Hướng dẫn sử dụng phần mềm tính lún SASP help01

Save As Exit Project ID Embankment Soil Properties For Treatment Settlement Consolidation Treatment Surcharge Vertical Drain Vertical Drain and Surcharge Vertical Drain and Stage Filling

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

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

New

Input Data Calculation Option

Analysis Verify

Help About SASPro Content

Save As

Exit

Project ID Embankment Soil Properties For Treatment

Settlement Consolidation Treatment Surcharge Vertical Drain Vertical Drain and Surcharge Vertical Drain and Stage Filling

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 sub-menu CALCULATION OPTION

2.1.2 Open, Save, Save AS

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

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

You are requested to select the method of settlement calculation, theory limitation

of the compression zone and thickness of sub-layer

If option Compression curve e-logP (Default option) is selected the settlement will

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

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

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

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.

Parameters for consolidation calculation in both treated and non-treated case will

be selected from this group

The natural consolidation (consolidation without any treatment) will be calculated

if this option is checked

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

Parameters regarding under ground water will be input

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

 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

- Level from ground surface: 0m

Confirm the setting

Confirm the setting and close the form

Close the form and not apply the current setting The previous setting is valuable

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

2.2.3 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.

2.2.4 Soil Properties

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

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

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.

- 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.

- 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.

Given Soil layer

Over consolidated portion

Normal consolidated portion

Pc

Po

Layer Ac1 -Clayey soil Layer Ac2 -Clayey soil Layer As1 -SAND Layer Ac3 -Clayey soil Layer Ac4 -Clayey soil Bedrock

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

These layers belong

to the second drainage layer that can drain

up only - 1 side

- 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.

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

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

Confirm the data have been updated and close the form

Close the form without any updated data All data prior to access the form are kept unchanged

Load the common range of pressure of consolidation compression test

Testing curve

Broken line for

calculation

2.2.5 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

Three filling stage are available - see below sketch, are designed

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

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

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

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

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).

v1 (cm/day) v2 (cm/day)

2.3 ANALYSIS

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)

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

 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

The followings are typical logical errors.

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

Method of Settlement calculation based on Cc, [Cs, Pc] was selected But one and/or more of these parameters may be assigned with ZERO

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

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

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

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