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Hướng dẫn sử dụng phần mềm tính lún SASP help01

TABLE OF CONTENT
1 MENU SYSTEM................................................................................................................1
2 DETAIL MENU FUNCTION...........................................................................................2
2.1 FILE..................................................................................................................................2
2.2 INPUT DATA ..................................................................................................................3
2.3 ANALYSIS.....................................................................................................................14
3 CALCULATION THEORY...........................................................................................23
3.1 PRESSURE CAUSED BY AN EMBANKMENT.........................................................23
3.2 CONSOLIDATION SETTLEMENT ............................................................................23
3.3 CONSOLIDATION........................................................................................................25
3.4 INCREASING COHESIVE STRENGTH DUE TO CONSOLIDATION.....................27

1

MENU SYSTEM
There are 4 items in the main menu and small sub-menus. Below is the appearance
of the software in running and its menu system:

File

Input Data

New

Calculation Option

Analysis
Verify

Help
About SASPro
Content


SASPro

Soft Soil Analysis Software

Save

Project ID

Settlement

Save As

Embankment

Consolidation

Exit

Soil Properties

Treatment

For Treatment

Surcharge
Vertical Drain
Vertical Drain and Surcharge
Vertical Drain and Stage Filling


2

DETAIL MENU FUNCTION

2.1

FILE

2.1.1

New
The sub-menu allows you to start a new project. It requests you to setup options
for the calculation. These requirements will be discussed more detailed in the submenu CALCULATION OPTION

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SASPro

2.1.2

Soft Soil Analysis Software

Open, Save, Save AS
These sub-menus allow you to open an existing project, save a running project as
other familiar software.

2.1.3

Print
This sub-menu allows you to print input data to a system default printer.

2.1.4

Exit
This sub-menu is to quit the program.

2.2

INPUT DATA

2.2.1

Calculation Option
This one allows you to setup options for the calculation.
Whenever you click, the following form will be appear

There are 3 option groups and 4 commands button in this form.


Group 1 - Settlement calculation model:
You are requested to select the method of settlement calculation, theory limitation
of the compression zone and thickness of sub-layer.



Settlement calculation method:
If option Compression curve e-logP (Default option) is selected the settlement will
be calculated by applying the initial formula based on the compression curve only.

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SASPro

Soft Soil Analysis Software

Otherwise, option Compression index Cc, [Cs, Pc] is selected the calculation will
be according to such properties as compression index, swell index and
consolidation stage of the soil.
See "THEORY" for more detail.


dp/po to setup compression zone:
This is the limitation at which it is assumed the settlement is so small that can be
ignored. It is referred to as settlement calculation limit in technical books.
In this software the default value is of 0.15 that is in accordance with the
Vietnamese standard.



Thickness of sub-layer:
Because the changing of the pressure caused by an embankment vs. depth,
distribution of the pressure in a layer is not constant. The thicker layer the bigger
changing of the pressure.
Settlement of a layer calculated by above equations is accurate only in case the
pressure distributed in this layer is constant. That mean, the thicker layer the larger
error will be expected in the calculation.
In order to minimize this error the layer will be divided into sub-layers with a
thickness small enough to consider that the pressure is constant in these sub-layers.
And settlement of a layer will be summed from the settlement of its sub-layers.
This is the method that has been recommended in technical books as well as
standardized in the settlement calculation.
You can select one of the values listed in the box or optionally input a number you
think it is proper.
Note:
Only 30 sub-layers in maximum are available. Thus, you could not select/input a
value smaller than 1m if there is a layer of greater than 30m in thicknesses in the
soil profile. For instance, a layer of 32m is present in the soil profile and you
selected 1m for sub-layer thickness, the following error alert will appear when the
settlement calculation is operating (Click Analysis/Settlement menu)

Reason: number of sub-layer will be (32/1=32) more than available one.

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SASPro

Soft Soil Analysis Software

In this case, 1.5m-sub-layer thickness is OK and/or you can divide this layer into
two or more layers with smaller thickness. The second alternative is strong
recommended, especially in case the stability again sliding is also considered in
design.


Group 2 - Consolidation options:
Parameters for consolidation calculation in both treated and non-treated case will
be selected from this group.



Natural consolidation:
The natural consolidation (consolidation without any treatment) will be calculated
if this option is checked.



Treatment by using:
Select this option for projects need one of the following methods for soft ground
treatment.
- Surcharge only: soft ground will be treated by surchrge only
- Vertical drain only: soft ground will be treated by sand drain and/or PVD and/or
PBD, etc.
- Vertical drain and surcharge: soft ground will be treated by vertical drain in
combination with surcharge.
- Vertical drain and stage filling: soft ground will be treated by vertical drain and
stage filling.
These options will be enable whenever the treatment option is checked.
In case one of last 3 treatment methods is selected, sub-options for these will be
enable for selection that consists of
- Ignore vertical consolidation: The vertical consolidation will be not counted in
the global consolidation if this option is checked. See "THEORY" for more detail.
- Ignore the influence of disturbance, Fs: The disturbance - smear zone due to the
vertical drain installation will be ignored if this option is checked. See "THEORY"
for more detail.
- Ignore the influence of drainage resistance, Fr: The drainage resistance of
vertical drain will be ignored if this option is checked. See "THEORY" for more
detail.



Group 3 - Under ground water:
Parameters regarding under ground water will be input.



Unit weight: 0.98 t/m3 is default value.



Level from ground surface:
Default value of 0.0m indicates the level is the ground surface. Negative value is
for the level lower than the ground surface and positive one is for higher case.

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SASPro



Soft Soil Analysis Software

Default command button:
To load the following default setting of the calculation
- Settlement calculation method: Compression curve
- dp/po: 0.15
- Sub-layer thickness: 1.0m
- Natural consolidation: Not checked
- Treatment by: Not checked
- Treatment method: Vertical drain only
- Ignore vertical consolidation: Checked
- Ignore influence of disturbance: Checked
- Ignore influence of drainage resistance: Checked
- Unit weight of water: 0.98 t/m3
- Level from ground surface: 0m



Apply command button:
Confirm the setting



OK command button:
Confirm the setting and close the form



Cancel command button:
Close the form and not apply the current setting. The previous setting is valuable.

2.2.2

Project ID
Key information of the project such as name, section, etc. will be declared and the
current setting just assigned by the calculation option will be listed in the current
setting box.
Below is the form of the menu

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SASPro

2.2.3

Soft Soil Analysis Software

Embankment
Appearance of the form will look like the two types below depend on if there is
counterweight or not - the Counterweight check box is checked or not.
All the embankment parameters are input from this form.
Note: Width, b, is only a haft width of the embankment.

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SASPro

2.2.4

Soft Soil Analysis Software

Soil Properties
There are two tabs in this form relating to the consolidation compression
properties and the other ones.

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SASPro

Soft Soil Analysis Software

All the soil properties are indicated clearly in the form. However, only properties
match with the calculation options is enabled to input.
For example
If treatment is not required - TREATED BY check box was not checked, shear
strength properties consisting of initial cohesion (Co) and ratio of increase of shear
strength (m) will be disabled.
If settlement calculation is according to compression curve - COMPRESSION
CURVE option was selected, such properties as compression index (Cc) and swell
index (Cs) will be disabled.
And so on.
Due to this, the soil properties must be confirmed again if they are sufficient or not
whenever the calculation options are changed.
Note:
- The entry "Over" is assigned to the layer that is fully or partially over
consolidated. In case of partial over-consolidation, the overburden pressure will
be compared with the pre-consolidation pressure. The layer is over consolidated
within the depth, in which the overburden pressure is greater than the given preconsolidation pressure. Conversely, it is normal consolidation - see below

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SASPro

Soft Soil Analysis Software

illustration for an actual situation of a partially over consolidated layer. This
illustration is very typical for a surface layer, in which the over consolidated
portion is the dry-crust of the layer.

Over
consolidated
portion

Pc

Given
Soil
layer
Po

Normal
consolidated
portion

- The entry "1 side" or "2 side" shall be defined based on the drainage condition
of the layer in consideration of overall drainage condition of the "drainage layer"
- see below illustration for more clearly. The average consolidation coefficient
will be calculated for each drainage layer.

Layer Ac1 -Clayey soil
Layer Ac2 -Clayey soil

These layers
belong to the first
drainage layer
that can drain up
and down - 2 sides

Layer As1 -SAND
Layer Ac3 -Clayey soil
Layer Ac4 -Clayey soil

These layers belong
to the second
drainage layer that
can drain
up only - 1 side

Bedrock
- The settlement of sandy soil in very dense condition (SPT value N ≥50) is
completely negligible and it is meaningless in the calculation and in the actual as
well. Correspondingly, ZERO will automatically assign to the settlement value of
such sandy soil. This default option can be exploited to calculate in case of that
the soft soil is fully/partially replaced by good material (sand e.g.) by assigning
N≥50 for this replaced material.

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SASPro

Soft Soil Analysis Software

- In the calculation, the value of the void ratio and coefficient of consolidation is
linearly interpolated automatically from the broken line defined by the range
inputted by the user. Correspondingly, the calculation results will be more
accurate if the broken curve is more close to the testing curve - see below
illustration for better understanding.

Testing
curve

Broken line
for
calculation

So that, the range of pressure and corresponding value of void ratio and
coefficient of consolidation is not obligatory to keep the same with the test. They
can be copied directly from the test or interpolated from the testing curve
- Zero value shall be assigned to the Ch/Cv ratio of a layer that will not be
treated. This layer will be consolidated naturally.


Update command button:
Update soil values for a layer. If the layer is listed in the list box, soil value is
updated. Otherwise the layer will be updated and added to the list.



Insert command button:
Insert a layer into the list at the cursor position. This button is enabled in the first
tab only.



Delete command button:
Erase a layer from the list at the cursor position. This button is enabled in the first
tab only.



Close command button:
Confirm the data have been updated and close the form.



Cancel command button:
Close the form without any updated data. All data prior to access the form are kept
unchanged.



Default command button:
Load the common range of pressure of consolidation compression test.

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SASPro

2.2.5

Soft Soil Analysis Software

For Treatment

All the parameters for treatment calculation are indicated clearly in the form.
However, only parameters match with the calculation options are enabled to input.
For example
If treatment method is surcharge only - TREATED BY check box was checked
and SURCHARGE ONLY option was selected, only such parameters as height of
surcharge and unit weight of the surcharge material are enabled.
Due to this, these parameters must be confirmed again if they are sufficient or not
whenever the calculation options are changed.


Filling parameters
Three filling stage are available - see below sketch, are designed.

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SASPro

Soft Soil Analysis Software

v1 (cm/day)
v2 (cm/day)
v (cm/day)
H
dt

H2
dt2

H1
dt1

It is flexible for users to design 1, 2 or 3 stage of filling with optional filling
height, speed, and stoppage for each stage.


Vertical drain parameters
There are two common types of vertical drain, sand drain and PVD, with default
diameter of 40cm and 5cm respectively, are available. But it is just in name
merely. In fact, the diameter of the vertical drain is changeable so that a new type
will be applied for calculation whenever the diameter is changed.
In case of counterweight, the designer can optionally select to improve the soil
beneath the counterweight or not, with the same or different scale in comparison
with the soil under the embankment.



Parameters for influence factors:
These data are to calculate the influence of disturbance and drainage resistance in
case of using PVD - Fs and Fr, and only the designer do not ignore these factors
that was set up in the CALCULATION OPTION menu.



Treatment boundary:
In case the soil beneath the counterweight will not be treated or treated with a
different scale in comparison with the soil under the embankment the designer can
select boundary between these treatments.



Surcharge parameters
These parameters are for calculation using surcharge.
Note: The "surcharge" entry means the load caused by the surcharge will act
immediately upon the embankment and the filling time for the surcharge height
will not be taken into account. That mean, the embankment shall be built with an
average filling speed not greater than that stipulated in the Specification (5cm/day
e.g.) up to the finished grade then full height of the surcharge can be put one time
(filling speed is not limited).

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SASPro

2.3

ANALYSIS

2.3.1

Verify

Soft Soil Analysis Software

There are two system of verification of data; one is activated directly whenever the
data are confirmed by APPLY or UPDATE or OK command button in a form Valid Data Verification System (hereinafter referred to as VDVS) and the other
that is activated only by the VERIFY menu - Logical Data Verification System
(hereinafter referred to as LDVS).


Valid Data Verification System - VDVS:
Nonnumeric values assigned for data which request numeric ones; negative values
assigned for data which request positive ones are typical errors that VDVS can
detect. VDVS is automatically activated whenever the data are confirmed.
Below is one of example of the VDVS action.

There is an invalid data in the above example, of which the ratio of dp/po was
assigned a negative value. An error message as shown above will automatically
appear to notice the user. The alert will be repeated until all the data is valid.

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SASPro



Soft Soil Analysis Software

Logical Data Verification System - LDVS
These types of error are arisen whenever inputted data do not match with the
calculation options. It is impossible for VDVS to detect this type of error. And in
most case the program still normally processes without any announcement and it
results in results not matching with the idea of the designer.
For example, at first the designer designed to improve the soft soil by sand drain
only. Then, he wants to add a surcharge to accelerate the consolidation so he
changed the calculation option. Unfortunately, he forgot to input parameters of the
surcharge (height and/or unit weight of the surcharge material) and so, the
calculation results are included the application of the surcharge but in the thinking
of the designer only.
Hence, it is strongly recommended that do spare one second for verify the data if
they are logical or not.
The error(s) if detected will be briefly listed in a box. The detail of an error will be
appeared at bottom whenever the error is selected (highlighted) by cursor. See
below form for instance.

Click REVISE command button to correct the error that is highlighted. A loop will
be repeated until all the errors are corrected and the form look like the below.

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SASPro

Soft Soil Analysis Software

The followings are typical logical errors.


Error(s) found in embankment parameters
Parameter(s) of the embankment such as Unit weight of embankment material,
height, width, etc. may be assigned with ZERO.



Error(s) found in compression parameters
Method of Settlement calculation based on Cc, [Cs, Pc] was selected. But one
and/or more of these parameters may be assigned with ZERO.



Error(s) found in shear strength parameters
Method of soft soil treatment by vertical soil drain - VSD was selected. But the
value of initial cohesion (Co) and/or factor of shear strength increase (m) and/or
pre-consolidation pressure (pc, in case of over-consolidation) may be assigned
with ZERO.



Error(s) found in surcharge parameters
Method of soft soil treatment was selected with surcharge requirement. But such
parameters as height and/or unit weight of material of the surcharge may be
assigned with ZERO.



Error(s) found in first filling stage parameters
Method of soft soil treatment by stage filling was selected. But such parameters as
height, filling speed and waiting time of first filling stage may be assigned with
ZERO.



Error(s) found in second filling stage parameters
Method of soft soil treatment by stage filling was selected. But such parameters as
height, filling speed and waiting time of second filling stage may be assigned with
ZERO.

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SASPro



Soft Soil Analysis Software

Error(s) found in Fs-calculation parameters
Influence of smear zone (Fs) will be counted into the soft soil treatment
calculation. But one and/or more of such parameters as (ds/dw), (Kh/Ks) may be
assigned with ZERO.



Error(s) found in Fr-calculation parameters
Influence of drainage resistance of PVD (Fr) will be counted into the soft soil
treatment calculation. But one and/or more of such parameters as (Kh/qw) and/or
(L) may be assigned with ZERO.

2.3.2

Settlement

The settlement is calculated for "breakpoints" - (1) center, (2) shoulder, (3) toe of
embankment and (4) shoulder, (5) toe of counterweight (in case of counterweight).
The results are tabulated and shown in tabs under the correlative name. Distance
from the center of the embankment and correlative settlement are also indicated.
Note: In case of counterweight, position of the toe of the embankment will be one
of two as below illustration, which is set up in the treatment boundary - Item 2.2.5.

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Soft Soil Analysis Software

Embankment toe
will be one of
these positions.

Click PRINT button to print out the results.
2.3.3

Consolidation
Natural consolidation (non-treated case) will be calculated if required - Item 2.2.1.
The result is as below presentation.

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SASPro

Soft Soil Analysis Software

The time necessary to achieve 95% of consolidation will be worked out. 30
intermediary points of time are automatically calculated to plot the consolidation
settlement curve vs. time smoothly.
It is also possible for the user to know the consolidation degree (U) and correlative
residual settlement (Sr) at a specific time by inputting the time in day in the box
just below the top table. Whenever the time inputted, value of U and Sr will be
indicated immediately.
The user can click the DETAIL button to view the calculation results of a selected
layer.
Summary results together with desirable U and Sr values at a specific time are
printed out by clicking PRINT button.
2.3.4

Treatment
Depending on the calculation option for treatment - if using VSD or not, the
appearance of the form of treatment calculation results will be different as follow:



Surcharge only

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SASPro

Soft Soil Analysis Software

The presentation and appearance of outputting the result is same with the case of
natural consolidation - Item 2.3.3


Other cases (VSD, VSD in combination with Surcharge or stage filling)

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Soft Soil Analysis Software

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SASPro

Soft Soil Analysis Software

Following parameters are calculated and presented and outputted:
- Total pressure,
- Effective pressure,
- Exceeded pore water pressure,
- Settlement,
- Consolidation degree,
- Settlement due to consolidation,
- Residual settlement, and
- Cohesion increase of soil due to consolidation,
All the above parameter are calculated daily for each layer and presented in the
PROGRESSING table. And the calculation results at two critical times - just
completion of the filling (END OF FILLING) and after a stoppage period (END
OF WAITING) are shown in tables of SETTLEMENT and COHESION.
The parameters are calculated:
- At the center of each layer, and
- For zones (1') under the pavement area, (2') under embankment slope area, and incase of counterweight, (3') under counterweight area and (4') under
counterweight slope area separately.
And are presented in the TAB named PAVEMENT AREA, SLOPE AREA,
COUNTERWEIGHT AREA and COUNTERWEIGHT SLOPE AREA.
Whenever the command button DETAIL is clicked, daily calculation results of a
selected layer will be presented in the table PROGRESSING and also plotted in
the next chart, in which:
- Red line: Filling,
- Black line: Cohesion,
- Blue line: Settlement, and
- Pink line: Exceeded pore water pressure.
These daily results will be outputted to a file with .prn extension by using
command button EXPORT.
Using command button PRINT prints the results at the critical times that are
presented in tables SETTLEMENT and COHESION.
Note: Pressure and settlement under a zone is average value of the pressure and
settlement respectively calculated at the breakpoint of the zone, for instance
dp(1')=[dp(1)+dp(2)]/2, Sc(1')=[Sc(1)+Sc(2)]/2 and so on - See Item 2.3.2 for
definition of breakpoints. These average values are applied to calculate the other
parameters.

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SASPro

3

Soft Soil Analysis Software

CALCULATION THEORY
Followings are the theory applied for the calculation in the software.

3.1

PRESSURE CAUSED BY AN EMBANKMENT
The pressure caused by a embankment for a point in the ground is a function of the
embankment height and coordinate of the point and is expressed by a formula as:
(3.1.1)
(3.1.2)

dp = Ip * q
q = γH

Where
γ: Unit weight of embankment material
H: Embankment height
Ip: Influence factor and is calculated or looked up according to Osterberg as
formulated and sketched below

Ip =

1
π

xα z


β + a − r 2 ( x − a − b ) 

a

(3.1.3)

b
q = γH

x

β

r

α

z

3.2

CONSOLIDATION SETTLEMENT
Consolidation settlement of a layer is calculated by summarizing the settlement of
sub-layers divided from the layer and computed according to one of two following
formula depending on the calculation option - see Item 2.3.2:

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SASPro

Soft Soil Analysis Software

If option Compression curve e-logP (Default option) is selected the settlement will
be calculated by applying the initial formula
(3.2.
1)

eo − e1i
Sc = ∑ i
hi
1 + eoi

Otherwise, option Compression index Cc, [Cs, Pc] is selected the following
formula will be applied
For over consolidation cohesive soil

Sc = ∑


Po + ∆Pi
1
Pc
hi *  Cs * lg
+ Cc * lg i
1 + eoi
Poi
Pc






(3.2.2
)

For normal consolidation cohesive soil

Po + ∆Pi 
1

Sc = ∑
hi *  Cc * lg i

1 + eoi
Pc



(3.2.
3)

Where
Sc: Consolidation settlement
Poi: Overburden pressure at the center of sub-layer (i)
∆Pi: Pressure caused by the embankment at the center of sub-layer (i)
Pc: Pre-consolidation pressure
eoi: Initial void ratio of sub-layer (i) under Poi
e1i: Void ratio of sub-layer (i) under Poi+∆Pi
Cs: Re-compression index
Cc: Compression index
hi: Thickness of sub-layer (i)
In both case the settlement of a sandy soil will be calculated according to
expression (3.2.1). The void ratio is interpolated from pressure and SPT value
according to the following chart

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SASPro

Soft Soil Analysis Software

RELATIVE CHART FOR LOAD AND VOID
RATIO OF SANDY SOIL
1

0.9

VOID RATIO e

0.8

0.7

0.6

0.5

0.4

0.3
1

10

100

1000

LOAD kg/cm

2

3.3

CONSOLIDATION
In case of vertical drains being installed, consolidation degree will be calculated
according to the Carillo formula as follow:
U = 1 − (1 − Uv ) * (1 − Ur )

(3.3.1)

Where
U: Overall consolidation degree
Uv: Vertical consolidation degree
Ur: Radial (horizontal) consolidation degree
Uv value was looked up base on the value of vertical time factor Tv that calculated
as follow:
Tv =

Cv * t
2
H

(3.3.2)

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