Integrated into the GeoStudio Suite
QUAKE/W is integrated into the GeoStudio
suite, and therefore has access to
the GeoStudio features for creating
your model, analyzing it, and viewing results.
Dynamic Analysis of Earth Structures
QUAKE/W can be used to analyze earth structures subjected to earthquake shaking or dynamic point forces from a blast or a sudden impact load. QUAKE/W determines
the motion and excess pore-water pressures that arise due to shaking.
Therefore, it is designed primarily for assessing:
- The stability of slopes that are subjected to inertial forces arising from earthquake shaking
- The liquefaction potential of earth structures subjected to earthquake shaking
- The potential permanent deformation associated with earthquake shaking
QUAKE/W uses a finite element-based
formulation based on direct integration in the time
domain. When analyzing earth structures subjected to earthquake shaking, this
means integrating a set of time intervals from the start to the end of the
defined earthquake record. Alternative time intervals can be used for other dynamic analysis types.
QUAKE/W can model the dynamic behavior of
almost any earth structure you will encounter in your geotechnical, civil, and
mining engineering projects, including:
- Earth embankment dams
- Natural soil and rock slopes
- Loose ground deposits
- Estimation of post-earthquake
- Impact loads from dynamic blasting
- Any natural, near-horizontal ground sites with potential for excess pore water pressure generation
Constitutive Models and Material Properties
Three constitutive models are supported: Linear-Elastic, Equivalent Linear, and an effective stress
Non-Linear model. The Cyclic Stress Ratio (CSR) approach is used for
calculating excess pore-pressures arising from dynamically induced shear
Generalized material property functions
allow you to use any laboratory or published data. This includes functions for the overburden correction function (Ks), shear stress correction (Ka), cyclic
number, pore-water pressure, damping ratio, and G modulus reduction. When
QUAKE/W performs an Equivalent Linear analysis, the Damping Ratio and G modulus
vary with cyclic strain for successive iterations.
Collapse Surface Definition
A granular soil with a collapsed grain
structure can fail at strengths below its conventional strength as defined by
effective c' and φ' parameters. Using QUAKE/W, you can simulate this
liquefaction potential by defining a collapse surface and steady-state strength
for the material. QUAKE/W will use these properties to identify zones of
liquefaction within the material.
Estimate Material Properties for Typical Materials
Most material property functions can be
estimated using built-in properties for typical materials. The estimation
process requires only fundamental material information, such as the N exponent
for pore-water pressure functions, confining stress and plasticity index for
G-reduction functions, and typical soil classifications for Cyclic number
Comprehensive Range of Generalized Boundary Conditions
QUAKE/W supports a comprehensive list of
boundary condition options including normal/tangential stress, X-Y stress,
hydrostatic pressure, displacement, force, or spring boundaries. In keeping
with the entire GeoStudio suite, QUAKE/W makes broad use of generalized
functions for boundary condition definition. As such, actual field data over time or user-specified
functional relationships can be pasted into QUAKE/W. For example, acceleration or velocity data over time can be
used to create a displacement boundary function.
Insitu Condition Options
Insitu stresses can be established using
either Poisson’s ratio or by specifying an initial K
0 value for the
material. This provides the ability to model heavily over-consolidated soils in
which the horizontal stresses exceed the vertical.
Import Earthquake records
QUAKE/W allows you to import and scale earthquake
time history records. Once the horizontal or
vertical earthquake accelerations are imported, the
peak acceleration and duration can be modified in order to adjust the values
used in the QUAKE/W analysis to represent site-specific conditions.
Structural elements can in included in a
QUAKE/W analysis to investigate the effect of both axial and flexural
structural stiffness on the dynamic response of the earth structure.
Integrate with SLOPE/W for Newmark Analyses
A Newmark analysis seeks to compute the
potential permanent deformation in earth slopes arising from dynamic earthquake
forces. The QUAKE/W computed dynamic forces can be used in SLOPE/W to compute yield
accelerations and potential permanent deformations for each trial slip surface.
The stability results can be sorted to identify the trial slip surface with the
greatest potential permanent deformation.
Integrate with SLOPE/W to Model Excess Pore-Pressures and
Excess pore-pressures computed by QUAKE/W can be considered in a SLOPE/W analysis to examine the effect of the elevated pore-water pressures on stability.
Integrate with SLOPE/W to Model Liquefaction Zones
Areas indicated as potential liquefaction zones in QUAKE/W can be evaluated in a SLOPE/W analysis to assess the influence of liquefaction on stability, given the associated liquefied strength reduction factor.
Integrate with SEEP/W to Dissipate Excess Pore-Water
The time required for dissipation of excess pore-water pressures generated during an earthquake can be determined by inputting QUAKE/W results into a SEEP/W analysis.
Integrate with SIGMA/W to Model Permanent Deformation
causes large strength reductions, which may lead to permanent deformations
following an earthquake. Information on potential liquefaction zones generated
in a QUAKE/W analysis can be used to compute the degree of permanent
deformation with a stress-redistribution analysis in SIGMA/W.
Powerful Graphing and Contouring Options
Graphing is critical for the interpretation
of stress-strain problems. The powerful contouring and graphing options in
GeoStudio make it possible to plot both static and dynamic conditions such as stress,
strain, pore-water pressure, acceleration, velocity and deformation at a point
with time during the earthquake shaking. All of this data can be exported or
copy/pasted directly into spreadsheet software.
View both Relative and Absolute Results
View displacements, velocities and
accelerations as relative values (the finite element results relative to a
fixed base) or as absolute values (the results added to the earthquake record).
Relative data is used to compute, for example, excess pore-pressure, while
absolute information is used primarily to visualize the earthquake motion.
View Deformed Mesh and Liquefaction Zone
Interpretation of the results is enhanced
through the ability to view a deformed mesh, displacement vectors, and the
shading of potentially liquefiable zones. A sequence of deformed meshes over
time can be combined to make a movie of the earthquake motion.
Spectral Analysis at History Points
Look at the complete displacement, velocity
and acceleration history record at key “history” points that can be defined at
any point in the domain. Once the analysis is complete, you can perform a
spectral analysis at these points to study the ground motion frequency and
View Stresses in a Mohr Circle
A Mohr Circle and associated space-force
diagram can be plotted at any gauss point or node to further interrogate the
Sensitivity Analysis with QUAKE/W
A sensitivity analysis can be readily
conducted with QUAKE/W by cloning multiple analyses using the Analysis Tree and
then making slight changes to each one.