QUAKE/W MODELS LIQUEFACTION AND DYNAMIC LOADING
GROUND RESPONSE ANALYSIS
QUAKE/W can simulate ground motions to evaluate dynamic stresses and strains in earth and retaining structures. This allows for assessment of liquefaction hazards and the dynamic-induced forces that can lead to instability. The dynamic stress-strain analyses can be driven by an earthquake acceleration history or by static/dynamic loads on the ground surface (e.g. blast vibration). Earthquake time-history files can be imported directly into GeoStudio and scaled to different peak accelerations for rapid sensitivity analyses. Alternatively, acceleration, velocity, or displacement data can be pasted directly into user defined spline functions. Soil and rock stress-strain responses can be represented by linear, non-linear, or equivalent linear constitutive models and retaining structures by specially formulated structural elements.
Excess pore-water pressures during an earthquake can lead to liquefaction and subsequent large-scale deformations or global failure. QUAKE/W simulates excess pore-water pressure generation using classical cyclic stress ratio and pore-water pressure relationships or by a functional relationship between volumetric straining (and therefore pore-water pressure response) to cyclic number. Liquefaction zones are identified by tracking stress paths relative to the collapse surface or by reducing effective confining stress. Liquefied zones are shown at each time step to better simulate deformations and assess stability.
STABILITY AND DEFORMATION ANALYSIS
Integration with SLOPE/W allows the factor of safety to be assessed at every dynamic analysis step using limit equilibrium or stress-based analyses. Liquefied zones identified by QUAKE/W can be assigned a steady-state strength to include the effects of strength loss. To calculate irrecoverable plastic deformation (e.g. settlement of a dam crest), use SLOPE/W with the simulated ground accelerations in a Newmark Deformation analysis. Alternatively, use SIGMA/W to compute permanent deformation by redistributing stresses within liquefied zones and other over-stressed areas. This allows for assessment of failure mechanisms and overtopping in earth structures or, when combined with structural elements, assessment of bending moments and shear stresses within retaining structures.
VIEWING THE ANALYSIS RESULTS
Once you have solved your analysis, QUAKE/W offers many tools for viewing results. Animate the motion by viewing the displacements for successive steps. Look at the complete displacement, velocity and acceleration history record at key points. Perform a spectral analysis at these points to study the ground motion frequency and seismic characteristics. Generate contours or x-y plots of stress, strain, pore-water pressure, and over 35 other parameters. Show the shaded liquefaction zone. View any stress state as a Mohr Circle with the associated space-force diagrams. Then prepare the results for your report by adding labels, axes, and pictures, or export the results into other applications such as Microsoft® Excel® for further analysis.
QUAKE/W can model the dynamic behavior of almost any earth structure, including:
- Earth embankment dams
- Natural soil and rock slopes
- Loose ground deposits
- Estimation of post-earthquake deformation
- Impact loads from dynamic blasting
- Any natural, near-horizontal ground sites with potential for excess pore-water pressure generation during earthquake shaking
- plus many more!
THE POWER OF INTEGRATION
QUAKE/W offers simple but powerful analytical capabilities when used in combination with other GeoStudio products.
- Linear analysis using linear-elastic soil properties.
- Equivalent Linear analysis, which varies soil properties for successive iterations (Damping Ratio and G-Modulus vary with cyclic strain for successive iterations).
- Generalized data point functions for specifying material properties, including functions for overburden correction function (Ks), shear stress correction (Ka), cyclic number, pore pressure, damping ratio, and G modulus reduction.
- Imported earthquake records; both horizontal and vertical acceleration vs. time records can be used.
- Scale peak acceleration and time duration of imported earthquake records for site-specific conditions.
- Boundary condition types include X and Y displacements, forces, pressures, and spring constants, as well as stress, fluid pressure, and self-weight gravity loading.
- Definition of liquefaction potential using a collapse surface and steady-state strength.
- Structural elements for soil-structure interaction; specifying both axial and flexural stiffness can affect the dynamic response of the system.
- History nodes show complete record of displacement, velocity and acceleration.
- Many ways to view results, including x-y plots, contours, deformed mesh, animation, spectral analysis, data tables, and Mohr circles.
- View most result parameters for static conditions, dynamic conditions, or both.
- View displacements, velocities and accelerations as relative values (the finite element results) or as absolute values (the results added to the earthquake record).
- And many more!
INTEGRATION WITH OTHER APPLICATIONS
USE QUAKE/W RESULTS IN A SLOPE/W STABILITY ANALYSIS
Earthquake shaking of ground structures creates inertial forces that may affect the stability of the structures. The shaking may also generate excess pore-water pressures. Both the dynamic stress conditions and the generated pore-water pressures can be taken into SLOPE/W to study how an earthquake affects the earth structure stability and deformation. SLOPE/W can perform a Newmark-type of deformation analysis to determine the yield acceleration and estimate the permanent deformation of the earth structure.
DISSIPATE EXCESS QUAKE/W PORE-WATER PRESSURES IN SEEP/W
Excess pore-water pressures generated during an earthquake can be brought into SEEP/W to study how long it will take to dissipate them.
ENGINEERING METHODOLOGY BOOK
The included QUAKE/W engineering methodology book discusses the whys and hows of modeling, as well as the theory and formulations behind the QUAKE/W product. Dynamic Modeling with QUAKE/W is a full-length book about proper modeling techniques: how to think before, during and after setting up and solving a model. The book includes chapters devoted to:
- Numerical Modeling: What, Why and How
- Geometry and Meshing
- Material Properties
- Bounday Conditions
- Analysis Types
- Functions in GeoStudio
- Numerical Issues
- Visualization of Results
- Illustration and Verification Examples
MINIMUM SYSTEM REQUIREMENTS
- Microsoft® Windows® 10, Windows® 8.1, Windows® 8, Windows® 7 SP1
- Intel® Pentium® 4 or better, or AMD Opteron™ or Athlon™ 64 or better. (GeoStudio is optimized for multi-core Intel processors)
- 1 GB hard disk space
- 1024×768 screen resolution.
For 3D features, your graphics card must support Direct3D® Feature Level 10_1 or greater.
This includes graphics cards such as (and newer than):
- Nvidia® GT 300
- ATI® Radeon® HD 4000 Series
- Intel® HD Graphics 3000/2000
- Microsoft® .NET 4.0 will be installed automatically if it is missing.
SUPPORTED VIRTUAL MACHINES
- The latest release of GeoStudio can be run on these VM platforms:
- VMware® ESXi™ 5.5 and 6.0
- VMware® Workstation™ 11 and 12
- Microsoft® Hyper-V® on Windows Server® 2016, 2012 R2, 2012, and Windows® 10
- Citrix® XenServer® 6.2, 6.5 and 7.0