Welcome to Getting Started with GeoStudio video series.
This tutorial introduces how to use the QUAKE/W product of GeoStudio 2012.
This tutorial video has been designed to help walk new users through the basics of setting up a dynamic earthquake analysis in QUAKE/W.
So, if you are new to QUAKE/W and are not sure where to start, you have come to the right place.
The main topics that will be covered in the tutorial
will be how to create an analysis in QUAKE/W
by using the define view to set up the analysis,
the solve manager to solve the numerical analysis,
and the options available in results view to gain a deeper understanding of the analysis.
If you are not familiar with GeoStudio Products,
it is recommended that you start with the tutorial videos for SEEP/W,
SIGMA/W, or SLOPE/W
to gain an understanding of the tools available for drawing your geometry domain,
creating sketches, or explanations on basic options that are available in all GeoStudio Products.
This tutorial video will mainly discuss
QUAKE/W options and tools where they differ from SEEP/W,
SIGMA/W or SLOPE/W.
So, let's get started.
This example will include two analyses. The first will be an initial static stress analysis
to determine the stress state conditions that exist prior to the earthquake.
The second analysis will simulate the dynamic response of the embankment during an earthquake event.
The objective of this tutorial is to analyze the dynamic response of a loose soil deposit in terms of the motion that will occur at the crest of the
embankment during an earthquake event and to estimate the excess pore-water pressures that may develop in a loose foundation soil.
We will start with both analyses already created with our ground region and embankment already drawn.
If you are unsure of how to use the visualization sketching tools or draw the geometry regions,
please refer to the sketching tools and geometry video tutorial
or the introduction tutorial videos to SEEP/W, SIGMA/W,
or SLOPE/W.
Now we will add the materials for the two soil regions to our analysis.
I will go to KeyIn,
materials to open the materials define window.
I will add a new material and give my material a name.
I will then choose the linear elastic option from the drop down menu.
For the embankment soil, we will use a unit weight of 16 kilonewtons per cubic meter,
damping ratio of 0.1,
and a constant GMax or shear modulus of 5000 kilopascals.
For the foundation material, we can either add a new material
or clone the current material if similar properties are required.
Since we are using the same material model for the foundation, we will clone the embankment material
and change the unit weight to 18 kilonewtons per cubic meter.
Since we would like to model the excess pore-water pressures within the foundation
in the dynamic analysis,
at least two functions are required.
The first is the pore-water pressure ratio function
and the second is the cyclic number function.
In this example, we will use the sample functions for both.
In the pore-water pressure ratio function,
we will use an N exponent of 0.7.
Once the function has been defined,
I can return to my materials define window
and choose it from the drop down menu.
For the cyclic number function, we will estimate it using a loose said material
from the internal sample functions.
Now we will add the materials to our domain by choosing draw materials and adding the materials to each region and each analysis.
Boundary conditions can be created and assigned in a similar way as the materials.
I will choose KeyIn boundary conditions to open the define boundary conditions window.
By default, there are four boundary conditions already defined.
We will also add one more boundary condition to simulate the water reservoir on the left side of the embankment.
We will add a new stress/strain boundary condition.
We will choose the hydrostatic pressure option from the drop down menu
and assign a constant elevation of 12 m with a unit weight per unit depth of 10 kilonewtons per cubic meter.
We will then add these boundary conditions to each of our analyses.
For the initial static analysis, we will add the fixed X boundary condition to left and right boundaries,
the fixed XY boundary condition to the bottom boundary,
and the reservoir pressure to the lines representing the reservoir.
In the dynamic analysis, we will simply add the fixed y boundary condition
to the left and right boundaries
and the fixed xy boundary condition to the bottom boundary.
The initial pore-water pressure conditions will be taken from the parent static analysis.
Although we have described the hydrostatic pressure condition on the parent analysis, we still require a water table definition.
We will go to KeyIn initial water table and enter in data points representing the elevation of our water table throughout our domain.
Now our initial pore-water pressure conditions for the static analysis have been defined.
Now we will return to the dynamic analysis
to define that earthquake event.
In QUAKE/W, you can select points within your domain where results will be saved for each and
every time step while integrating through the earthquake record.
These points are called history points.
Let's define two history points: one at the top of the embankment
and one at the bottom of the profile.
History points must be applied to geometry points, so we have included a geometry point at the bottom of the profile to include it.
We will add the earthquake data by going to KeyIn horizontal earthquake records
and importing the earthquake file.
QUAKE/W is formulated on the basis of a time integration scheme.
This means that the QUAKE/W steps through the earthquake record
at a specified time interval and does a finite element analysis for each time step.
By default, QUAKE/W stores data at the 20 highest peaks of the earthquake record.
In addition, it has been specified that the data should be saved every 50th time step.
You should be aware that the more time steps you save and the more history points you select to save the motion history at, the larger your file will be.
Our next step will be to look at the default mesh.
We can see the the default global element size is set to 1 m.
More information on the meshing options can be found in the engineering books or the mesh options and constraints tutorial video.
Now we can solve all of our analyses by toggling them on in the solve manager window and clicking on the start button.
Once solved, the window will automatically change to the results view instead of the define view.
By default, the deformed mesh and pore-water pressure contours are shown on the domain.
We can click through the time steps as they are solving to see the deformation of the mesh during the dynamic earthquake analysis.
When we look at the final time step of 10 seconds, we see the final pore-water pressure contours resulting at the end of the earthquake event
along with a deformed mesh.
You can change the contours that are being shown on the domain in the results window by choosing a different contour type in the drop down menu.
You can also add new contour options by clicking on the draw contours button.
You can change the shading methods used a draw contours,
add or remove a legend,
or change the increments and starting and ending values of your contours.
Other items can be added by clicking on the add button and choosing the type of results contour you would like to create.
Contour labels can be added or removed
using the draw contour labels button.
Currently, we can see the displacement of the regions by the deformation of the mesh.
We can go to draw vectors to change the settings of the deformed mesh
or we can show the displacement using vector arrows, add velocity vectors or acceleration vectors to visualization.
You can choose what items are activated in the results window at anytime using the view
preferences toolbar along the right side of the screen.
Here you can toggle on or off results information, such as the velocity vectors, contours,
or you can view your mesh, boundary conditions, material properties,
or toggle on and off geometry items such as the regions or point numbers.
Next, we will create a graph to help us gain a better understanding of our analysis by going to draw graph.
We will add a graph showing us the relative lateral displacement
through the center of the embankment and foundation.
From the drop down menus, we will choose displacements,
relative x displacement
versus y and all time steps.
For our nodal locations, we will simply drag a box around the center nodes of the domain.
Now we can see the relative x displacements as they change over time for this vertical line.
We can rotate the graph by 90 degrees to better visualize the results with the elevation along the Y axis.
The last step of this tutorial will be to create acceleration graphs for the two history points we added to the mesh.
We will add a new graph
and choose the history points option from the drop down menu.
First we will choose the history point that is located on the top of the embankment, so we will choose this history point using set locations.
We will then choose accelerations,
X-acceleration,
versus time in the drop down menus.
For the next history point, we will simply clone the current graph,
change the name,
and use the set locations to select the history point at the bottom of the foundation.
More information on the other options available in results view can be viewed in SEEP/W,
SIGMA/W, or SLOPE/W tutorial videos.
We have now reached the end of this introductory tutorial.
Note that not all of the powerful features of QUAKE/W 2012
have been used or discussed here.
Further information on each command can be found in the online help, supporting documentation for QUAKE/W,
as well as in other tutorial videos of the Getting Started with GeoStudio video series.
Thank you for watching.