vertical drain consolidation analysis with mcc model
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Vertical Drainage Consolidation Analysis with MCC Model
Soft GroundSoft Ground
Soft Ground Tutorial
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00 Vertical Drainage Consolidation Analysis with MCC ModelOverview
Banked consolidation analysis
applying drain material of both
sides drainage condi tion w ill be
performed using Modified Cam
Clay(MCC)Model.
Model the vertical drainage using
Embankment
draining boundary condition
Simulate the Initial, Embankment
and Leave stages.
Clay 1
Clay 2
The ground settlements and
excess pore pressure due to
embankment will be checked.
Clay 3
Weathered Rock
Vertical Drainage
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01Material Property
ID 1 2~4 5Ground Material Properties
Name Embankment Clay 1~3 Weathered Rock
Constitutive Model MC MCC MC
Modulus of Elasticity
[tonf/m2]3,000 300 15,000
o sson s a o . . .
Unit Weight (Y) [tonf/m3] 1.80 1.96 2.10
Saturated Unit Weight
(Ysat) [tonf/m3]1.85 2.00 2.10
Cohesion c tonf/m2 1.5 - 3.0
Internal Friction Angle () 25 - 35
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01Material Property
Ground Material Properties (MCC Properties)ID 2 3 4
Name Clay 1 Clay 2 Clay 3
Over Consolidation Ratio (OCR) 1 1 1
Slope of Normal Consolidation Line () 0.217 0.217 0.217
Slope of Over Consolidation Line () 0.043 0.043 0.043
Critical State Specific Volume () 3.579 3.817 4.928
Slope of Critical State Line (M) 0.772 0.772 0.772
Although MCC Model properties determined by triaxial compression test, which also can be estimated through
using general properties calculated by the formulations shown below in roundabout way.
303.2
c303.2
s
z e1
ln pc N ln
sin3
s n
Vertical Drainage Consolidation Analysis with MCC Model
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02Import > CAD file(*.dwg/*.dxf)Procedure
Select the SoilWorks excution
icon from the Desktop.
21
Project Manager> click Soft
Ground
Initial Parameters > click User2
1
4
Select [ton] , [m] and [day]
Main Icon > Import > select CAD
3
3
4
.
Select the Vertical Drainage
Consolidation Analysis with MCC
Model.dwg, and click [Open]
5
Unit of Force and Length are
converted automatically, but unit of
Time is not converted
5
. ,
the unit of Time when performing
the consolidation analysis.
User can copy and paste the
Vertical Drainage Consolidation Analysis with MCC Model 4
objects in CAD program directly
into SoilWorks.
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03Model > Ground Material PropertyProcedure
From Main Menu, select Model >
Ground Material Property
1
21
Refer to Step 01. to enter the
ground material properties and
click Add.
2
Click [Close]3
SoilWorks permits ground material
properties used in projects to be
compiled in a database. The
3
database is created by editing the
*.gdb file in SoilWorks/Dbase in the
Install folder.
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04Geometry > Smart SurfaceProcedure
For generating the surfaces to
assign the material properties 2
43
1
From the Main Menu, select
Geometric Shape > Auto-
generate Surfaces (command: ss)
1
From the Main Menu, select
Window > Display Settings ( )
>
2
3
5
Select Change Background
Color > Attribute Color
Click OK
4
5
Property not entered currently will
be set basically as gray and
changed as property color defined
when property data entered, which
Vertical Drainage Consolidation Analysis with MCC Model
for composite model.
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05 Assign Material PropertyProcedure
Assign the ground material property.
Refer to Page 1 to select the1
surface of Embankment, and
select Embankment under
Ground Material Property frome or s ree an rag
Drop.
1
Using the same way to assign the
property to area relevant to [clay
layer 1~clay layer 3, weathered
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06 Generate Mesh SetProcedure
Generate ground mesh sets.
From the Main Menu, select1
1
2
6
Model > Edge Seed (command :
es)
Click the Select All 2
3
Specify 0.5m as the Division
Interval
Check the location of generated
3
45
47
8
Click [OK]
From the Main Menu, select
Model > Smart Mesh command :
5
6
sm)
Check off Register each Mech Set
by Domains In case that there is no calculated element between drainage materials, mesh should be generated
for more than 3 elements to be existed at least because normal anal sis is hard to be erformed.
7
Click [OK]
Generated mesh will be registered
8
1
1 2 3 4
Vertical Drainage Consolidation Analysis with MCC Model
to Works Tree > Mesh > bottom of
mesh set with assigned name.
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O
X
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07 Define Boundary ConditionsProcedure
Define the ground supports.
From the Main Menu, select1
1
4
Loads | Boundaries > Smart
Support (command : as)
Enter the name of Boundary Set
2
Click [OK]
Define the boundary condition for
the drainage
2
3
3
From the Main Menu, selectLoads | Boundaries >
Draining Condition
4
Enter the name of Boundary Set
Select the Curve from Type
Select the line(vertical drain
5
6
7
material, both sides drain) relevant
to drain condition
Click [OK]88
6
7
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07 Define Boundary ConditionsProcedure
Define the Non-consolidation
Boundary Condition
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From the Main Menu, select
Loads | Boudnaries >Non-
Consolidation Boundary
1
2
3
4
3
Enter the name of Boundary Set
Select the Mesh from the Type
2
3
5
Select the mesh relevant to
embankment material.
Click [OK]
4
5
Define the water level
From the Main Menu, select
Loads | Boundaries >Water
6
Level
Select line placed by the water
level.
7
7
8
Vertical Drainage Consolidation Analysis with MCC Model
Click [OK]
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08 Define Construction StagesProcedure
Define the construction stages
From the Main Menu, select1
1
Analysis | Design > Construction
Stage
Click the Add Construction Stage2
2
3
4
Enter 3
Click [OK]
Select the Construction Stage 1
3
4
5
Enter Initial
Click the [Time Steps]
Create the time and number of
6
5
7
8
8
steps (Period: 1, No. of Steps: 1)
Click [OK]
Check on Water Level, and select
9
10
10
7
6
the Water Level function
Check on Initialize Displacement
Click [Modify]
1111
12 9
12
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08 Define Construction StagesProcedure
Define the time steps for each stage
Select the Construction Stage 2, and1
1
2
3
4
enter Embankment
Click the [Time Steps]
Enter Period > 45, No. of Steps > 10
2
3
Check on Save Result
Click [Create Steps]
Click [OK]
4
5
6 6
7
Click [Modify]7
The number of step is an item
defining the force increment size
Although defining more number of
step to generate the unequribrium
force can get excellent astringency,
the analysis time will be longer at the
Vertical Drainage Consolidation Analysis with MCC Model
. ,
input 300 to period, 20 to number of
step in stage of Leave.
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08 Define Construction StagesProcedure
Define the mesh set, boundary and
load set for each stage
1
From the Main Menu, select
Analysis|Design > Stage
Models 2 4
1
Select the Initial stage
Drag&Drop the Clay Layer,
Ground Support, Drainage
2
3
stage as data for adding to current
stage.
Click [Apply]4
3
A l the mesh and boundar set
of construction stage in same way.
Checking the Simulate Each
Stage, the element added/removed
Vertical Drainage Consolidation Analysis with MCC Model
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08 Define Construction StagesProcedure
Define the mesh set, boundary and
load set for each stage
3
1
Select the Embankment stage
Drag&Drop the banking material
mesh and banking
2
1
2
condition as data added to current
stage.
Click [Apply]3
In the Leave stage, there is no
add/ remove for element
4
4
A l the mesh and boundar set
of construction stage in same way.
Checking the Simulate Each
Stage, the element added/removed
Vertical Drainage Consolidation Analysis with MCC Model
can e c ec e eas y.
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09 Define Analysis CaseProcedure
Define the analysis case.
From the Main Menu, select1
71
Analysis | Design >Analysis
Case
Click [Add]2
3
4
2
Enter Consolidation Analysis
Select Construction Stage Analysis
from Analysis Method
3
46
Click [OK]
Click [Close]
5
6
Perform analysis
From the Main Menu, selectAnal sis Desi n > Anal sis
5
7
Click [Perform Analysis]8
8
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10 Analysis of Results (Settlements)Procedure
Check the settlement of ground
surface due to embankment
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Select Workstree > Results >
Leave [Time:346, Load Factor :
1.000] > Displacement > Vertical
Displacement(DZ(V))
3
1
From the Main Menu, select
Results > Result Tag ( )
Click the node on the round
2
3
1
3
surface
From the Main Menu, select
Results > Extract Result
4
5
Value ( )
Select Vertical Displacement(DZ(V))
Click [Select All ]
5
6
Select the nodes of earth surface or
enter the nodes number.
Click [Table]
7
8
6
7
Vertical Drainage Consolidation Analysis with MCC Model
Check the results
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10 Analysis of Results (Settlements)Procedure
Analyze the settlement with time
Paste the previous earth surface1
nodes result table to Excel Sheet.
Using time on step as time unit
to generate graph.
2
In consolidation analysis, because
of the settlement happened by
sperse o excess y ros a c
pressure depends on time, the
Time Step should be adjusted to
perform analysis until judging the
excess hydrostatic pressure has
been completely dispersed, in
other words the settlement of
earth surface is converged to a
Vertical Drainage Consolidation Analysis with MCC Model
certain value.
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10 Analysis of Results (Excessive Pore Pressure)Procedure
Check the excess pore pressure
due to embankment
25
Select Workstree > Results > Leave
[Time:346, Load Factor : 1.000] >
Ground Element Stresses >
Excessive Pore Pressure
1
4
3
From the Main Menu, select
Results > Result Tag ( )
Select Element from T e
2
1
Click an element
From the Main Menu, select
>
3
4
5
( )
Select Excessive Pore Pressure5
Select the nodes of earth surface or
enter the nodes number.
7
8
6
7
Vertical Drainage Consolidation Analysis with MCC Model
Check the result
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10 Analysis of Results (Excessive Pore Pressure)Procedure
Check the excessive pore pressure
with time.
Paste the previous earth surface
nodes result table to Excel Sheet.
Using time on step as time unit to2
1
.
Because of the settlement
appene y sperse o excess
hydrostatic pressure depends on
time, the Time Step should be
adjusted to perform analysis until
judging the excess hydrostatic
pressure has been completely
dispersed, in other words the
settlement of earth surface is
Vertical Drainage Consolidation Analysis with MCC Model
converged to a certain value.
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Embankment Leave
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11Analysis GuideConsolidation Analysis
Consolidation Analysis is an analysis method calculating the process that excess pore water pressure disperses depending on time in case that water resist to
external force. Because water which cannot escape due to undrained condition and resisting to load will escape slowly as time goes by through drain condition
boundary, excess pore pressure decreases over time, and internal force shared by water is transferred to be resisted by soil to raise soil deformation, also
increase the soil effective stress. The method of performing consolidation analysis can be divided into 1 one-dimensional consolidation according to theoretical
function and finite element method.
In case of one-dimensional consolidation, there is an advantage by which result can be easily obtained with simple procedure. But it is limited to two-
dimensional analysis and can not be used in general composite shape of ground analysis.
For finite element method, the limitation for shape mentioned previously or general analysis is not so much but a weakness is exist that time spent on modeling
and analysis is much. Soilworks supports both one-dimensional consolidation analysis and finite element consolidation analysis.
In consolidation analysis, elements will get DOF of pore water pressure additionally with displacement DOF at nodes.
Consolidation analysis in SoliWorks will assume all elements get DOF of pore water pressure if two kinds of boundaries, non-consolidation condition and drain
. , -
general structure element as shown below. In case of boundary happened drain in consolidation element, the drain condition must be defined. When the
boundary condition defined normally and consolidation analysis has been performed, the excess pore pressure applied non-consolidation condition and drain
condition should be 0.
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[ Boundary Condition of Consolidation Analysis ]