Select Save. The data will be saved to the file SIGMA

Tutorial.GSZ. Once it is saved, the file name is displayed in the DEFINE window title bar.

The file name may include a drive name and directory path. If you do not include a path, the file will be saved in the directory name displayed in the Save In box.

All GeoStudio files have a GSZ file name extension. SIGMA/W will add the extension to the file name if it is not specified. If you have several different GeoStudio modules, it is likely wise to be descriptive in your file name, i.e., if you had simply called this SIGMA/W tutorial example TUTORIAL.GSZ and then completed a SLOPE/W tutorial example which you also called TUTORIAL.GSZ, one file would replace the other if they were saved to the same directory.

The next time you choose File Save, the file will be saved without first bringing up the Save File As dialog box. This is because a file name is already specified.

Sketch axis

Sketching an axis facilitates sketching the problem as well as viewing and

interpreting the results. The Snap to Grid option should still be activated. Drawing an axis with the Snap to Grid feature enabled will allow you to define an evenly-spaced region for the axis.

¾ To sketch an axis:

1. Choose Axes from the Sketch menu. The following dialog box appears:

2. Ensure the Left Axis, Bottom Axis and Axis Numbers check boxes in the Display group box are selected. The Top Axis and Right Axis check boxes should be unchecked.

3. Type an appropriate title for the bottom X-axis in the Bottom X edit box.

4. Type an appropriate title for the left Y-axis in the left Y edit box.

5. Select OK. The cursor will change from an arrow to a cross-hair, and “Sketch axis” will be added to the status bar, indicating the mode in which you are operating.

6. Move the cursor near position (0,0). Hold the left mouse button down, but do not release it. As you move the mouse, a rectangle appears.

7. Using the coordinates that appear in the status bar on the bottom right corner of the GeoStudio window as a guide, “Drag” the mouse near (38, 25) and release the left mouse button.

An axis is generated that represents 38 m in the x direction and 25 m in the y direction. The View Preferences command allows you to change the font and the size of the axis numbers. For more information about this command, see View Preferences in the on-line help.

The number of increments along each axis is calculated by SEEP/W when the axis is generated. Choose the Set Axes command and select OK to bring up the axis edit menu if you wish to override these values.

Sketch the problem

In developing a finite element mesh, it is convenient to first prepare a sketch of the problem. This sketch is a useful guide for drawing the finite element mesh and defining the boundary conditions.

¾ To sketch the foundation of the problem:

1. In the toolbar, click on the Zoom Page button with the left mouse button.

The entire working area is displayed in the DEFINE window.

2. Choose Lines from the Sketch menu. A dialogue box will appear which can be used to alter the appearance of a sketch line, creating a thick or thin line with arrow heads. Notice the cursor has changed from an arrow to a cross-hair, and the status bar indicates that

"Sketch Lines" is the current operating mode.

3. Leave the dialogue box untouched or move it out of the way if necessary. Using the mouse, move the cursor near position (0,0), as indicated in the Position window, and click the left mouse button.

The cursor snaps to the grid point at (0,0). As you move the mouse, a line is drawn from (0,0) to the new cursor position.

4. Move the cursor up near (0,25) and click the left mouse button. The cursor snaps to (0,25) and a line is drawn from (0,0) to (0,25).

5. Move the cursor to the right near (38,25) and click the left mouse

button. A line is drawn from (0,25) to (38,25).

6. Move the cursor down near (38,0) and click the left mouse button. A line is drawn from (38,25) to (38,0).

7. Move the cursor back to (0,0) and click the left mouse button. A line is drawn from (38,0) to (0,0).

8. Click the right mouse button or press ESC to finish sketching a line.

The cursor will change from a cross-hair back to an arrow; you are then back in Work Mode.

After you have completed the above steps, your screen should look like the following:

If you sketch a line in the wrong position, use the Modify Objects command to move it. For more information about this command, see the on-line help.

You should now know how to sketch a line. Sketch the tank in the same way you sketched the foundation:

1. Choose Sketch Lines.

2. Position the cursor and click the left mouse button at (0,25), (0,29), (5,29), and (5,25).

3. Click the right mouse button or press ESC to finish sketching the tank.

4. In the tool bar, click on the Zoom Objects tool with the left mouse button.

The drawing is enlarged so that the lines you just sketched fill the DEFINE window. If you are using a mouse with a scroll wheel, you can zoom in and out of the drawing by moving the scroll wheel.

Sketch the stratigraphic boundary line in the same way:

1. Choose Sketch Lines.

2. Position the cursor and click the left mouse button at (0,20) and then at (38,20).

3. Click the right mouse button or press ESC to finish sketching the boundary line.

¾ To label the tank:

1. Choose Sketch Text. The following dialog box is displayed:

2. Type Tank in the Text edit box.

3. To specify the size of the text, select the Font button. The following dialog box appears:

4. Select 24 in the Size list box and select OK in the Font dialog box.

5. Select OK in the Sketch Text dialog box.

The cursor changes from an arrow to a cross-hair and the status bar indicates that

"Sketch Text" is the current operating mode.

6. Click the left mouse button at approximately (1,26).

Tank is displayed on the drawing at the cursor position.

7. Click the right mouse button or press ESC to finish defining the label.

After you have completed the above steps, your screen should look like the following:

Identify the problem

¾ To name and identify the problem:

1. Choose Analysis Settings from the KeyIn pull down menu. The following dialog box appears.

2. Type in any appropriate text in the Title edit box and the Comments edit box.

This information will be written to all data input and output files. Leave the dialogue box open.

Specify the analysis type

Since the tank is a right circular cylinder, its geometry is axisymmetric about its vertical axis. You can analyze this problem as an axisymmetric load/deformation analysis.

¾ To specify this information:

1. Select the Control Tab from the Analysis Settings dialogue.

2. Click in the button beside Axisymmetric in the View group box.

3. Select the Type tab. The Load/Deformation button should be

selected in the Type group box and the Adjust Fill to Design Elevation option should be unchecked.

4. Select OK.

Define the soil properties

A linear-elastic, total stress analysis will be performed to solve this example problem. Only the stiffness modulus E and Poisson's Ratio ν are required for this type of analysis. The values of these parameters are given in Figure 4-1.

¾ To define the soil properties:

1. Choose Material Properties from the KeyIn pull down menu. The following dialog box appears, containing one default material:

2. To define the upper soil layer, click on Material #1 in the list box.

The values for Material #1 are copied into the edit boxes below the list box.

3. Click the down arrow beside the Model edit box. A drop-down list appears, containing the different soil models available. Select Linear-Elastic from the list.

The E Modulus and Poisson’s Ratio edit boxes appear in the dialog box.

4. Type 4000 in the E Modulus edit box.

5. Type 0.45 in the Poisson’s Ratio edit box.

In the Parameter Type drop-down list box, leave it set to the default selection (Total).

6. Select Copy .

The new parameter values for Material #1 are copied from the edit boxes into the list box. A default colour (yellow) has been assigned to Material #1.

7. Type 2 in the # edit box to indicate that you are now defining Material 2 (the bottom soil layer).