Anchored Sheet Pile Wall

1.0 Introduction

This tutorial introduces how to model and analyze an anchored sheet pile support system in staged excavation. It uses some of the support features of RS3 such as Liner, joints and bolts for modelling sheet pile and anchors respectively. In the model, the sheet pile walls are installed first. Then, the ground is excavated in different stages. After each stage of excavation, bolts are installed. The model contains two separate layers and the geometry of the model is provided in the initial file.

This example is the extruded version of RS2 - Anchored Sheet Pile Wall. The geometry is imported and extruded in 1 meter in an out-of-plane (z) direction.

All tutorial files installed with RS3 can be accessed by selecting File > Recent > Tutorials folder from the RS3 main menu. The initial file of the tutorial can be found in Anchored Sheet Pile Wall-starting file.rs3v3 and the finished tutorial can be found in the Anchored Sheet Pile Wall.rs3v3 file.

2.0 Starting the Model

After opening the initial file, go to Project Settings:

1. Select: Analysis > Project Settings.

The Project Settings dialog is used to configure the main analysis parameters for your RS3 model.

1. Under the tab [Units], set Units as Metric, stress as kPa. The dialogue should look as shown below:
   
2. Select the [Stages] tab. Enter Number of Stages = 5, with names as shown below. We will be applying different procedures at each stage, so it is important to keep track of the stages by labelling them with relevant names.

Stages	Stage Name
1	Initial
2	Install Sheet Pile Wall
3	Excavate/Install first bolts
4	Excavate/Install second bolts
5	Add Load

After inputting the stages, the dialog should look as follows:



3. Click OK to close the dialog.

3.0 Assigning the Materials

Before we assign the material, we have to create external volumes.

1. Select: Geometry > 3D Boolean > Divide All
   
2. Use Default for Quality and click OK.
3. You will see the volumes created. Make sure the select entityis selected in toolbar, then select the top three volumes by ctrl + left click on volumes as shown here.
   
4. The material properties are already provided in the model. Go to properties pane under visibility tree and select Material1_dup. If you want, you can also select Materials > Assign Properties.
   
5. Select Apply then you will see the materials are applied on the top volumes.
6. Similarly, we will follow the same procedure for the next bottom layers. Ctrl + left click on bottom volumes.
   
7. We will apply material to Clay. Select: Material > Assign Materials as shown below:
   
8. Select Apply. Then you will see that materials are applied to two layers as shown below:
   
9. We will now assign staged excavation. Select the first left top volume of the geometry as shown below.
   
10. Select the third stage 'Excavate / Install first bolts' and change the Role to Excavation with Applied property to No Material in the properties pane.
11. Similarly, now select the volume below and select the Excavation for Role and change the Applied property to No Material in the properties pane.

When you click on different stages, you will notice the excavation volume in stages 3 and 4. Now we will move onto supports.

4.0 Defining the Lining Composition

1. Select: Support > Liners > Defining the Lining Composition

In lining composition, RS3 allows you to model a liner composition with joints surrounding the liner.

1. To add joints between the liner, press the up/down arrow button on the liner. As you see in this dialog, the joints are already assigned on both sides of the liner.
2. To see the properties of the joints, select the edit iconbeside Joint 1_dup and you will see the following property dialog pop up.

For more information regarding the parameters used in this dialog, please refer to Define Liner Interface Properties. Similarly, if you click on the edit iconfor liner, then you will see the liner dialog as shown.

Notice that thickness is 0.2m and the geometry of our liner reflects this thickness.

5.0 Assigning the Lining Composition / Bolts

Before we assign the support, we will hide some volumes of the geometry to make it easier for us to assign the liner.

1. Select the following volumes and hide the volumes by selecting theicon.

5.1 Assigning Liner

1. You will then see the small column of volume is left in the modeler. Set the selection mode to 'Face selection'and ctrl + left click on the three surfaces facing the excavation volume as shown.
   
2. Then, select Support > Liners > Add Lining.
3. Under Staging, set Install at stage to the 'Install Sheet Pile Wall' stage.
   
4. Click OK and you will see the liner is applied on the surface as shown below:

5.2 Defining/Assigning Bolts

Before applying the bolts to our model, we will first check the bolts properties.

1. Select: Support > Bolts > Define Bolts.
2. You will see the list with Bolt 1_dup. Select the Bolt 1_dup and you will see the following material property shown:
   
3. Click OK. Now we will use this bolt to assign it to our liner layer.
4. Select the first top surface of the liner as shown below.
   
5. Select Support > Bolts > Add Bolts to Surface. Make sure the Bolt 1_dup is selected under bolt properties. We will assign bolt with the following material property:
   • Trend & Plunge : -90 deg Trend / Plunge 20.5 deg.
   • Length: 8.5 m
   • Install at stage: Excavate / Install first bolts

Primary path inputs are:

• Primary path (required): Start: (14.34 12.17 4.83) and End (14.34 13.37 4.83)
• Primary spacing (m): 0.99 m * (we set it at 0.99 meters because the extruded model is 1m and the bolt will only show one side of support if 1 meter is entered)
• Primary offset (m): 0 m
• Secondary Spacing (m): 0 m
• Secondary offset (m) : 0m



6. Make sure to click Preview Pattern. Then click Add.

We will now assign the next layer of bolts. Make sure the selection mode is back to Face selection.

1. Select: Support > Bolts > Add Bolts to Surface. Select Bolt 2 under bolt property. We will assign bolt with the following material property:
   • Trend & Plunge : -90 deg Trend / Plunge 20.5 deg.
   • Length: 8.5 m
   • Install at stage: Excavate / Install first bolts

Primary path inputs are:

• Primary path (required): Start: (14.34 12.17 0.83) and End (14.34 13.37 0.83)
• Primary spacing (m) : 0.99 m
• Primary offset (m): 0 m
• Secondary Spacing (m): 0 m
• Secondary offset (m) : 0m



2. Press Preview Pattern, then press Done.

Then you will see the model as shown below:

1. Turn on all the geometry to view the full model by turning on theicons on layers of the geometry in visibility tree.

6.0 Adding Loads

We will now add the load on top of the surface as shown below.

1. Select: Loads > Add Loads.
2. As show below, enter:
   
   • Width = 10 m
     
   • Height = 1 m
   • Magnitude = 10 kPa



3. For Staging, click Define. Install at stage Add Load as shown below (last stage). Click OK.

Then you will see the load applied as shown below:

7.0 Restraints

We will now add restraints to the model.

1. First, make sure only the sides of the thin surfaces are selected in the XZ plane.
2. Select: Restraints > Add Restraint / Displacement > Restrain Y.
   
3. Then, select the other surfaces in the YZ direction and then add restraint in XY directions.
4. Select: Restraints > Add Restraint / Displacement > Restrain XY.
   
5. Lastly, select the bottom layer (XY plane) and select Restrain XYZ.
6. Select: Restraints > Add Restraint / Displacement > Restrain XYZ.
   

8.0 Meshing

1. Next, we move to the Mesh workflow tab.

Here we may specify the mesh type and discretization density for our model.

1. Select: Mesh > Mesh Settings
2. For this tutorial, we will use a default setting,4-noded tetrahedra graded mesh.
   
3. Click Mesh to generate the mesh, and then OK.
   

The mesh is now generated, your model should look like the one below.

Now we move on to computing the results.

9.0 Computing Results

9.1 COMPUTING THE MODEL

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

10.0 Interpreting Results

10.1 DISPLAYING THE RESULTS

1. Next, we move to Results workflow tab
2. Go to Stage 5 and you will see the following Sigma1 Effective stress result as shown:

As you can see from RS2 results, the sigma1 effective stress is around 350 kPa as shown below, which is close to what we have obtained in RS3.

1. Select Total displacement for contour plot.

As you can see from RS3 and RS2, both give a maximum displacement of 0.091 m.

This concludes the Anchored Sheet Pile wall tutorial.