Geo5 Engineering Manuals

7/28/2019 Geo5 Engineering Manuals

1/101


2/101

Engineering manuals for GEO5 programs

Chapter 1. Analysis settings and settings administrator 2

Chapter 2. Design of Cantilever wall 11

Chapter 3. Verification of gravity wall 22

Chapter 4. Design of non-anchored restraint retaining wall 30

Chapter 5. Design of anchored retaining wall 39

Chapter 6. Verification of retaining wall with one anchor row 44

Chapter 7. Verification of multi-anchored wall 53

Chapter 8. Analysis of slope stability 64

Chapter 9. Stability of slope with retaining wall 73

Chapter 10. Design of geometry of spread footing 82

Chapter 11. Settlement of spread footing 87

Chapter 12. Analysis of consolidation under embankment 92


3/101

2

Introduction

Engineering manuals are new teaching material for GEO5 software. They were developed as a reaction

to hotline and frequently asked questions of users. The objective of each chapter is to explain how to solve the

concrete engineering problems using GEO5 software.

Each chapter is divided to a few sections:

Introductiontheoretical introduction to the problem

Assignmenthere the problem is described with all input data needed for solving the problem in selected the

program

Solutionin this section, the problem is solved step by step

Conclusion has the conclusion of the problem and the final verification of the construction. It tells if the

structure is satisfactory or not and if there are any modifications needed.

In each chapter there are also notes, which explain the problem in general as well as links to other materials.

The basic educational materials of GEO5 software suite (from FINE s r.o.) are:

Context helpexplains the functions of the program in detail Video tutorialsshow the basic work with the software and its effective use Engineering manualsexplain how concrete engineering problems are solved Verification manualsverify the satisfaction of the results, by comparing the results from programs

with hand calculation or other programs

The first chapter explains how to set standards and chose an analysis method, which is the same for all GEO5

programs. In further chapters one standard is selected, by which the construction is verified.


4/101

3

Chapter 1. Analysis settings and settings administrator

This chapter explains the correct use of Settings administrator that serves to choose standards, partial

factors and verification methodology. It is the basic step needed for all GEO5 programs.

Introduction

GEO5 software is used in 90 countries worldwide. Engineering tasks are the same everywhere to

prove that the construction is safe and well designed.

The basic characteristic of structures (eg. geometry of wall, terrain, localization of anchors etc.) are the

same all over the world; the way of proving that the construction is safe and the theory of analysis used are

different. Large quantities of new theories and mainly partial factors of analysis lead to input of large amounts

of data and complicated programs. The Settings administrator was created in GEO5 for version 15 to simplify

this process.

In the Settings administrator are defined all input parameters, including standards, methods and

coefficients for the current country. The idea is that each user will understand the Settings defined in the

program (or will define a new Setting of analysis), which the user then uses in their work. To the Settings

administrator and Settings editor the user then goes only occasionally.

Assignment:

Perform an analysis of a gravity wall per the picture below for overturning and slip according to these

standards and procedures:

1) CSN 73 00372) EN 1997DA13) EN 1997DA24) EN 1997DA35) Safety factor on SF=1.6


5/101

4

Scheme of the gravity wall for analysis

Solution

Firstly, input the data about the construction and geological conditions in the frames: Geometry,

Assign and Soils. Skip the other frames because they are not important for this example.

Frame Geometry input of dimensions of the gravity wal


6/101

5

Table with the soil parameters

Soil

(Soil classification)

Unit weight

3mkN

Angle of

internal friction

ef

Cohesion

of soil

kPacef

Angle of friction

structure soil

MG Gravelly silt,

firm consistency19,0 30,0 0 15,0

In the frame Assign, the first soil will be assigned automatically to the layer or layers. This can be

changed when necessary.

When the basic input of construction is done, we can choose standards, and then finally run the analysis

of the gravity wall.

In the frame Settings click the button Select and choose number 8 Czech Republic old

standards CSN (73 1001, 73 1002, 73 0037).

Dialog window Settings list

Note: The look of this window depends on standards that are currently active in the Settings administrator

more information in the help of the program (press F1). If the setting you want to use isn`t on the list in the

dialog window Settings list, you can activate it in the Settings administrator.

Now, open up the frame Verification and after analyzing the example record the utilization of

construction (in the frame Verification) - 53,1% resp. 66,5%.


7/101

6

Frame Verification results of the analysis using CSN 73 0037 standard

Then return to the frame Settings and choose number 3 Standard EN 1997DA1.



8/101

7

Again, open the frame Verification and record the result (55,6% and 74,7%) for EN 1997, DA1.

Frame Verification results of analysis for EN 1997, DA1

Repeat this procedure for settings number 4 Standard EN 1997DA2 and number 5Standard

EN 1997DA3.

The analyzed utilization of constructions is (77,8% and 69,7%) for EN 1997, DA2 or (53,5% and

74,7%) for EN 1997, DA3.


9/101

8

Variant 5 (analysis using Safety factors) is not as simple. In the frame Settings click on Edit. This

will show you the current analysis settings. Change the verification methodology to Safety factors (ASD) and

then input safety factor for overturning and sliding resistance as 1.6.

Dialog window Edit current settings: Gravity wall

Press OK and run the analysis. (69,0% and 77,1%).

Frame Verification analysis results for SF = 1.6


10/101

9

If you would like to use this setting more often, it is good to save this setting by clicking on Add to

administrator, rename is as shown below, and next time use it as a standard setting.

Dialog window Add current settings to the Administrator

Dialog window Settings list then looks like this



11/101

10

Verification

Utilization in percentage using each standard is:

Overturning Slip

1) CSN 73 0037 53,1 66,52) EN 1997DA1 55,6 74,73) EN 1997DA2 77,8 69,74) EN 1997DA3 53,3 74,75) Safety factor on SF=1.6 69,0 77,1

The analysis is satisfactory using the selected analysis standards.

Note: This simple method can be used to compare retaining structures or stability analyses. When analyzing

foundations, the load (basic input data) must be computed according to relevant standards. That is the reason

why it doesnt make sense, to compare foundation design by various standards with the same values of load

(nominal values).


12/101

11

Chapter 2. Design of Cantilever wall

In this chapter, the design of cantilever wall and its overall analysis is described.

Assignment

Design a cantilever wall with a height of 4,0 m and analyze it by EN 1997-1 (EC 7-1, Design approach

1). The terrain behind the structure is horizontal. The ground water table is 2,0 meters deep. Behind the wall acts

a strip surcharge with a length of 5,0 meters and with a magnitude of 10 kN/m2. The foundation soil consists of

MSSandy silt, stiff consistency, 8,0rS , allowable bearing capacity is 175kPa. The soil behind the wall will

consist of S-F Sand with trace of fines, medium dense soil. The cantilever wall will be made of reinforced

concrete of class C 20/25.

Scheme of the cantilever wall - Assignment

Solution:

For solving this problem, we will use the GEO5 program, Cantilever wall. In this text, we will explain

solving this example step by step.

In the frame Settings click on Select and then choose analysis setting Nr. 3 Standard EN 1997

DA1.


13/101

12


In the frame Geometry choose the wall shape and enter its dimensions.

Frame Geometry


14/101

13

In the frame Material enter the material of the wall.

Frame Material Input of material characteristics of the structure

Then, define the parameters of soil by clicking Add in the frame Soils. Wall stem is normally

analyzed for pressure at rest. For pressure at rest analysis, select Cohesionless.

Dialog window Add new soils


15/101

14

Note: The magnitude of active pressure depends also on the friction between the structure and soil. The friction

angle depends on the material of construction and the angle of internal soil friction normally entered in the

interval ef 3231


Soil


Profile

m

Unit weight

3mkN

Angle of

internal

friction

ef

Cohesion

of soil

kPacef

Angle of

friction

structuresoil

S-FSand with trace of

fines, medium dense soil0,04,0 17,5 28,0 0,0 18,5

MSSandy silt, stiff

consistency, 8,0rS from 4,0 18,0 26,5 30,0 17,5

In the frame Terrain choose the horizontal terrain shape.

Frame Terrain

The ground water table is at a depth of 2,0 meters. In the frame Water select the type of water close to

the structure and its parameters.


16/101

15

Frame Water

In the next frame define Surcharge. Here, select permanent and strip surcharge on the terrain acting as

a dead load.

Dialog window New surcharge

In the frame FF resistance select the terrain shape in front of the wall and then define other parameters

of resistance on the front face.


17/101

16

Frame FF resistance

Note: In this case, we do not consider the resistance on the front face, so the results will be conservative. The

FF resistance depends on the quality of soil and allowable displacement of the structure. We can consider

pressure at rest for the original soil, or well compacted soil. It is possible to consider the passive pressure if

displacement of structure is allowed. (For more information, see HELPF1)

Then, in the frame Stage settings choose the type of design situation. In this case, it will be

permanent. Also choose the pressure acting on the wall. In our case, we will choose active pressure, as the wall

can move.

Frame Stage settings

Now, open up the frame Verification, where you analyze the results of overturning and slip of the

cantilever wall.


18/101

17

Frame Verification

Note: The button In detail in the right section of the screen opens a dialog window with detailed information

about the analysis results.

Analysis results:

The verification of slip is not satisfactory, utilization of structure is

Overturning: 52,8 % 97,10933,208 klvzd MM [kNm/m] SATISFACTORY. Slip: 124,6 % 94,8178,65 posvzd HH [kN/m] NOT OK.

Now we have several possibilities how to improve the design. For example, we can:

- Use better soil behind the wall- Anchor the base- Increase the friction by bowing the footing bottom- Anchor the stem

These changes would be economically and technologically complicated, so choose the easiest alternative. The

most efficient way is to change the shape of the wall and introduce a wall jump.

Change of the design: change of the geometry of the wall

Return to the frame Geometry and change the shape of the cantilever wall. For increasing the

resistance against slip we introduce a base jump.


19/101

18

Frame Geometry (Changing dimensions of cantilever wall)

Note: A base jump is usually analyzed as an inclined footing bottom. If the influence of the base jump

is considered as front face resistance, then the program analyses it with a straight footing bottom, but FF

resistance of the construction is analyzed to the depth of the down part of the base jump (More info in HELPF1)

Thenanalyze the newly designed construction for overturning and slip.

Frame Verification


20/101

19

Now, the overturning and slip of the wall are both satisfactory.

Then, in the frame Bearing capacity, perform an analysis for design bearing capacity

of the foundation soil 175kPa.

Frame Bearing capacity

Note: In this case, we analyze the bearing capacity of the foundation soil on an input value, which we can get

from geological survey, resp. from some standards. These values are normally highly conservative, so it is

generally better to analyze the bearing capacity of the foundation soil in the program Spread footing that takes

into account other influences like inclination of load, depth of foundation etc.

Next, in the frame Dimensioning chose wall stem check. Design the main reinforcement into the stem

6pcs. 12 mm, which satisfies in point of bearing capacity and all design principles.


21/101

20

Frame Dimensioning

Then, open up the frame Stability and analyze the overall stability of the wall. In our case, we will use

the method Bishop, which result in conservative results. Perform the analysis with optimization of circular

slip surface and then leave the program by clicking OK. Results or pictures will be shown in the report of

analysis in the program Cantilever wall.

Slope stability program

Conclusion/ Result of analysisbearing capacity:

Overturning: 49,5 % 16,10852,218 klvzd MM [kNm/m] SATISFACTORY


22/101

21

Slip: 64,9 % 47,6427,99 posvzd HH [kN/m] SATISFACTORY Bearing capacity: 86,3 00,17506,151 dR [kPa] SATISFACTORY Wall stem check: 81,5 % 88,8413,104 EdRd MM [kNm] SATISFACTORY Overall stability: 40,8 % MethodBishop (optimization) SATISFACTORY

This cantilever wall is SATISFACTORY.


23/101

22

Chapter 3. Verification of gravity wall

In this chapter an analysis of an existing gravity wall for permanent and accidental design situations is

performed. Construction stages are also explained.

Assignment

Using EN 1997-1 (EC 7-1, DA2) standard, analyze an existing gravity wall for stability, overturning, and slip .

Road traffic acts on the wall with magnitude of 10 kPa. Check the possibility to install the barrier on the top of

the wall. An accidental load from a car crash is considered as 50 kN/m and it acts horizontally at 1,0 m.

Dimensions and shape of the concrete wall can be seen in the picture below. Inclination of the terrain behind the

construction is 10 , the foundation soil consists of silty sand. The friction angle between the soil and wall

is 18 .

Determination of bearing capacity and dimensioning of the wall is not part of this task. In this analysis, consider

effective parameters of soil.

Scheme of the gravity wallassignment

Solution:

For analyzing this task, use the GEO5 programGravity wall. In this text, we will describe the steps of

analyzing this example in two construction stages.

1st construction stageanalyzing the existing wall for road traffic. 2nd construction stageanalyzing impact of vehicle to the barrier on the top of the wall.

Basic input: Stage 1


24/101

23

In the frame Settings click on Select and choose Nr. 4 Standard EN 1997DA2.


Then, in the frame Geometry, select the shape of the gravity wall and define its parameters.

Frame Geometry


25/101

24

In the next step, input the material of the wall and geological profile. Unit weight of wall is

324 mkN . Wall is made from concrete C 12/15 and steel B500. Then define parameters of soil and assign

them to the profile.


Soil


Unit weight

3mkN

Angle of

internal friction

ef

Cohesion

of soil

kPacef

Angle of friction

structuresoil

MSSandy silt,firm consistency

18,0 26,5 12,0 18,0


Note: The magnitude of active pressure depends also on friction between the structure and soil in the angle

ef 32

31 . In this case we consider the influence of friction between the structure and soil with

value of ef32 (d =18), when analyzing earth pressure. (More info in HELPF1).

In the frame Terrain select the shape of terrain behind the wall. Define its parameters, in terms of

embankment length and slope angle as shown below.

Frame Terrain

In the next frame, define Surcharge. Input the surcharge from road traffic as Strip, with its location on

terrain, and as a type of action select Variable.


26/101

25

Dialog window Edit surcharge

In the frame FF resistance choose the shape of the terrain in front of the wall and define the other

parameters of front face resistance.

Frame Front face resistance

Note: In this case, we do not consider resistance on the front face, so the results will be conservative. The FF

resistance depends on the quality of soil and allowable displacement of the structure. We consider pressure at

rest for the original soil or well compacted soil. It is possible to consider passive pressure only if displacement

of structure is allowed. (More info in HELPF1).


27/101

26

In the frame Stage settings select the type of design situation. In the first construction stage,

consider the permanent design situation.


Now open up the frame Verification, where we analyse the gravity wall for overturning and slip.

Frame Verification stage 1

Note: The button In detail in the right section of the screen opens a dialog window with detailed information

about the results of the analysis.


28/101

27

Dialog window Verification (in detail)

Note: For analyses based on EN-1997, the program determines if the force acts favorably or unfavorably. Next

each force is multiplied by the corresponding partial factor which is them on the report.

Then, open up the frame Stability and analyze the overall stability of the wall. In our case, we will use

the method Bishop, which results in conservative results. Perform an analysis with optimization of circular

slip surface and then validate everything by clicking OK. Results or pictures will be shown in the report of

analysis in the program Gravity wall.

Program Slope stability stage 1

Analysis results: Stage 1When analyzing bearing capacity, we are looking for values of overturning and slip of the wall on the

footing bottom. Then we need to know its overall stability. In our case, the utilization of the wall is:

Overturning: 70,0 % 73,26391,376 klvzd

MM [kNm/m] SATISFACTORY.

Slip: 90,6 % 17,13853,152 po svzd HH [kN/m] SATISFACTORY.

Overall stability: 72,3 % MethodBishop (optimization) SATISFACTORY.


29/101

28

Basic input: Stage 2

Now, add construction stage 2 using tool bar in the upper left corner of the screen.

Toolbar Stage of construction

In this stage, define the load from the impact of the vehicle to the barrier, using the frame

Inputforces. The load is accidental and considers the impact of a vehicle with a weight of 5 tons.

Dialog window Edit force construction stage 2 (accidental design situation)

Then open the frame Stage settings change the design situation on accidental.


The data in the other frames that we entered in stage 1 has not changed , so we dont have to open these

frames again. Select the frame Verification to perform the verification on overturning and slip again.


30/101

29

Frame Verification stage 2

Analysis results: Stage 2From the results, we see, that the existing wall is not satisfactory for impact of a vehicle to the barrier.

In this case, utilization of the wall is:

Overturning: 116,3 % 13,56862,488 klvzd MM [kNm/m] NOT OK. Slip: 102,9 % 35,14239,138 po svzd HH [kN/m] NOT OK.

Conclusion

The existing gravity wall in case of bearing capacity satisfies only for the first construction stage, where

road traffic acts. For the second construction stage, which is represented as impact to the barrier on the top of

the wall by a vehicle of 5 tons, the wall is not satisfactory.

As a solution to increase bearing capacity for overturning and slip it is possible to introduce soil

anchors. alternatively it is possible to place a barrier on the edge of the road, so the wall is not loaded by a force

from the crashing car.


31/101

30

Chapter 4. Design of non-anchored restraint retaining wall

In this chapter is the design of non-anchored retaining wall for permanent and accidental loads (flooding)

Assignment

Design non-anchored retaining wall from pile sheeting using the EN 1997-1 (EC 7-1, DA3) standard in

non-homogenous geologic layers. The depth of excavation is 2,5 m. The ground water table is at a depth of 1,0

m. Analyze the construction also for flooding; when the water is 1,0 m above the top of the wall (mobile anti-

flood barriers should be installed.)

Scheme of non-anchored wall from pile sheetingassignment

Solution:

For solving this problem, we will use the GEO5 program, Sheeting design. In this text, we will explain

each step to solve this example:

1st construction stage: permanent design situation 2nd construction stage: accidental design situation Design of geometry of the pile sheeting Analysis result (conclusion)

Basic input: Construction stage 1

In the frame Settings click on Select and then choose Nr. 5 Standard EN 1997DA3.


32/101

31


Then, input the geological profile, parameters of soil and assign them to the profile.



33/101

32


Soil


Profile

m

Unit weight

3mkN

Angle of

internal

friction

ef

Cohesion

of soil

kPacef

Angle of friction

structuresoil

S-FSand with traceof fines, medium

dense soil

0,01,5 17,5 29,5 0,0 14,0

SCClayey sand,medium dense soil

1,52,5 18,5 27,0 8,0 14,0

CL, CIClay withlow or medium

plasticity,

firm consistency

from 2,5 21,0 19,0 12,0 14,0

In the frame Geometry, select the shape of bottom of the excavation and input its depth.

Frame Geometry

Note: coefficient of reduction of earth pressure below the ditch is considered while analyzing braced sheeting

(retaining wall with soldier beams) only; for a standard sheeting pile wall it equals 1,0 For more information,

see HELP (F1).

In this case, we do not use the frames Anchors, Props, Supports, Pressure determination,

Surcharge and Applied forces. The frame Earthquake also has no influence for this analysis, because the

construction is not located in seismic-active area. In the frame Terrain, it remains horizontal.


34/101

33

In the frame Water input the GWT value 1,0 m.

Frame Water 1stconstruction stage

Then, in the frame Stage settings, select the design situation as permanent.


Now, open up the frame Analysis and click on the button Analyze. This will perform the analysis ofthe retaining wall.

Frame Analysis


35/101

34

Note: For cohesive soils is recommended by many standards to use minimal dimensioning pressure acting on

the retaining wall. The standard value for the coefficient of minimal dimensioning pressure is Ka = 0,2.

It means that minimum pressure on the structure is 0,2 of geostatic stressnever less.

Within the design of pile sheeting retaining wall, we are interested in the depth of construction in the

soil and internal forces on the structure. For the 1st

construction stage, the results of analysis are:

Length of structure: m83,4 Needed depth in the soil: m33,2 Maximum bending moment: mkNmM 21,28max,1 Maximum shear force: mkNQ 98,56max,1

In the next stage, we are going to show you how to analyse the minimum depth in soil and internal

forces in the soil for the accidental design situationfloods.

Basic inputConstruction stage 2

Now, select stage 2 on the toolbar Stage of construction on the upper left corner of your screen. (If

needed, add a new one)

Toolbar: Stage of construction


36/101

35

In the frame Water, change the GWT behind the structure to a value -1,0 m. We will not consider

water in front of the structure.

Then, in the frame Stage settings, select the design situation Accidental.



37/101

36

All other values are the same as in the 1 st construction stage, so we dont have to change data in other

frames, so we go on to the frame Analysis and click again on the button Analyze.

Frame Analysis

In the 2nd

construction stage the analysis results are:

Length of structure: m56,6 Needed depth in the soil: m06,4 Maximum bending moment: mkNmM 00,142max,2 Maximum shear force: mkNQ 17,185max,2 Using the maximum bending moment, we will design pile sheeting.

The minimum length of pile sheeting is set as the maximum of necessary length from construction stage 1

and construction stage 2 .


38/101

37

Design of pile sheeting:

We design the pile sheeting based on the maximum bending moment using the table of pile sheeting with

allowable bearing capacities shown below.

Task 'Fine - LATAM - Sending' reported error (0x80042109) : 'Outlook is unable to connect to your

outgoing (SMTP) e-mail server. If you continue to receive this message, contact your server administrator

or Internet service provider (ISP).'

Design of pile sheeting using SN EN 10 248-1 standards.

Based on the chart, we will select the pile sheeting VL 503 (500 340 9,7 mm), the steel grade S 270

GP, of which the maximum bending moment is mkNM 0,224max

.

Safe designof structure is verified by equation:

mkNmMmkNMdov 142224 max

mkNmMmkNMdov142224

max

Analysis result:

In the design of non-anchored restraint retaining wall, we are verifying values of minimum depth of the

structure in the soil, and the internal forces in the structure:

Minimum depth of the structure in first stage: 2,33 m Minimum depth of the structure in second stage: 4,06 m

So, we will design a pile sheeting with depth in the soil of 4,1 m and overall length of 6,6 meters.


39/101

38

Conclusion:

The designed pile sheeting retaining wall VL 503 from S 270 steel with length of 6,6 meters satisfies.


40/101

39

Chapter 5. Design of anchored retaining wall

In this chapter, we will show you how to design a retaining wall with one row of anchors.

Assignment:

Design a retaining wall with one anchor row made from pile sheeting using EN 1997-1 (EC 7-1, DA3)standard. The depth of ditch is 5,0 m. The anchor row is 1,5 m below the surface. The soils, geological profile,

ground water table and shape of terrain are the same as in the last task. Remove construction stage two so as

to not consider flooding.

Scheme of the anchored wall from pile sheetingassignment

Solution:

For solving this problem, we will use a GEO5 program, Sheeting design. In this text, we will explain

each step of this example:

Analysis 1: permanent design situation - wall fixed at heel Analysis 2: permanent design situation - wall hinged at heel Analysis result (conclusion)


41/101


42/101

41

In our case, we need to know the sheet pile embedment depth and also the anchor force. For the wall fixed at

heel, the values are:

Length of construction: m72,10 Depth in soil: m72,5 Anchor force: kN77,165 Maximum moment: mkNm /16,89 Maximum shear force: mkN/27,128

Now, perform an analysis for wall hinged at heel (construction stage 2). Then, compare the results

and, depending on comparison, design the embedment depth.

Basic input: Analysis 2

Now, add a new verification in the upper left corner of the frame.

Select the option Wall hinged at heel and perform the analysis.


43/101

42

Frame Analysis

For the wall hinged at heel, the values are:

Length of construction: m85,7 Depth in soil: m85,2 Anchor force: kN68,201 Maximum moment: mkNm/35,119 Maximum shear force: mkN/84,69

The results of analysis

The overall length of the structure should be in the interval of HfixedHhinged. For wall fixed at heel is

the length of the structure is longer, but the anchor force is smaller. For wall hinged at heel, it is the opposite,

so larger anchor force and shorter length of the construction. It is the users task to design the dimensions of

the structure.

Conclusion

In our design, we will use pile sheeting VL 503 from steel S 270 with an overall length of 9,0 m,

anchors with size of force 240 kN with anchor spacing of 2,5 m. In the next chapter, we will check this

structure in the program Sheeting check.


44/101

43

Note: The design cannot be taken as the final and it needs to be checked in the Sheeting check program,

because on the real structure there is redistribution of earth pressure due to anchoring.


45/101

44

Chapter 6. Verification of retaining wall with one anchor row

In this chapter, we will show you how to verify a designed retaining wall with verification of inner stability of

the anchors and overall stability of the structure.

Assignment

Verify the retaining wall that you designed in task 5.

Solution:

For solving this problem, we will use the GEO5 program, Sheeting check. In this text, we will explain

each step to solve this task:

Construction stage 1: excavation of ditch to a depth of 2,0 m + geometry of the wall Construction stage 2: anchoring of the wall + excavation of ditch to a depth of 5,0 m.


To make our work easier, we can copy the data from the last task, when we designed the wall in the

Sheeting design program by clicking in this program on Edit on the upper toolbar and selecting Copy

data. In Sheeting check program click on Edit and then Paste data. Now we have most of the important

data from the last task copied in to this program, so we dont have to input much of the needed data.

Dialog window Insert data


46/101

45

In the frame Settings, select again the number 5 Standard EN 1997, DA3. Select the analysis of

depending pressures as Reduce according to analysis settings. Leave the coefficient for minimum

dimensioning pressure as 0,20.

Frame Settings (Analysis of pressures)

Note: the selection Analysis of depending pressures do not reduce allows the analysis of limit pressures

(active and passive) without the reduction of input parameters by partial factors. This is better for estimation of

real behavior of construction. On the other hand, it does not follow EN 1997-1 Standard. (More info in HELP

F1)

Then, open up the frame Modulus hk , and choose the selection analyze Schmitt. This method

for the determination of modulus of subsoil reaction depends on the oedometric modulus and stiffness of the

structure. (More info in HELP F1)

Frame Modulus hk

Note: the modulus of subsoil reaction is an important input when analyzing a structure by the method of

dependent pressures (elastic-plastic nonlinear model). The modulus hk affects the deformation, which is

needed to reach active or passive pressures. (More info in HELP F1)

In the frame Soilsenter the following values for each soil type. Poissons ratio and the oedemetric modulus

were not entered in the previous program, so they must be entered here.


47/101

46

Soil Type


Poissons ratio

Oedometric Modulus

MPaEoed

SF - Sand with trace of fines,

medium dense0,30 21,0

SC - Clayey sand, medium dense 0,35 12,5

CL - Clay with low or medium

plasticity, firm consistency0,40 9,5

In the frame Geometry define the parameters ofthe sheet pile type of wall, section length,

coefficient of pressure reduction below ditch bottom, geometry and material of the construction. From the

sheet pile database, select the VL 503 (500 340 9,7 mm).

Dialog window Edit section


48/101

47

Now, in the frame Excavation define the first ditch depth 2,50 m for the first construction stage.

Frame Excavation

Now, go to frame Analysis. In the left part of the frame, you can see the modulus of subsoil reaction,

in the right section earth pressures and displacement. (For more information, see HELP F1)

Frame Analysis


49/101

48


Add another construction stage as indicated below. Here we define the anchoring of the wall and

overall excavation. We cannot change the frames Settings, Profile, Modulus Kh, Soils and Geometry,

because these data are the same for all construction stages. We will only change data in the frames

Excavation and Anchors.

In the frame Excavation, change the depth of the ditch to the final depth 5,0 m.

Frame Excavation

Then, go to the frame Anchors and click on the button Add. For this structure, we will add a row of

anchors to a depth 1,5 m below the top of the wall (below the surface). Also define other important

parameters: overall length of the Anchor input as 10 m, slope angle as 15 and anchor spacing as 2,5 m. Enter

a prestress force equal to 240 kN and the diameter of the anchor.

Frame Anchors


50/101

49

Note: The stiffness of the anchors is taken into account in next stages of construction. Due to the deformation

of construction the forces in anchors are changing. (More info in HELP F1).

We dont change any other input data. Now, perform the analysis to view the maximums of internal

forces and maximum displacement of the anchored structure.

Frame Analysis

Frame Analysis (Internal forces)


51/101

50

Frame Analysis construction stage 2 (Deformation and pressure on the structure)

Verification of material and cross section:

Maximum moment behind the construction is 116,03 kN/m

Sheet pile VL 503 (500 340 9,7 mm), quality of steel S 270 GP satisfies.

(Allowable moment = mkNmMmkNMu 0,1160,224 max )

Maximum displacement of structure 30,1 mm is also satisfactory.


52/101

51

Verification of anchor stability

Now, open the frame Inter. stability. You can see, that the internal stability of anchors is not satisfactory. This

means, that the anchor could tear from the soil.

.

Frame Internal stability not satisfactory result

The reason for this is that the anchor is too short, so in the frame Anchors, change its length to 12

meters. This newly designed anchor then satisfies the internal stability requirements.

Frame Internal stability satisfactory result


53/101

52

The last needed check is overall stability of the structure. Click on the button External stability. This

will open the Slope stability program. In the frame Analysis click on Analyze. We can now see, that the

slope stability is acceptable.

Frame External stability

Analysis results - conclusion:

Analysis done:

Bearing capacity of cross section:51.8 % mkNmMmkNMu 0,1160,224 max SATISFACTORY.

Internal stability: 87,5 % kNFkNFvzd 2404,274 SATISFACTORY. Overall stability: 84.8 % MethodBishop (optimization) SATISFACTORY.

In this case, the designed construction satisfies in all checked parameters.


54/101

53

Chapter 7. Verification of multi-anchored wall

In this chapter, we are showing how to design and verify a multi-anchored wall.

Assignment

Verify a multi-anchored wall made from steel soldier piles I 400 with a length of 21,0 m. Depth

of the ditch is 15,0 m. The terrain is horizontal. The surcharge acts at the surface and is permanent with

size of2

0,25 mkN . The GWT behind the construction is 10,0 m below the surface.

Scheme of the wall anchored in multiple layers

Table with the soil and rock parameters

Soil, rock

(classification)

Profile

m

Unit

Weight3mkN

Angle of

internal

friction

ef

Cohesion

of soil

kPacef

Deformation

modulus

MPaEdef

PoissonsRatio

CL, CIClaywith low or

medium

plasticity,

firm consistency

0,02,0 19,5 20 16 6,0 0,4

CSSandyclay,

firm consistency

2,04,5 19,5 22 14 7,0 0,35

R4 (good rock),

low strength4,512,0 21 27,5 30 40,0 0,3

R3 (good rock),

medium

12,016,6 22 40 100 50,0 0,25


55/101

54

strength

R5 (poor rock),

very low

strength

16,617,4

19 24 20 40,0 0,3

R5 (poor rock),

very low

strength

17,425,0

21 30 35 55,0 0,25

R5 (poor rock),

very low

strength

from 25,0 21 40 100 400,0 0,2

Angle of friction between structure and soil is 5,7 for all layers. Also, the Saturated Unit

weight equals the Unit Weight above.

Note that the Modulus of deformation is being used for soil materials.

Table with position and geometry of the anchors

Anchor

no.

Depth

mz Length

ml Root

mlk Slope

Spacing

mb Anchor force

kNF

1 2,5 19,0 0,01 15,0 4,0 300,0

2 5,5 16,5 0,01 17,5 4,0 350,0

3 8,5 13,0 0,01 20,0 4,0 400,0

4 11,0 10,0 0,01 22,5 4,0 400,0

5 13,0 8,0 0,01 25,0 4,0 400,0

All anchors have a diameter mmd 0,32 , modulus of elasticity GPaE 0,210 . Anchor

spacing is mb 0,4 .

Solution

For solving this task, use the GEO5 programSheeting Check. The analysis will be performed

in the classical way without reduction of input data so the real behavior of the structure will be

grasped. Internal stability of the anchor system and overall stability will be checked with a safety

factor of 1,5. This solution assumes you have entered the soil types and profiles, and permanent load

as listed above.

In the frame Settings select option nr. 1 Standardsafety factors.

Then, go to frame Geometry and input the basic dimensions of the section, and also the coefficient

of pressure reduction below the ditch bottom, which is in this case 0,4.


56/101

55

Dialog window New section

Note. The coefficient of reduction of earth pressures below the excavation reduces the pressures in the

soil. For classical retaining walls this is equal 1,0. For braced sheeting it is less than or equal to one.

It depends on size and spacing of braces (More info in help - F1).

Now, we will describe the building of the wall stage by stage. It is necessary to model the task

in stages, to reflect how it will be constructed in reality. In each stage it is necessary to look at values

of internal forces and deformation. If the sheeting is not stable in some stage of construction or if the

analyzed deformation is too large, then we need to change structurefor example to make the wall

embedment longer, make the ditch shallower, increase the anchor forces etc.

In construction stage 1, the ditch is made to depth of 3,0 m. In the stage 2, anchor is placed at a

depth of 2,5 m. The GWT behind the structure is at a depth of 10,0 m beneath the surface.


57/101

56

Frame Anchors Construction stage 2

In the 3rd construction stage, the ditch is excavated to a depth of 6,5 m. In the 4th stage, anchor

is placed at a depth of 5,5 m. The GWT is not changed so far.


In the 5th construction stage, the ditch is excavated to a depth of 9,0 m. In the 6th stage, anchor

is placed at the depth of 8,5 m. The depth of GWT is not changed.


58/101

57


In 7th construction stage, the ditch is excavated to a depth of 11,5 m. In 8th construction stage,

an anchor is placed at the depth of 11,0 m. The GWT in front of the wall is now at a depth of 12,0 m

below the surface. The GWT behind the structure is not changed.



59/101

58

In the 9th construction stage, the ditch is excavated to a depth of 13,5 m. In the 10th stage, an

anchor is placed at the depth of 13 m. The GWT in front of the structure is 15,5 m below the surface.


In the 11th, and last, construction stage, the ditch is excavated to a depth of 15,0 m. We will not add

new anchors. The GWT in front of the wall is at a depth of 15,5 m. Behind the wall it is at a depth of

10,0 m.


Note: Due to deformation of the structure the forces in anchors are changing. These changes depend

on the stiffness of the anchors and the deformation of the anchors head. The force can decrease (due


60/101

59

to loss of prestress force) or increase. The forces can be prestressed in any stage of construction again

to the required force.

Results of analysis

On the pictures below are the analysis results of the last, 11th construction stage.

Frame Analysis (Kh + pressures)

Frame Analysis (Internal forces)


61/101

60

Frame Analysis (Deformation + stresses)

All the stages are satisfactorily analyzedthat means that the structure is stable and functional in all

stages of the construction. The deformation must also be checked that it is not too large, as well as that

the anchor force does not exceed the bearing capacity of the anchor (The user must check this as this is

not checked by the program Sheeting check).

Maximum displacement of the wall is 28,8 mm, which is satisfactory.Note: If the program does not find a solution in some of the construction stages, then the data must be

revisede.g. to make the structure longer, make the forces in anchors larger, change the number or

position of anchors, etc.


62/101

61

Verification of cross-section of the structure

Open the frame Envelopes in the 1st construction stage, where you see the maximum and

minimum values of variables.

Maximum shear force: mkN24,237

Maximum bending moment: mkNm80,220

Frame Envelopes

The bending moment is calculated per one meter (foot) of structure, so we have to calculate the

moment acting on the soldier beam. The spacing of soldier beams in our example is 2,0 m, so the

resulting moment is 220,80 * 2,0 = 441,6 KNm.

Users can perform the verification of cross-section I 400 manually or using another program such as

FIN ECSTEEL.


63/101

62

Verificationcross-sections I 400output from FIN EC STEEL program

Overall utilization of cross-section: %8,72 Verification of bearing capacity: kNmMkNmM Ry 6,441582,606 max,

This designed cross-section satisfies analysis criteria.

Note: Dimensioning and verification of concrete and steel walls is not part of the program Sheeting

Check, but is planned for a future version.

Analysis of internal stability

Go to the frame Internal stability in the last construction stage and look at maximum allowable force

in each anchor and the specified safety factor. The minimum safety factor is 1.5.

Frame Internal stability

Note : The verification is done this way. At first we iterate the force in the anchor, resulting in an

equilibrium of all forces acting on the earth wedge. This earth wedge is bordered by construction,

terrain, the middle of the roots of anchors and the theoretical heel of structure. If an anchor is not

satisfactory the best way to resolve the issue is to make it longer or decrease the prestressed force.


64/101

63

Verification of external stability

The last required analysis is external stability. The button will automatically open the

program Slope stability, where youperform overall stability analysis.

Program Slope stability

Conclusion

The structure was successfully designed with a maximum deformation of 28,8 mm. This is

satisfactory for this type of construction. Additionally, the limits of forces in anchors were not

exceeded.

Verification of bearing capacity of cross-section - SATISFACTORY Internal stabilitySATISFACTORY

Anchor nr. 4 (analyzed safety factor): 50,1>34,5 amin SFSF .

External stabilitySATISFACORYSafety factors (Bishopoptimization): 50,1>92,2 sSFSF

The designed sheeting satisfies evaluation criteria


65/101

64

Chapter 8. Analysis of slope stability

In this chapter, we are going to show you how to verify the slope stability for critical circular

and polygonal slip surfaces (using its optimization), and the differences between methods of analysis

of slope stability.

Assignment

Perform a slope stability analysis for a designed slope with a gravity wall. This is a permanent

design situation. The required safety factor is SF = 1,50. There is no water in the slope.

Scheme of the assignment

Solution

For solving this problem, we will use the GEO5 program, Slope stability. In this text, we will

explain each step to solve this problem:

Analysis nr. 1: optimization of circular slip surface (Bishop) Analysis nr. 2: verification of slope stability for all methods Analysis nr. 3: optimization of polygonal slip surface (Spencer) Analysis result (conclusion)


66/101

65

Basic inputAnalysis 1:

In the frame Settings click on Select and choose option nr. 1 Standard safety factors.


Then model the interface layers, resp. terrain using these coordinates:

Adding interface points

Firstly, in the frame Interface input the coordinate range of the assignment. Depth of deepest

interface point is only for visualization of the exampleit has no influence on the analysis.


67/101

66

Then, input the geological profile, define the parameters of soil, and assign them to the profile.


Note: In this analysis, we are verifying the long-term slope stability. Therefore we are solving this task

with effective parameters of slip strength of soils (efef c, ). Foliation of soilsworse or different

parameters of soil in one direction - are not considered in the assigned soils.


68/101

67


Soil


Unit weight3mkN

Angle of internal

friction ef Cohesion of soil

kPacef Assigned Soil

Region

MGGravelly silt,firm consistency

19,0 29,0 8,01

S-FSand with traceof fines, dense soil

17,5 31,5 0,03

MSSandy silt, stiffconsistency, 8,0rS

18,0 26,5 16,04

Model the gravity wall as a Rigid Body with a unit weight of30,23 mkN . The slip surface

does not pass through this object because it is an area with large strength. (More info in HELP F1)

In the next step, define a surcharge, which we consider as permanent and strip with its location

on the terrain surface.

Dialog window New surcharges

Note: A surcharge is entered on 1 m of width of the slope. The only exception is concentrated

surcharge, where the program calculates the effect of the load to the analyzed profile. For more

information, see HELP (F1).


69/101

68

Skip the frames Embankment, Earth cut, Anchors, Reinforcements and Water. The

frame Earthquake has no influence on this analysis, because the slope is not located in seismically

active area.

Then, in the frame Stage settings, select the design situation. In this case, we consider it as

Permanent design situation.


Analysis 1circular slip surface

Now open up the frame Analysis, where the user enters the initial slip surface using

coordinates of the center( x, y ) and its radius or using the mouse directly on the desktopby clicking

on the interface to enter three points through which the slip surface passes.

Note: In cohesive soils rotational slip surfaces occur most often. These are modeled using circular slip

surfaces. This surface is used to find critical areas of an analyzed slope. For non-cohesive soils, an

analysis using an polygonal slip surface should be also performed for slope stability verification (see

HELPF1).

Now, select Bishop as the analysis method, and then set type of analysis as Optimization. Then

perform the actual verification by clicking on Analyze.


70/101

69

Frame Analysis Bishopoptimization of circular slip surface

Note: optimization consists in finding the circular slip surface with the smallest stabilitythe critical

slip surface. The optimization of circular slip surfaces in the program Slope stability evaluates the

entire slope, and is very reliable. For different initial slip surfaces, we get the same result for a critical

slip surface

The level of stability defined for critical slip surface when using the Bishop evaluation method is

satisfactory :

50,182,1 sSFSF SATISFACTORY.

Analysis 2:

Now select another analysis on the toolbar in upper right corner of your Analysis frame in

GEO5.

Toolbar Analysis

In the frame Analysis, change the analysis type to Standard and as method select All

methods. Then click on Analyze.


71/101

70

Frame Analysis All methodsstandard type of analysis

Note: Using this procedure, the slip surface made for all methods corresponds to critical slip surface

from the previous analysis scenario using the Bishop method. For better results the user should choose

the method and then perform an optimization of slip surfaces.

The values of the level of slope stability are:

Bishop: 50,182,1 sSFSF SATISFACTORY. Fellenius / Petterson: 50,161,1 sSFSF SATISFACTORY. Spencer: 50,179,1 sSFSF SATISFACTORY. Janbu: 50,180,1 sSFSF SATISFACTORY. Morgenstern-Price: 50,180,1 sSFSF SATISFACTORY. achuanc: 50,163,1 sSFSF SATISFACTORY.

Note: the selection of method of analysis depends on experience of the user. The most popular methods

are the method of slices, from which the most used, is the Bishop method. The Bishop method does

yield conservative results.

For reinforced or anchored slopes other rigorous methods (Janbu, Spencer and Morgenstern-Price)

are preferable. These more rigorous methods meet all conditions of balance, and they better describe

real slope behavior.

It is not needed (or correct) to analyze a slope with all methods of analysis. For example, the Swedish

method FelleniusPetterson yields very conservative results, so the safety factors could be

unrealistically low in the result. Because this method is famous and in some countries required for

slope stability analysis, it is a part of GEO5 software.


72/101

71

Analysis 3polygonal slip surface

In the last step of analysis, input the polygonal slip surface. As a method of analysis, select

Spencer, as analysis type select optimization, enter a polygonal slip surface and perform the

analysis.

Frame Analysis Spenceroptimization of polygonal slip surface

The values of the level of slope stability are:

50,158,1 sSFSF SATISFACTORY.

Note: Optimization of a polygonal slip surface is gradual and depends on the location of the initial slip

surface. This means that it is good to make several analyses with different initial slip surfaces and with

different numbers of sections. Optimization of polygonal slip surfaces can be also affected by local

minimums of factor of safety. This means the real critical surface does need to be found. Sometimes it

is more efficient for the user to enter the starting polygonal slip surface in a similar shape and place

as an optimized circular slip surface.


73/101

72

Local minimums

Note: We often get complaints from users that theslip surface after the optimization disappeared.

For non-cohesive soils, where kPacef 0 the critical slip surface is the same as the most inclined line

of slope surface. In this case, the user should change parameters of the soil or enter restrictions in

which the slip surface cant pass.

Conclusion

The slope stability after optimization is:

Bishop (circular - optimization): 50,182,1 sSFSF SATISFACTORY. Spencer (polygonal - optimization): 50,158,1 sSFSF SATISFACTORY.

This designed slope with a gravity wall satisfies stability requirements.


74/101

73

Chapter 9. Stability of slope with retaining wall

In this chapter, we are going to describe the stability analysis of an existing slope, then how to model a

sheeting wall being built, and how to check its internal and external stability.

Assignment:

Perform an analysis of an existing slope and then verify the design of an underground wall for

construction of parking areas. When performing the analysis, consider the permanent design situation

in all construction stages. Verify the stability using safety factors. The safety factor needed is

50,1sSF . All stability analyses are performed using the Bishop method with optimization of circular

slip surface.

Scheme of assignment

The wall is made from concrete class C 30/37, the thickness of the wall is mh 5,0 . The

calculated shear resistance of the wall is mkNVRd 325 .

Solution:

For solving this task, use the GEO5 programSlope Stability. In this text, we will describe the

solution of this task step by step.

Construction stage 1: slope modeling, determination of safety factor of the existing slope; Construction stage 2: making the earth cut for the parking (only as a working stage) Construction stage 3: construction of the wall, analysis of internal and external stability;


75/101

74

Analysis results (Conclusion).

Construction stage 1: slope modeling

In the frame Settings, click on Select and then choose analysis settings nr. 1 Standard safety factors.

Then, model the interface of layers, resp. terrain using these coordinates.

Interface coordinates

Note: If data is entered incorrectly, it can be undone using the button UNDO (shortcut Ctrl-Z). In the

same manner, we can use the opposite function REDO (Shortcut Ctrl-Y).

Buttons Undo and Redo


76/101

75

Then define the soil parameters and assign them to the profile.


Soil(Soil classification)

Unit weight3mkN Angle of internal

friction ef Cohesion of soil kPacef

SMSilty sand,medium dense soil

18,0 29,0 5,0

ML, MISilt with low ormedium plasticity, stiff

consistency, 8,0rS 20,0 21,0 30,0

MSSandy silt,firm consistency

18,0 26,5 12,0

In the frame Stage settings choosepermanent design situation.

Analysis 1stability of existing slope

Now open up the frame Analysis and run the verification of stability of the original slope. As

a verification method select Bishop and thenperform the optimization of circular slip surface. How

to input slip surface and optimization principle is described in more detail in the previous chapter and

in HELP (F1).


77/101

76

Analysis 1stability of the original slope

The factor of safety of the original slope as analyzed by Bishop is:

50,126,2 sSFSF Satisfactory.

Construction stage 2: earth cut modeling

Now add the second construction stage using the button in the upper left corner of the window.

Toolbar Construction stages

Add the earth cut to the interface by adding individual points of the considered earth cut (similar to

adding points to the current interface) in the frame Earth cut. The excavation for the sheeting wall is

0,5 m wide. After you are done with adding the points click on OK.


78/101

77

Coordinates of the earth cut

Note: If you define two points with same x coordinate (see picture), the program asks if you want to

add the new point to the left or right. The scheme of resulting input of the point is highlighted with red

and green color in the dialog window.

Frame Earth cut

Construction stage 3: construction of the retaining wall

Now design the sheeting wall. In the frame Embankment add the points of the interface of

the embankment. With these we actually model the face of the structure of the wall (see picture).


79/101

78

The points of embankment

Frame Embankment

Analysis 2internal stability of retaining wall

To verify the internal stability on the circular slip surface it is necessary to model the

structure as a stiff soil with fictitious cohesion, and not as rigid body. If it is modeled as a rigid body,

the slip surface cannot intersect the structure.

Note: shear resistance of the RC retaining wall is modeled with help of fictitious cohesion, which we

can determine as:

kPah

Vc Rdfict 650

5,0

0,325

where: mh width of the wall,

mkNVRd shear resistance of the wall.


80/101

79

Now return to the 1st

construction stage and add a new soil with name Material of the retaining

wall. Define the value of the fictitious cohesion as kPacef 650 , the angle of internal friction as a

small value (for example 1ef ) since the program doesnt allow to input 0. Define the unit weight

as3

25 mkN , which corresponds to structure from reinforced concrete.

Analysis 3slope stability behind the earth cut and retaining wall (internal stability)

The analysis results of internal stability show that the slope with the earth cut and the retaining

wall is stable:

50,160,1 sSFSF Satisfactory.

Analysis 3external stability of retaining wall

Now add another analysis using toolbar in the left downward corner of the program.

Toolbar More Analyses


81/101

80

Before running the analysis of the external slope stability, add restrictions on the optimization

procedure using lines that the slip surface cant intersect when it executes the optimization procedure

(More info in HELPF1). In our example the restriction lines are the same as the borders of the pile

sheeting.

Analysis 4 - restrictions on the optimization procedure

Note: for analysis of external slope stability it is appropriate to input the retaining wall as a solid

body. When the wall is modeled as a solid body, the slip surface doesnt intersect itduring the

optimization evaluation.


82/101

81

Analysis 4slope stability with earth cut and retaining wall (external stability)

From the results of external stability we can see, that the slope with the earth cut and retaining

wall is stable:

Conclusion

The objective of this chapter was to verify the slope stability and design of earth cut with

retaining wall for the construction of a car park with analysis of internal and external stability. The

results of analyses are:

This slope with earth cut and retaining wall from concrete (with width of 0,5 m) in terms of long-term

stability satisfies evaluation criteria.

Note: this designed retaining wall would need to be checked for stress from the bending moment of

loading from active earth pressure. This bending moment can be analyzed in the GEO5 programs

Sheeting design and Sheeting Check.

For the same bending moment it is also necessary to design and check reinforcementsfor example in

program FIN ECConcrete 2D.


83/101

82

Chapter 10. Design of geometry of spread footing

In this chapter, we are going to show you how to design spread footing easily and effectively.

Assignment:

Using EN 1997-1 (EC 7-1, DA1) standards, design the dimensions of a concentric spread footing. Forces

from columns act on the top of foundation. Input forces are: yxyx MMHHN ,,,, . The terrain behind the

structure is horizontal; foundation soil consists of S-FSand with trace of fines, medium dense soil. At 6,0 m is

Slightly weathered slate. The GWT is also at a depth of 6,0 m. The depth of foundation is 2,5 m below the

original terrain.

Scheme of the assignmentanalysis of bearing capacity of spread footing

Solution

For solving this problem, we will use the GEO5 program Spread footing. Firstly, we input all the data

in each frame, except Geometry. In the Geometry frame, we will then design the spread footing.

Basic input

In the frame Settings, click on Select and then choose nr. 3 Standard EN 1997DA1.


84/101

83

Frame Settings list

Also select an analysis methodin this case Analysis for drained conditions. We will not analyze

settlement.

Frame Settings

Note: Usually, spread footings are analyzed for drained conditions= using the effective parameters of soil

( efef c, ). Analysis for undrained conditions is performed for cohesive soils and short-term performance using

total parameters of soil ( uu c, ). According to EN 1997 total friction considered is always 0u .

In the next step enter the geological profile, soil parameters and assign them to the profile.

Table with the soil parameter

Soil, rock

(classification)

Profile

m

Unit weight

3mkN

Angle of internal

friction ef

Cohesion

of soil

kPacef

S-FSand with trace offines, medium dense soil

0,06,0 17,5 29,5 0,0

Slightly weathered slate from 6,0 22,5 23,0 50,0


85/101

84

In the next step, open up the frame Foundation. As a type of foundation, choose Centric spread footing and

fill in the dimensions such as depth from the original grade, depth of footing bottom, thickness of foundation

and inclination of finished grade. Also, input the weight of overburden, which is the backfill of spread footing

after construction.

Frame Foundation

Note: The depth of the footing bottom depends on many different factors such as natural and climatic factors,

hydrogeology of the construction site and geological conditions. In the Czech Republic the depth of footing

bottom is recommended to be at least 0,8 meters beneath the surface due to freezing. For clays it is

recommended that the depth be greater, such as 1,6 meters. When analyzing the bearing capacity of a

foundation, the depth of the foundation is considered as the minimal vertical distance between the footing

bottom and the finished grade.

In the frame Load enter the forces and moments acting on the upper part of foundation: yxyx MMHHN ,,,, .

These values we obtained from a structural analysis program and we can import them to our analysis by clicking

on Import.

Frame Load

Note: For design of dimensions of spread footing, generally the design load is the deciding load. , However, in

this case we are using the analysis settings EN 1997-1 - DA1, and you must enter the value of service load too,

because the analysis requires two design combinations.


86/101

85

Dialog window Edit load

In the frame Material, input the material characteristics of the foundation.

Skip the frame Surcharge, as there is no surcharge near the foundation.

Note: Surcharge around the foundation influences the analysis for settlement and rotation of the foundation,

but not bearing capacity. In the case of vertical bearing capacity it always acts favorably and no theoretical

knowledge leads us to analyze this influence.

In the frame Water enter the ground water depth as 6,0 meters.

We are not going to enter a sand gravel bed because we are considering permeable cohesionless soil at

the of footing bottom.

Then open up the frame Stage settings and select permanent as the design situation.

Design of dimensions of the foundation

Now, open the frame Geometry and apply the function Dimensions design; with which the program

determines the minimum required dimensions of the foundation. These dimensions can be edited later.

In the dialog window it is possible to input the bearing capacity of foundation soil Rd or select

Analyze. We will choose Analyze for now. The program automatically analyzes the foundation weight and

weight of soil below foundation and determines the minimum dimensions of the foundation.


87/101

86

Dialog window Foundation dimensions design

Note: Design of centric and eccentric spread footing is always performed such that that the dimensions offoundation are as small as they can be and still maintain an adequate vertical bearing capacity. The option

Input designs the dimensions of a spread footing based on the entered bearing capacity of the foundation

soil.

We can verify the design in the frame Bearing cap..

Frame Bearing capacity

Vertical bearing capacity: 97,7 % 59.53222.545 dR [kPa] SATISFACTORY.

Conclusion:

The bearing capacity of designed foundation (2,0x2,0 m) is satisfactory.


88/101

87

Chapter 11. Settlement of spread footing

In this chapter, we describe how analysis of settlement and rotation of a spread footing is performed.

Assignment:

Analyze the settlement of centric spread footing designed in last chapter (10. Design ofdimensions of spread footing). The geometry of the structure, load, geological profile and soils are the

same as in the last chapter. Perform the settlement analysis using the oedometric modulus, and

consider the structural strength of soil. Analyze the foundation in terms of limit states of

serviceability. For a structurally indeterminate concrete structure, of which the spread footing is a part,

the limiting settlement is: 0,60lim, ms mm.

Scheme of the assignmentanalysis of settlement of spread footing

Solution:

For solving this task, we will use the GEO5 programSpread footing. We will use the data

from the last chapter, where almost all required data is already entered.


89/101

88

Basic Input:

The design of spread footing in the last task was performed using the standard EN 1997, DA1.

Eurocodes do not order any theory for the analysis of settlement, so any common settlement theory canbe used. Check the setting in the frame Settings by clicking on Edit. In the tab Settlement select

the method Analysis using oedometric modulus and set Restriction of influence zone to based on

structural strength.

Dialog window Edit current settings

Note: The structural strength represents the resistance of a soil against deformation from a load. It is

only used in Czech and Slovak Republic. In other countries, the restriction of the influence zone is

described by percentage of Initial in-situ stress. Recommended values of structural strength are from

CSN 73 1001 standards (Foundation soil below the foundation)

In the next step, define the parameters of soils for settlement analysis. We need to edit each soil

and add values for Poissons ratio, coefficient of structural strength and oedometric modulus, resp.

deformation modulus.


90/101

89


Soil, rock

(classification)

Unit

weight3mkN

Angle of

internal

friction

ef

Coeff. of

structural

Strength

m

Deformation

modulus MPaEdef

Poissons

ratio

S-FSand withtrace of fines,

medium dense soil

17,5 29,5 0,3 15,5 0,3

Slightly weathered

slate22,5 23,0 0,3 500,0 0,25

Analysis:

Now, run the analysis in the frame Settlement. Settlement is always analyzed for service

load.


91/101

90

Frame Settlement

In the frame Settlement it is also needed to input other parameters:

- Initial in-situ stress in the footing bottom is considered from the finished gradeNote: the value of in-situ stress in the footing bottom has influence on the amount of settlement and the

depth of influence zonea larger initial in-situ stress means less settlement. The option of in-situ

stress acting on the footing bottom depends on the time the footing bottom is open. If the footing

bottom is open for a longer period of time, the soil compaction will be less and it is not possible to

consider the original stress conditions of the soil.

- In Reduction coefficient to compute settlement, select the option Consider foundation thicknesseffect (1).

Note: the coefficient 1

reflects the influence ofthe depth of the foundation and gives more realistic

results of the settlement

Results of analysis

The final settlement of the structure is 16,9 mm. Within an analysis of limit states of

serviceability we compare the values of the analyzed settlement with limit values, which are

permissible for the structure.

Note: The stiffness of structure (soil-foundation) has a major influence on the settlement. This stiffness

is described by the coefficient kif k is greater then 1, the foundation is considered to be stiff and

settlement is calculated under a characteristic point (located in 0,37l or 0,37b from the center of the

foundation, where l and b are dimensions of foundation). If coefficient k is lower then 1, the settlementis calculated under the center of foundation.

- Analyzed stiffness of foundation in direction is 10,137k . The settlement is computed underthe characteristic point of foundation.

Note : Informative values of allowable settlement for different kinds of structures can be found in

various standardsfor example CSN EN 1997-1 (2006) Design of geotechnical structures.


92/101

91

The Spread footing program also provides results for the rotation of the foundation, which is analyzed

from the difference of settlement of centers of each edge.

Rotation of the foundationprinciple of the analysis

Rotation in direction x : )1000(tan75,0 Rotation in direction y : )1000(tan776,1

Conclusion

This spread footing in terms of settlement satisfies evaluation criteria.

Settlement: 9,160,60lim, ssm [mm].

It is not necessary to verify rotation of this foundation.


93/101

92

Chapter 12. Analysis of consolidation under embankment

In this chapter, we are going to explain how to analyze consolidation under a constructed

embankment.

Introduction:

Soil consolidation takes into account the settlement time (calculation of earth deformation)

under the effect of external (constant or variable) loads. The surcharge leads to an increase in earth

formation stress and the gradual extrusion of water from pores, i.e. soil consolidation. Primary

consolidation corresponds to the situation in which there is a complete dissipation of pore pressures in

soil, secondary consolidation affects rheological processes in the soil skeleton (the so called "creep

effect"). This is a time-dependent process influenced by a number of factors (e.g. soil permeability

and compressibility, length of drainage paths, etc.). With regards to the degree of consolidation we

distinguish the following cases of ground settlement: final settlement corresponding to 100% consolidation from the respective surcharge partial settlement corresponding to a particular degree of consolidation from the respective

surcharge

Assignment:

Determine the settlement value under the centre of an embankment constructed

on impermeable clay one year and ten years after its construction. Make the analysis using CSN 73

1001 standards (using oedometric modulus), limit of influence zone consider using coefficient of

structure strength.

Scheme of the assignmentconsolidation


94/101

93

Solution:

The GEO 5 Settlement program will be used to solve this task. We are going to model this

example step by step:

1st construction stageinterface modeling, calculation of the initial geostatic stress. 2nd construction stageadding a surcharge by means of an embankment. 3rd up to 5th construction stagescalculation of embankment consolidation at various time

intervals (according to the assignment).

Evaluation of results (conclusion).

Basic assignment (procedure): Stage 1Check the "Perform consolidation analysis" field in the "Settings" frame. Then select specific

settings for calculation of the settlement from "Settings list". This setting describes the analysis method

for calculation of the settlement and restriction of influence zone.

Frame "Settings"

Note: This calculation considers the so called primary consolidation (dissipation of pore pressure).

Secondary settlement (creep), which may occur mainly with non-consolidated and organic soils, is not

solved within this example.

Then we enter the layer interface. The objective is to select two layers between which

the consolidation takes place.


95/101

94

Frame "Interface"

Note: If there is a homogeneous soil, then in order to calculate the consolidation, it is necessary toenter a fictitious layer (use the same parameters for the two soil layers that are separated by the

original interface), preferably at the depth of the deformation zone.

Then we define the "Incompressible subsoil" (IS) (at a depth of 10 m) by means of entering

coordinates similarly to interface modeling. No settlement takes place under the IS.

The soil parameters are entered in the next step. For soils being consolidated, it is required to

specify either the coefficient of permeability " k" or the coefficient of consolidation " vc ".Approximate values can be found in HELP (F1).

Dialog window "Modification of soil parameters"


96/101

95


Soil


Unit weight

3mkN

PoissonsRatio

Oedometric

modulus

MPaEoed

Coeff. of

structural

strength

m

Coeff. of

permeability

daymk

Clayey soil 18,5 0,3 1,0 0,1 5100,1

Embankment 20,0 0,35 30,0 0,3 2100,1

Sandy silt 19,5 0,35 30,0 0,3 2100,1

Then we assign the soils to the profile. The frame surcharge in the 1st construction stage

is not taken into consideration, since in this example it will be represented by the actual embankment

body (in stages 2 to 5). In the next step, we shall enter the ground water table (hereinafter the "GWT")

using the interface points, in our case at ground level.

In the frame Stage settings, you can only modify layout and refinement of holes, so leave the

standard settings.

The first "Calculation" stage represents the initial geostatic stress at the initial construction

time. However, it is necessary to specify the basic boundary conditions for the consolidation

calculation in further stages. The top and bottom interface of the consolidating soil is entered, as well

as the direction of water flow from this layeri.e. the drainage path.


97/101

96

"Analysis"Construction stage 1

Note: If you enter "Incompressible subsoil", you shall then consider the direction of flow of water from

the consolidating soil only upwards

Basic assignment (procedure): Stages 2 to 5Let's now move to the 2nd construction stage by tool bar at the top left of the desktop.

Toolbar Construction stage

We define the embankment itself by entering coordinates. A specific soil type is assigned to the

embankment.

"Stage 2Embankment interface points"


98/101

97

"Stage 2Embankment + Assignment"

Note: The embankment acts as a surcharge to the original ground surface. It is assumed that a well-

executed (optimally compacted) embankment theoretically does not settle. In a practice, settlement

may occur (poor compaction, soil creep effect), but the program Settlement does not address this.

In the "Analysis" frame enter the time duration of the 2nd stage corresponding to the actual

embankment construction time. The actual calculation of the settlement cannot be performed yet

because, when determining consolidation, it is first necessary to know the whole history of the

earthwork structure loading, i.e. all construction stages.

Frame "AnalysisConstruction Stage 2"


99/101

98

Since the embankment is built gradually, we are considering the linear load growth in the 2nd

construction stage. In subsequent stages, the duration of the stage is entered (1 year i.e. 365 days 3rd

stage, 10 years i.e. 3,650 days 4th stage and the overall settlement 5th stage) and the whole

loading is introduced at the beginning of the stage.

The calculations are performed after enter the last construction stage, which is on the "Overallsettlement", is turned on (you can check it at any stage apart from the first one).

Frame "CalculationConstruction Stage 5"

Analysis results

Upon the calculation of the overall settlement, we can observe partial consolidation values

below the centre of the embankment. We have obtained the following maximum settlement values in

individual construction stages:

Stage 1: only geostatic stresssettlement not calculated. Stage 2 (surcharge by embankment): for 30 days 29.2 mm Stage 3 (unchanged): for 365 days 113.7 mm Stage 4 (unchanged): for 3,650 days 311.7 mm Stage 5: the overall settlement 351.2 mm


100/101

99

"AnalysisConstruction stage 5 (Overall settlement)"

As we are interested in the embankment settlement after its construction, we will switch to theresults view in the 3rd and 4th stages (the button "Values") to "compared to stage 2" which subtracts

the respective settlement value.


101/101

"AnalysisSettlement (differences compared to previous stages)"

Conclusion:

The embankment settlement (under its centre) within one year from its construction is 84.5 mm

(= 113.729.2) and after ten years 282.5 mm (= 311.729.2).

Geo5 Engineering Manuals

Documents