GEOSTUDIO 2018, SLOPE/W MANUAL
ON
EMBANKMENT DAM
BY
ENGINEER AMDEMARIAM SHIFERIE MULU
FROM
ADDIS ABEBA UNIVERSITY, INSTUTUTE OF WATER RESOURCE
FOR
MINISTRY OF IRRIGATION AND LOWLAND
AUGUST, 2023
ADDIS ABEBA, ETHIOPIA
i
Contents
1. Introduction .................................................................................................................... 3
2. Defining a project and Geometry .................................................................................... 3
3. Creating and Assigning Material .................................................................................... 3
3.1. Creating materials ................................................................................................... 3
3.2. Assigning material each region ............................................................................... 5
4. Verifying the input data .................................................................................................. 8
5. Solve and Contour ......................................................................................................... 9
5.1. Steady State Loading Condition (D/S)..................................................................... 9
5.2. Steady State Loading Condition (U/S)................................................................... 13
5.3. At the end of construction (D/S) ............................................................................ 14
5.4. Sudden drawdown (U/S) ....................................................................................... 18
6. Reporting ..................................................................................................................... 24
7. Adding Additional Analyses .......................................................................................... 25
2
1. Introduction
This exercise will help us to obtain the minimum factor of safety and the critical surface
profile
2. Defining a project and Geometry
We can use the geometry from SEEP/W Exercise
3. Creating and Assigning Material
3.1. Creating materials
Materials are first created and then assigned to geometry objects.
Click on Define analysis and click Materials: to create a material.
For the first region add a new material, name it and select a strength model from the
drop down list. You can use the tab key to move between the edit boxes. You may put
the name as clay core, Material model as Mohr-Coulomb and Basic material properties
as
Material Unit weight Cohesion Phi (o)
(KN/m3) (kPa)
Rock fill 26 0 40
Clay core 28.8 80 18
Fine Filter 21 0 38
Coarse Filter 24 0 38
soil foundation 23.3 5 35
Rock foundation 23.3 5 35
To create the other material, we have choices; we can either add one, or we can clone
the existing material.
3.2. Assigning material each region
The materials can now be assigned to the individual geometry regions. Choose
materials from the DRAW: dropdown menu
Then click the material to get the following dialog box.
Then drag the respective colour and paste on respective region. The colour for the
region can be done by dropdown menu from assign.
Now Choose Slip Surfaces from the DRAW menu. Use the curser to define “zones”
where the slip surface will enter and then exit the ground surface line.
Insert the following ranges for Entry range (left side) and Exit Range (Right side). This
is for downstream slope analysis. But for upstream side the entry will right side and
exit will be the left side.
Now the problem definition has been completed.
4. Verifying the input data
Choose solve manager from the window drop down list and SLOPE/W will run a
number of checks to see if there are any errors or warnings. if there is any problem we
can check back the procedures and the input data.
5. Solve and Contour
Click the stat button to run the simulation. When the simulation is done correctly the
status will be changed into Solved
5.1. Steady State Loading Condition (D/S)
The critical slip surface appears along with the critical factor of safety.
Use the Draw: Slip Surfaces command to bring up a dialogue box that summarizes
the factors of safety for all the different slip surfaces that were analyzed. When you
click on any single slip surface, you will cause both the slip surface and the
corresponding factor of safety to appear in the CONTOUR window.
You can also review the slice force information for the most critical slip surface. Move
the cursor inside any particular slice and click the left mouse button to select the slice.
The force information can be copied and pasted directly into a report or spreadsheet.
Although we told the program to use the Morgenstern-Price method of analysis, results
were also obtained for three other methods including Ordinary, Bishop, spencer
,Janbu and others.
It is often helpful to look at how parameters vary across the slip surface. To create a
graph, choose Graph from the Draw Menu. There are many different types of graphs
that can be developed, including a plot of pore-water pressures across the slip surface.
Both the graph and the raw data can be copied from SLOPE/W and pasted into a
report or a spreadsheet for further analysis.
By default, the location of the critical slip surface is shown in CONTOUR; however you
can also view the location of the other slip surfaces that were analyzed. Choose
Preferences from the View menu. Select the number of slip surfaces that you would
like to view simultaneously.
5.2. Steady State Loading Condition (U/S)
Change the direction of movement from Right to Left for upstream slope
Then you can click the solve icons to do the simulation and see the results
respectively.
5.3. At the end of construction (D/S)
We can check the dam slope stability at the end of construction for upstream and
downstream slope using the following data.
Pore-pressure ratio data
Pore-water pressure
Pore-water pressure ratio Ru
Sn. Material zone ratio Ru during
at end of construction
construction
1 Clay fill 0.5 0.4
2 Fine filter -- --
3 Coarse filter
4 Rock fill -- --
5 Soil foundation 0.35 0.3
6 Rock foundation 0.35 0.3
Let us define the problem for downstream slope at the end of construction.
Input the pore water pressure (Ru) data
Now we can apply the material
Give Entry and exit for downstream slope at the end of construction
Run the problem by clicking the solve manager from window menu
5.4. Sudden drawdown (U/S)
Before check the upstream slope during sudden drawdown it is convenient to create
the transient seepage analysis which used as parent analysis.
Let us consider the evacuation time is 15 day during drawdown. Fill the duration in
second with 15 steps and step increase linearly.
Now we can create new boundary for 15 day evacuation duration for specific water
depth as follow.
The boundary condition will be in function and the kind should be water total head.
Fill the following time vs water total head with spline data function type
Time (sec) Water Total Head (m)
0 26
864,000 13
1,036,800 6
1,296,000 0
Apply the new boundary condition
It is time to hit the solve manger to run the simulation
The transient seepage analysis has completed.
Now we can define the problem for sudden draw down upstream slope by taking the
transient seepage analysis as parent.
Tick direction of the movement from right to left under slip surface dropdown
Apply the Entry and Exit from draw menu
Now we can solve the problem
6. Reporting
New to GeoStudio 2018 is the reporting feature. If you need to generate a report for
both your input and output; select Report from the View menu. Once you save the
report file, your default word processing program will open with a generated report.
You can now insert pictures, apply style templates or add and delete data.
If at any time you need help with understanding a dialogue box, you can click on the
question mark in the top left corner to access the on-line help or use F1 on your
keyboard.
7. Adding Additional Analyses
Another powerful feature in GeoStudio 2018 is the ability to conduct multiple analyses
in a single project file. If you want to see what the results would be for different input
parameters on the same geometry, you can add or clone analyses using the Define
Analysis
