# Stability of Dam

## 1. Introduction

This model demonstrates how to create a 3D model of a dam across a valley.

Select File > Recent > Tutorials and open the file Stability of Dam – starting file

This file contains the cross-sectional profile geometry of a valley, dam and water table, as shown below.

The coordinates were entered using the Draw Polyline option, and pasting x,y,z coordinate values into a table, as described in Tutorial 01 - Simple Extruded Slope with Water Table.

## 2. Project Settings

In Project Settings > Symmetry turn on the Symmetric Model checkbox. Enter the points (x, y) = (180, 0) for Point 1and (x, y) = (180, 225) for Point 2 to set the line of symmetry running through center of the model. Select OK.

## 3. Extrude

### 3.1 EXTRUDE VALLEY

Select the Valley entity in the sidebar visibility tree.

Select: Geometry > Extrude/Sweep/Loft Tools > Extrude

In the Extrude dialog, enter Depth = 225 and select the Close Volumes checkbox. Select Preview to preview the result before finalizing. Select OK to extrude the valley 225 m in the y-axis.

### 3.2 EXTRUDE DAM

In the sidebar visibility tree, select the Outer Dam Core and the Inner Dam Core entities.

Select: Geometry > Extrude/Sweep/Loft Tools > Extrude

In the Extrude dialog, enter Depth = 360 and select the Close Volumes checkbox. Select Preview. Select OK to extrude the dam geometry 360 m in the x-axis.

### 3.3 EXTRUDE WATER TABLE

In the sidebar visibility tree, select the GWT (ground water table) entity

Select: Geometry > Extrude/Sweep/Loft Tools > Extrude

In the Extrude dialog, enter Offset = 0, Depth = 400. Select Preview. Select OK to extrude the water table 400 m in the x-axis.

## Set Valley Volume as External

In the sidebar visibility tree, select the Valley_extruded entity

Select: Geometry > Set as External

## Add Inner Dam/Outer Dam volume to External

Select the Inner Dam Core in the sidebar tree.

Select: Geometry > Add to External

Select the Outer Dam Core in the sidebar tree.

Select: Geometry > Add to External

This automatically intersects the dam geometry with the valley geometry and creates a union forming the External boundary.

The order of adding entities to external matters. If you add Outer Dam core first and then add Inner Dam core you will get a dividing error and the add to external process won’t be accomplished properly

## 5. Set Water Table as Surface

Select the GWT in the sidebar tree.

Select the Groundwater tab.

Select: Groundwater > Add Water Surface

Select OK in the Add Water Surface dialog.

The GWT (ground water table) has now been assigned as a water surface.

Select OK in the Hydraulic Assignments dialog to assign the Water Table as the water surface for all materials.

## 6. Material Properties

Select: Materials > Define Materials from the toolbar. The three materials have already been predefined (valley, inner core, outer core).

Select the Water Parameters tab in Define Materials to verify that the water table has been assigned to each material.

### 6.1 ASSIGN MATERIALS

In the Visibility tree, select the valley, inner core and outer core entities and assign the corresponding materials to each by selecting them from Applied properties in the Properties pane.

Or Select: Materials > Assign Materials. Select the entity in the model by clicking on it and assign it to its corresponding material.

The outer core has two sections, upstream and downstream; each must be assigned the outer core material.

Same for outer dam and inner dam, select the item and apply the property accordingly.

## 7. Surfaces

We will use the default Spline surface search with optimization.

## 8. Compute

Save the file. Select Compute to run the analysis. The Spencer results are shown below:

This concludes the Stability of Dam tutorial.