semi coupled
TRANSCRIPT
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Basic modeling concept for coupled
analysis using GTS.
Perform: Seepage Analysis (Steady-State) – Stage 1
Perform: Construction – Stage 2
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Determination of Hydraulic Head
Reference Height @ (0,0)
Height: 50 cm
Pressure head = 450 cm
Elevation head = 50 cm
Pressure head = 450 cm
Units
Force: NLength:cm
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Determination of Hydraulic
Head: Stage 1Stage Type
- Seepage Analysis (SS)
Activated Data
- Element: 50 cm- Boundary: pressure head = 450 cm
Elevation head = 50 cm
Pressure head = 450 cm
Total head = 500 cm
Define Construction Stage
**Once a defined construction stage has been
properly defined for seepage analysis, the user
must define an analysis case to instruct the
solver to consider construction stage.
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Results
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Extracting Results
440
450
460
470
480
490
500
510
0 20 40 60
Pressure Head (cm)
Pressure Head
(cm)
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Stage 2 Define Construction Stage :
Stress Analysis
Since one stage has been
defined for seepage analysis,
the user must add a “New”
stage.
In this case, the stage type will
be assigned as “Construction”
to consider the stress results.
Pore pressure results will be
automatically considered from
the previous seepage analysis
stage 1.
BC: boundary condition
SW: Self weight
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Pore Pressure Results
Pore pressure results from seepage analysis have transferred to Construction Stage.
The legend has flipped indicating that the solver has considered the results into stress analysis.
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Results
The pore pressure results from seepage analysis may not be exactly the same asthe pore pressure results that have been transferred to the stress stage. The reason
being is that the results for stress/strain values have been assigned as Center by default.
To get the exact solution, click the Center + node.
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Overview
Mesh sets
Ground
Excavation 9m, 8m,7m
Wall
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Presentation model
Wall
Several colored layers
representing
excavations
10m
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Construction Stage OverviewSemi-Coupled analysis can be modeled in GTS by interchanging the constructions
from seepage to construction stages. Interchanging the seepage stage and stress
stages can simulate the varying seepage flow and stress variations.
Semi-coupled analysis cannot consider the hydrostatic effects on the wall. In order
to simulate pressure acting on the face wall, users may consider modeling the
varying pressure loads or defining a water level function in construction stageanalysis.
**Semi-couple analysis cannot consider excess pore pressure. This can be done in
a consolidation analysis. Undrained and drained conditions can be considered.
See online help manual for instructions on defining these conditions.
Finally, a seepage face is defined along the length of the wall. This function acts as
a review boundary conditions where the solver review the total head difference
and redirects the flow path. In short, it is a boundary condition to simulate
impermeable surface. Nodal flux can also be used to simulate impermeable
permeable surfaces.
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Construction Stage 1
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Construction Stage 2
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Construction Stage 3
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Construction Stage 4
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Construction Stage 5
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Construction Stage 6
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Construction Stage 7
Total Head Stage 7
Seepage Pore pressure Stage 7
Deformation DXY
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Flow
Flow path VXY
Pore pressure last stageof excavation
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Deformation Results with and without
seepage analysis
DXY results for semi coupled analysis
: Max 6.0e-1m
DXY results for construction stage analysis
Only considering 9m water level:Max: 5.81e-1