shown in the contour plot, we can see the changes in the stress distribution across the soil model as a load of foundation is applied at stage 5. Next, we will investigate the change in the displacement across stages 2 to 5.