INVESTIGATION INTO SOME OF THE ENGINEERING PROPERTIES OF SOILS FOUND IN MOJO TOWN

ADDIS ABEBA UNIVERSITY

INSTITUTE OF TECHNOLOGY

CIVIL ENGINEERING DEPARTEMENT

INVESTIGATION INTO SOME OF THE ENGINEERING PROPERTIES OF SOILS FOUND IN MOJO TOWN

Advisor

Prof. Alemayehu Teferra A Thesis submitted to the School of Graduate Studies of Addis Ababa University in partial fulfillment of the requirements for the Degree of Masters of Science in Civil Engineering

December, 2016

Addis Ababa, Ethiopia


SCHOOL OF GRADUATE STUDIES


By

Mastewal Getahun Muluneh

December 2016

Approved by Board of Examiners

Prof. Alemayehu Teferra __________________ ______________

Advisor Signature Date

_________________ _______________

External Examiner Signature Date

__________________ ________________

Internal Examiner Signature Date

________________ _________________

Chairman Signature Date

I

DECLARATION

I, the undersigned, declare that this thesis is my original work performed under the

supervision of my research advisor Professor Alemayehu Teferra and has not been

presented as a thesis for degree in any other university. All sources of materials used for

this thesis have also been duly acknowledged.

Candidate’s name: - Mastewal Getahun Muluneh

Signature: - ________________

Place: - Addis Ababa Institute of Technology,

Addis Ababa University,

Addis Ababa.

Date of submission: - _____________

II

ACKNOWLEGEMENTS

I wish to express my sincerest gratitude to my advisor Professor Alemayehu Teferra, from

the department of Civil Engineering, Addis Ababa Institute of Technology for his

supervision and guidance throughout the research work

I would like to express my heartiest gratitude and acknowledgement to AAU school of

graduate studies, National meteorological service agency of Ethiopia, Municipality office

of Mojo Town and Abyssinia College for providing necessary material in the research

work.

I also would like to thank all my crew members for their committed and render assistance

in field work of this thesis.

Last, but most certainly not least, I wish to express my gratitude to my family for their

constant encouragement and support over the years. I must express my appreciation to

my Wife, Nestanet Abebaw of who gave me the push to complete this research work.

III

TABLE OF CONTENTS

DECLARATION ................................................................................................................ I

ACKNOWLEGEMENTS .................................................................................................. II

TABLE OF CONTENTS ................................................................................................. III

LIST OF TABLES ........................................................................................................... VI

LIST OF FIGURES ........................................................................................................ VII

LIST OF EQUATION .................................................................................................... VIII

LIST OF SYMBOLS AND ABBREVIATIONS ................................................................. IX

ABSTRACT ..................................................................................................................... X

1. INTRODUCTION ...................................................................................................... 1

1.1 Back ground of the problem ............................................................................... 1

1.2 Objective of the study ......................................................................................... 2

1.3 Materials and Methodology ................................................................................ 2

1.4 Scope of the study ............................................................................................. 3

1.5 Structure of the thesis ........................................................................................ 3

2. LITERATURE REVIEW ............................................................................................ 4

2.1 Soil formation and Deposit ................................................................................. 4

2.1.1 Parent material ............................................................................................ 4

2.1.2 Topography ................................................................................................. 4

2.1.3 Time............................................................................................................. 4

2.1.4 Climate ........................................................................................................ 4

2.2 General types of soils ......................................................................................... 5

2.2.1 Types and method of soil classification ....................................................... 5

2.2.2 Typical values of water content for various types of natural soils in a saturated state ......................................................................................................... 5

2.2.3 General ranges of specific gravity ............................................................... 6

2.2.4 Ranges of Values of Unit Weight of typical soils .......................................... 7

2.2.5 Free swell for determination of degree of expansion of soils ....................... 8

2.2.6 Typical values of liquid, Plastic, and shrinkage limits for soil minerals and soil deposits. ............................................................................................................ 9

2.2.7 Impact of soil type on position and shape of compaction curve ................. 10

2.2.8 General characteristics of unconfined compression strength of cohesive soil 11

IV

3. DESCRIPTION OF THE STUDY AREA ................................................................. 13

3.1 General ............................................................................................................ 13

3.2 Soil and Geology .............................................................................................. 15

3.2.1 Soil ............................................................................................................ 15

3.2.2 Geology ..................................................................................................... 15

3.3 Topography and drainage conditions ............................................................... 15

3.4 Climate ............................................................................................................. 16

3.4.1 Rainfall....................................................................................................... 16

3.4.2 Temperature .............................................................................................. 17

4. IN-SITU PROPERTIES AND LABORATORY TESTS RESULTS .......................... 18

4.1 In- situ properties ............................................................................................. 18

4.1.1 Identification of soil in the study area ......................................................... 18

4.1.2 In-situ properties Description ..................................................................... 20

4.2 Index property .................................................................................................. 22

4.2.1 General ...................................................................................................... 22

4.2.2 Specific gravity .......................................................................................... 22

4.2.3 Particle size distribution ............................................................................. 24

4.2.4 Atterberg limits ........................................................................................... 28

4.2.5 Free swell .................................................................................................. 30

4.3 Classification of soils ........................................................................................ 32

4.3.1 General ...................................................................................................... 32

4.3.2 Classification based on Unified soil classification (USC) system ............... 32

4.4 Geotechnical map of Mojo town ....................................................................... 36

4.5 Compaction ...................................................................................................... 38

4.5.1 General ...................................................................................................... 38

4.5.2 Test procedure and Results ....................................................................... 38

4.6 Direct Shear ..................................................................................................... 41

4.6.1 General ...................................................................................................... 41


4.7 Unconfined Compression ................................................................................. 42

4.7.1 General ...................................................................................................... 42


4.8 Consolidation ................................................................................................... 43

4.8.1 General ...................................................................................................... 43

V

4.8.2 Test Procedure and Results ...................................................................... 44

4.8.3 Pre Consolidation Pressure ....................................................................... 46

4.8.4 Coefficient of consolidation (𝐶𝑉) ................................................................ 47

4.8.5 Compression Index (𝐶𝐶) ............................................................................ 49

4.8.6 Coefficient of Permeability ......................................................................... 51

5. DISCUSSION AND COMPARISON ....................................................................... 53

5.1 Discussion of laboratory results ....................................................................... 53

5.2 Comparison of results with previous researches .............................................. 54

6. CONCLUSION AND RECOMMENDATION ........................................................... 55

6.1 Conclusion ....................................................................................................... 55

6.2 Recommendation ............................................................................................. 56

REFERENCES .............................................................................................................. 57

APPENDIX – A: Test Pits logs ...................................................................................... 60

APPENDIX – B: Meteorological data............................................................................. 66

APPENDIX – C: Grain size analysis test results ........................................................... 70

APPENDIX – D: Atterberg limits test results ................................................................. 76

APPENDIX – E: Compaction test results ...................................................................... 90

APPENDIX – F: Direct shear test results ...................................................................... 98

APPENDIX – G: Unconfined Compression test results ............................................... 101

APPENDIX – H: Consolidation test results .................................................................. 108

VI

LIST OF TABLES

Table 2. 1 Typical values of water content in a saturated state [5] .................................. 6

Table 2. 2 Specific gravity of minerals [25] ...................................................................... 6

Table 2. 3 Typical values of specific gravity of various soils [8] ....................................... 7

Table 2. 4 Ranges of Values of Unit Weight of typical soils [4] ....................................... 8

Table 2. 5 Free swell for determination of degree of expansion of soils [29] ................... 8

Table 2. 6 Values of Atterberg Limits for soil minerals and soil Deposits [25] ................. 9

Table 2. 7 General relation between consistency and unconfined compression strength

of cohesive soil [5] ......................................................................................................... 12

Table 4. 1 Global coordinates of sampling areas .......................................................... 18

Table 4. 2 The In-situ density and natural moisture contents of soil samples. .............. 21

Table 4. 3 Specific gravity of soil of the research area .................................................. 23

Table 4. 4 summary of grain size analysis results ......................................................... 26

Table 4. 5 Summary of liquid limit and plastic limit and the calculated plastic index ..... 29

Table 4. 6 Free Swell result of the study area ............................................................... 31

Table 4. 7 Classification of soil based on Unified Soil Classification System (USCS) ... 34

Table 4. 8 Summary of optimum moisture content and maximum dry density. ............. 39

Table 4. 9 summary of shear stress parameters ........................................................... 41

Table 4. 10 Unconfined Compression Test Results of Undisturbed Soil sample Mojo

Town ............................................................................................................................. 43

Table 4. 11 Summary of consolidation test results ........................................................ 50

Table 4. 12 calculated value of coefficient of permeability ............................................ 52

Table 5. 1 Discussion of Laboratory and field test results ............................................. 53

Table 5. 2 Comparison of test results of Mojo Town ..................................................... 54

VII

LIST OF FIGURES

Figure 2. 1 Casagrande PI-LL Chart (1948) [32] ........................................................... 10

Figure 2. 2 Typical Compaction Curve For range of soil type [22] ................................. 10

Figure 2. 3 Typical appearance of failed specimens after unconfined compressive

strength testing [5] ......................................................................................................... 11

Figure 3. 1: Location of the research area on the of Ethiopia ........................................ 14

Figure 3. 2 Mean Annual Rain fall of Mojo Town (1982-2011 ....................................... 16

Figure 3. 3: Average Monthly Maximum and Minimum temperature distribution of Mojo

Town. (1983-2011) ........................................................................................................ 17

Figure 4. 1 Test Pit Location on Mojo town map ........................................................... 19

Figure 4. 2 Combined Grained size analysis curve ....................................................... 27

Figure 4. 3 Plasticity chart of the study area according to USCS .................................. 35

Figure 4. 4 Geotechnical Map of Mojo Town ................................................................. 37

Figure 4. 5 Summary of compaction curve .................................................................... 40

Figure 4. 6 Effective vertical stress vs. void ratio on semi log scale .............................. 44

Figure 4. 7 Effective vertical stress vs. void ratio on linear scale .................................. 45

Figure 4. 8 Method of determining Pc by Casagrande method ..................................... 46

Figure 4. 9 Typical void ratio vs. pressure curve to determine 𝑃𝑐 ................................. 47

VIII

LIST OF EQUATION

Equation 4. 1 Formula for Calculaion for over consolidation ratio ................................. 46

Equation 4. 2 Formula for Calculation for coefficient of consolidation based on square

root of time fitting method ............................................................................................. 48

Equation 4. 3 Formula for Calculation for coefficient of consolidation based on logarithm

of time fitting method ..................................................................................................... 48

Equation 4. 4 Formula for Calculation for compression index ....................................... 49

Equation 4. 5 Formula for Calculation for coefficient of permiability ............................. 51

Equation 4. 6 Formula for Calculation for coefficient of comprressibility ....................... 51

IX

LIST OF SYMBOLS AND ABBREVIATIONS

𝛾𝑑 - Dry unit weight

𝛾𝑤 - Wet unit weight

AASHTO - American Association of Highway and Transportation Office

ASTM - American Society for Testing Materials standard

LL - Liquid Limit

m.a.s.l - Above mean sea level

MDD - Maximum Dry Density

MH - Inorganic Elastic Silt

ML - Inorganic Silt

NMC - Natural moisture content

OMC - Optimum moisture content

PI - Plastic Index

PL - Plastic Limit

SM - Silty sand

SP - Poorly graded sand

TP - Test Pit

UCS - Unconfined Compressive Strength

USCS - Unified Soil Classification System

X

ABSTRACT

Today Mojo has expanded considerably with new buildings, railways, roads, industries

and dry port. Therefore, a better understanding of the subsoil is required. It is also worth

mentioning that, Mojo is located in the rift valley of Ethiopia thus placing it in seismic active

zone. According to EBCS 8, 1995 the city is located in zone four

This research work is carried out to investigate the static engineering properties of Mojo

Town. To achieve this objective, soil samples were collected throughout the town and

laboratory and field tests were conducted.

According to results of the field test, the in-situ density ranges from 1.40 to 1.70g/cm3

and the dry density have a value from 1.12 to 1.61g/cm3.

From the grain size analysis result, the soil of the town has clay content ranging from

10.03 to 32.32%, silt fraction from 36.82 to 80.65%, sand fraction 5.77 to 92% and gravel

content from 0.0 to 18.77%.

The Atterberg limit test on the research area showed a liquid limit range from 29 to 87%,

plastic limit ranging from 18 to 50% and plastic index from 11 to 46%.

The specific gravity ranges from 2.62 to 2.70 and the Free swell ranges from 20 to 60%.

From the compaction test result the maximum dry density (MDD) of Mojo soil ranges from

1.15 to 1.83 g/cm3 and the optimum moisture content ranges from 14.57 to 44.33 %.

According to Unified Soil Classification System (USCS), The research area shows wide

range of category which include silt, silt with sand, sand and sandy silt with gravel

From the Direct shear test results which is conducted on representative samples collected

the research area have angle of internal friction ranging from 120 to 290

From the unconfined compression tests, Mojo soil unconfined compressive strength (qu),

ranges from 135 to 179 kPa, Undrained Shear Strength (cu), ranges from 68 to 90 kPa

XI

Finally, from consolidation tests the soil in the research area is over consolidated in its

natural state with compression index ranging from 0.3 to 0.32, coefficient of consolidation

ranging from 0.24 to 0.82 𝑐𝑚2 𝑠𝑒𝑐⁄ and coefficient of permeability ranging from 1.83 to

23.47𝑥10−5 𝑐𝑚 𝑠𝑒𝑐⁄

1

1. INTRODUCTION

1.1 Back ground of the problem

Geotechnical investigations are executed to acquire information regarding the physical

characteristics of soil and rocks which are further used to design structures that are

founded on them.

An adequate ground investigation is an essential component in the execution of civil

engineering projects. Sufficient information must be obtained to enable a safe and

economic design to be made and to avoid difficulties during construction. The principal

objectives of the investigation are: (1) to determine the sequence, thicknesses and lateral

extent of the soil strata and, where appropriate, the level of bedrock; (2) to obtain

representative samples of the soils (and rock) for identification and classification and, if

necessary, for use in laboratory tests to determine relevant soil parameters;(3) to identify

the groundwater conditions. The investigation may also include the performance of in-situ

tests to assess appropriate soil characteristics. The results of a ground investigation

should provide adequate information, for example, to enable the most suitable type of

foundation for a proposed structure to be selected and to indicate if special problems are

likely to arise during excavation [34].

Insufficient geotechnical investigations, faulty interpretation of results, or failure to portray

results in a clearly understandable manner may contribute to inappropriate designs,

delays in construction schedules, expensive construction modifications, use of

substandard borrow material, environmental damage to the site, post construction

remedial work, and even failure of a structure and subsequent litigation [38].

To have economical and durable structures, geotechnical investigation in the engineering

properties of soil is vital. Data which are gathered from the investigation are essential in

design of foundation, retaining structures and other different structure which are to be

constructed in the future.

Fewer researches were undertaken and there are ongoing researches on static properties

of silty soils: Investigation on some of the engineering characteristics of soils in Adama

2

town, Ethiopia [7], Investigation on some of the engineering properties of Bishoftu town

soil, Ethiopia [16].

1.2 Objective of the study

To investigate some of the engineering and index properties of Mojo soil like:

Natural moisture content, field density, specific gravity, consistency limits, Grain

size analysis and soil classification with an appropriate soil map of the town.

To determine the range of values of index property of soil in different parts of the

town.

To determine the shear strength and compressibility characteristics of soils for

selected sites.

1.3 Materials and Methodology

The following methods were employed to achieve the objectives of this research:

Preliminary information about formation of soils have been gathered.

Disturbed and undisturbed samples have been collected and transported to Addis

Ababa University for laboratory testing.

GPS reading have been taken to locate the ordinate of the sampling area.

Visual classification, field density, natural moisture content tests have been done.

Shear strength, compaction, consolidation, consistency limit, specific gravity, free

swell and gradation tests have been conducted.

Classification of soil based on index properties and Soil map of the area have been

done.

The results of the tests have been interpreted and conclusions has been made.

3

1.4 Scope of the study

The scope of the study is limited to investigation of index properties, shear strength and

compaction characteristic. Due to the budget constraint, the depth of the investigation is

limited to maximum of three meters.

1.5 Structure of the thesis

This thesis consists of six Chapters, each covering a specific topic of the research work.

In this introductory Chapter the background of the problem, objective and scope,

methodology of the thesis work and structure of the thesis are presented. Chapter two

deals with a brief literature review, Chapter three deals with the description of the study

area. In-situ properties with sample description, the types of laboratory tests conducted,

results obtained and tentative soil map of Mojo Town based on primary and secondary

data are present in Chapter four. The discussion on the laboratory results obtained from

this work and comparison with previously done researches indicated in Chapter five.

Chapter six includes the conclusions and recommendations drawn from the research.

Finally, summary of test results, meteorological data and soil profile for each test pits are

included in appendix.

4

2. LITERATURE REVIEW

2.1 Soil formation and Deposit

2.1.1 Parent material The formation of soils commences by chemical alteration and physical disintegration of

rocks at their exposed surface. These rocks are termed as parent material. The parent

material has the greatest influence on the incipient soils in the early stages of soil

formation and in the drier regions but lessens over time as other soil forming factors

become more active. There are a variety of parent materials as there are a variety of rock

types with different mineral phases and chemical composition. As the parent materials

minerals undergo weathering, they exchange material with the environment through

chemical reactions forming new minerals and assimilate water, gases and organic matter.

Gerrard (2000) states concisely that parent material influences soils through the process

of weathering and subsequently through the weathered material [15].

2.1.2 Topography Topography is important in soil formation as it exercises a significant control on surface

processes like erosion and drainage [15]. It also controls the effective age of the profile

by controlling the rate of erosion of weathered material from the surface [13]. Different

topographic terrains with different landscapes uniquely affect soil development [15].

2.1.3 Time Time is a critical factor in soil formation as it determines the degree to which other factors

either undergo change or are able to express themselves. The thickness of the soil layer

and the chemical changes that have taken place depend upon, amongst others, on the

time the soil forming processes have been occurring [15].

2.1.4 Climate Climate exerts a considerable influence on the rate of weathering. Physical weathering is

more predominant in dry climates while the extent and rate of chemical weathering is

largely, controlled by the availability of moisture and by temperature. (Other things being

equal, chemical reaction rates approximately double for each increase 100c in average

temperature) [13].

5

2.2 General types of soils

2.2.1 Types and method of soil classification

It has been discussed earlier that soil is formed by the process of physical and chemical

Weathering. The individual size of the constituent parts of even the weathered rock might

range from the smallest state (colloidal) to the largest possible (boulders). This implies

that all the weathered constituents of a parent rock cannot be termed soil. According to

their grain size, soil particles are classified as cobbles, gravel, sand, silt and clay. Grains

having diameters in the range of 4.75 to 76.2 mm are called gravel. If the grains are visible

to the naked eye, but are less than about 4.75 mm in size the soil is described as sand.

The lower limit of visibility of grains for the naked eyes is about 0.075 mm. Soil grains

ranging from 0.075 to 0.002 mm are termed as silt and those that are finer than 0.002

mm as clay. This classification is purely based on size which does not indicate the

properties of fine grained materials [31].

Soils are classified as coarse grained, granular, and cohesionless if the amount of gravel

and sand exceeds 50 percent by weight or fine grained and cohesive if the amount of

fines (silt and clay-size material) exceeds 50 percent.

For engineering purposes, there are two major systems that are presently used. They

are: (i) the American Association of State Highway and Transportation Officials

(AASHTO) Classification System and (ii) the Unified Classification System. [5] But Soil is

classified by geotechnical engineers for engineering purposes in accordance with the

Unified Soil Classification System (USCS) [27].

2.2.2 Typical values of water content for various types of natural soils in a saturated state

Most natural soils, which are sandy and gravelly in nature, may have water contents up

to about 15 to 20%. In natural fine-grained (Silty or clayey) soils, water contents up to

about 50 to 80% can be found. However, peat and highly organic soils with water contents

up to about 500% are not uncommon [5]. Typical values of water content in a saturated

state are presented in Table 2.1.

6

Table 2. 1 Typical values of water content in a saturated state [5].

Soil

Natural water content in a

saturated state (%)

Loose uniform sand 25 - 30

Dense uniform sand 12 - 16

Loose angular-grained Silty sand

25

Dense angular-grained Silty sand

15

Stiff clay 20

Soft clay 30 - 50

Soft organic clay 80 - 130

2.2.3 General ranges of specific gravity

Specific gravity of soil solids is controlled by soil mineralogy. In coarse-grained soils such

as sands and gravels, where the mineralogy is dominated by quartz and feldspar, Gs is

typically around 2.65. In fine-grained soils, Gs is more variable due to the presence of

clay minerals, and may range from 2.70-2.85 [27]. General range of specific gravity of

mineral [25] are shown in Table 2.2. Whereas specific gravity of different types of soils [8]

are shown in Table 2.3.

Table 2. 2 Specific gravity of minerals [25]

Mineral Specific gravity

Quartz 2.65

K-feldspars 2.54-2.57

Na-Ca-feldspars 2.62- 2.76

Calcite 2.72

Dolomite 2.85

Muscovite 2.7- 3.2

Biotite 2.8-3.2

Chlorite 2.6-2.9

Pyrophyllite 2.84

Serpentine 2.2- 2.7

Kaolinite 2.62- 2.66

Halloysite 2.55

Illite 2.60-2.86

Montmorillonite 2.75-2.78

Attapulgite 2.3

7

Table 2. 3 Typical values of specific gravity of various soils [8]

2.2.4 Ranges of Values of Unit Weight of typical soils

Unit weight of soil is an important parameter in Design and Construction of structures that

bears on soil. The value of unit weight of soil is considerably smaller in loose state and

when the soil is submerged. However Coarser and well graded soils exhibit larger unit

weight Values. Table 2.4 Shows Ranges of values of unit weight of typical soils in there

loose and dense state [4].

Types of soil Specific gravity

Inorganic Gravel 2.65

Coarse and medium sand 2.65

Fine sand (Silty) 2.65

Loess, rock flour, sandy silt 2.67

Inorganic Slightly clayey sand 2.65

Sandy silt 2.66

Silt 2.67-2.70

Clayey sand 2.67

Clayey sandy silt 2.67

Clayey silt 2.68

Sand-clay 2.68

Sand- silt-clay 2.69

Silt—clay 2.71

Sandy clay 2.7

Silty clay 2.75

Lean clay 2.75

Clay 2.72-2.8

Organic Silts with traces of organic matter 2.3

Organic alluvial muds 2.13-2.60

Peat 1.50-2.15

8

Table 2. 4 Ranges of Values of Unit Weight of typical soils [4]

Unit Weight (kPa)

Soil type State of soil Dry

In-Situ Saturated Buoyant

Sandy gravel Loose 14 - 17 18 – 20 18 - 21 8 - 11

Dense 19 – 21 20 – 23 21 – 23 12 - 14

Coarse sand, medium sand Loose 13 - 15 16 - 19 17 - 19 8 - 10

Dense 17 - 18 18 - 21 20 -21 10 - 11

Uniform fine sand Loose 14 - 15 15 - 19 19 - 20 9 - 10

Dense 17 - 18 18 - 21 21 – 22 11 - 12

Coarse silt Loose 13 - 15 15 - 19 19 - 20 8 - 10

Dense 16 - 17 17 - 21 20 - 21 10 – 11

Silt Soft 13 - 15 16 - 20 18 - 20 8 - 10

Slightly plastic 16 - 17 17 - 21 20 - 21 10 – 11

Hard 18 – 19 18 – 22 21 – 22 12 – 13

Lean Clay Soft 13 - 14 16 - 18 18 - 19 8 - 9


Hard 18 – 19 18 – 22 21 – 22 12 – 13

Fat clay Soft 9 – 15 12 - 18 16 - 22 6 - 12


Hard 18 – 20 17 – 22 22 – 24 12 – 14

2.2.5 Free swell for determination of degree of expansion of soils

Free swell is used to measure the expansive nature of cohesive soil. Soils with free swell

index greater than 50% is termed as expansive [17]. Table 2.5 Shows degree of

expansion of soils according to free swell index value [29].

Table 2. 5 Free swell for determination of degree of expansion of soils [29]

Free Swell index Degree of Expansion

> 200 Very High 100 – 200 High 50 – 100 Medium < 50 Low

9

2.2.6 Typical values of liquid, Plastic, and shrinkage limits for soil minerals and soil deposits.

Liquid limit typically ranges anywhere from 20% for silts to over 100% for high-plasticity

clays. Plasticity index typically ranges anywhere from near 0% (i.e.; a non-plastic soil)

for silts to over 50% for high-plasticity clays [27]. Table 2.6 shows values of Atterberg

limits for soil minerals and soil deposits. And figure 2.1 shows mineral composition of soils

on Casagrande PI-LL Chart [25,32].

Table 2. 6 Values of Atterberg Limits for soil minerals and soil Deposits [25].

Soil Type Liquid Limits (LL) Plastic Limits (PL) Shrinkage limits (SL)

Montmorillonite [28] 100-900 50-100 8.5-15

Illite [28] 60-120 35-60 15-17

Kaolinite [28] 30-110 25-40 25-29

Ethiopian [26] 63-108 - 4-9

Ethiopia Red Clay [39] 44-66 - -

Ethiopian black [39] 37-88 - 7-28

Adama silt and Silty sand [7] 29-73 21-39 -

Gondor Black Soils [1] 58-110 14-37 3-32

Addis Ababa red clay [37] 56-76 24-34 14-22

Mekelle black soil [23] 49-90 14 -28 4-16

Bahir Dar red clay soil [12] 61-68 34-38 14-17

10

Figure 2. 1 Casagrande PI-LL Chart (1948) [32].

2.2.7 Impact of soil type on position and shape of compaction curve

The soil type will have dramatic effects on the shape of a compaction curve achieved. In

general, coarser materials will have a higher maximum dry density and lower optimum

water content than soils with fine - grained components. In addition, well - graded coarse

materials will have well defined peaks, while uniform coarse - grained materials will be

flatter, and may not even have a peak. Figure 2.2 shows typical compaction curves for a

range of soil types [22].

Figure 2. 2 Typical Compaction Curve For range of soil type [22]

11

Additional observations, after compacting eight soils according to the standard proctor

methods and examining the water content-dry density relationships. Johnson and

Sallberg, 1960, conclude the following points.

Coarse-grained soils, well graded, compacted to high dry unit weights, especially

if they contain some fine. However, if the quantity of fines is excessive, maximum

dry unit weight decrease.

Poorly graded or uniform sands lead to the lowest dry unit weight values

In clay soils, the maximum dry unit weight tends to decrease as plasticity increase

Cohesive soils have generally high values of OMC

Heavy clays with high plasticity have very low maximum dry unit weight and very

high OMC.

2.2.8 General characteristics of unconfined compression strength of cohesive soil

Unconfined compressive strength of fine-grained soils may range from a few Pascal for

soft, normally consolidated clays, to over 50 kilo Pascal’s for dry compacted specimens.

For stiffer specimens, a failure plane may be apparent within the specimen, oriented at

an angle of approximately 45 degrees (Figure 2.3 (a)). Softer specimens are less likely

to exhibit a distinct failure plane, and are more likely to demonstrate “barreling” behavior

(Figure 2.3 (b)). Typical appearance of failed specimens after unconfined compressive

strength testing is shown in Figure 2.3. Table 2.7 shows general relation between

consistency and unconfined compression strength of cohesive soil [5].

Figure 2. 3 Typical appearance of failed specimens after unconfined compressive strength testing [5]

12

Table 2. 7 General relation between consistency and unconfined compression strength of cohesive soil [5].

Consistency qu (kN/m2)

Very soft 0-24

Soft 24-48

Medium 48-96

Stiff 96-192

Very stiff 192-383

Hard >383

13

3. DESCRIPTION OF THE STUDY AREA

3.1 General

Mojo is a town located in the central Ethiopia, named after Mojo river, located in Misrak

Shewa zone of the Oromia region 70km east of Addis Ababa and about 26kms to west of

Adama town, it is located 80 35’ N latitude and 390 07’ E latitude.it is an administrative

center of Lome Woreda. Mojo is not only accessible by road but also has served as a

train station of Addis Ababa –Djibouti railway line since 1915 [41].

Mojo has an estimated total population of 39,316 of whom 19,278 were males and 20,038

were female [10]. It is also worth mentioning that, Mojo is located in rift valley of Ethiopia

thus placing it in a seismic active zone. According to EBCS 8, 1995 the city is located in

zone four. The location of the research area on the map of Ethiopia is shown in Figure

3.1.

14

Figure 3. 1: Location of the research area on the of Ethiopia

15

3.2 Soil and Geology

3.2.1 Soil

According to [33] there are three types of soils observed in the town and its surrounding:

I. Vertisols (black cotton) found in the central, south and south western part of

the town.

II. Sandy and Silty soils: - these soils are observed in different colors in the areas

of the town i.e. light brown, dark brown and red. Although clay soils are found

in these category Silty clays, sandy silt and loam soil which is the combination

of clay and silt are the main components of these soils. These soils are found

in north eastern, eastern and central part of the town.

III. Alluvium: - the main compositions of these soils are sandy silt, sandy clay and

flood plain. These deposits are found in the southern, northern and eastern part

of the town.

3.2.2 Geology

Mojo and its surrounding areas are supposed to have been covered by the ancestral lake

during the pluvial period of the Quaternary [33].

Currently in the areas of Mojo Town the lacustrine sedimentation is found. These

lacustrine sediments are the redeposit of volcanic sands, silt stone, sand stone, and

diatomite with intercalations of water-laid tuff [33].

3.3 Topography and drainage conditions

The topography of Mojo town ranges from 1730 to 1890 m.a.s.l. in the northern part of

the town. The southern part of the town is the area around the highway towards

Shashemane. From this highway, the general characteristic of the terrain decreases in

elevation towards Mojo River. On the other hand the South-eastern part of the town is

ascending in elevation around Ethiopian Road Authority camp. In the western and the

central part of the town the topography of the terrain is plain except in gorges of Mojo

river, where there is descending in elevation. In the eastern direction, the topography is

16

plain but the peripheral area of the land is ascending in elevation from Malk- Lami towards

Tedde high lands [33].

Because of the topographic configuration of the town and its environment, the alignment

of flow of the Mojo River is from north western to the south eastern direction of the town.

Mojo town is located in Awash drainage basin [33].

3.4 Climate

3.4.1 Rainfall

The records of National Meteorological Service Agency from Adama Observatory

Substation show that the Mean Annual rainfall for 29 years i.e. from 1982 to 2011 is shown

in Figure 3.2

Figure 3. 2 Mean Annual Rain fall of Mojo Town (1982-2011

0

10

20

30

40

50

60

70

80

90

100

Jan Feb March April May Jun July Aug Sep Oct Nov Dec

Rai

n f

all (

mm

)

Month

17

3.4.2 Temperature

In a mountainous tropical country like Ethiopia, altitude is by far the most important factor

controlling climate. It affects distribution of both temperature and rain fall. Generally,

regions between 1500-2300 m.a.s.l. (categorized as ‘woina dega’ or subtropical climates)

have a temperature that ranges between 15 – 20oC, areas between 500 - 1500 m.a.s.l

(i.e. ‘kola’ or tropical climate) have 20 – 30oC area below 500 m.a.s.l. (‘bereha’ or desert

climate) have a temperature of 30oC and above.

The town of Mojo, with altitude ranging from 1730 – 1890 m.a.s.l., has a mean minimum,

mean maximum and mean average monthly temperatures of 11.8, 28.6 and 20.2 oC

respectively. The highest temperature is during months of March, April, May and June

where October, December and January have low temperature. From Figure 3.4 the mean

monthly average temperature ranges from 18.3oC to 22.3oC. This shows the temperature

variation is almost the same throughout the year.

Figure 3. 3: Average Monthly Maximum and Minimum temperature distribution of Mojo Town. (1983-2011)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Ave

rage

te

mp

ratu

re

Months

TMAX

TMIN

18

4. IN-SITU PROPERTIES AND LABORATORY TESTS RESULTS

4.1 In- situ properties

4.1.1 Identification of soil in the study area

Before selecting sampling areas, aerial photograph, visual site investigation and

information from resident and construction firms were collected to consider the different

soil types and to take sample evenly in the whole town. Accordingly, nine sampling areas

were selected from different locations of the town. Pits were excavated to a maximum of

three meters. Both disturbed and undisturbed samples were taken except for test pit 3

because of sandy nature of the soil which make recovering of undisturbed sample difficult.

In the field visual soil description was made and sample for laboratory testing were

collected. The global coordinates of sampling are shown in Table 4.1, Figure 4.1 shows

Test Pit locations on Mojo Map and Test Pits logs according to EBCS designation is

shown in Appendix A.

Table 4. 1 Global coordinates of sampling areas

Test Pit Location Northing (m) Easting (m) Elevation (m)

TP-1 High School 948,948.88 514,325.32 1787

TP-3 Elementary school 950,387.55 514,007.82 1795

TP-4 Daema School 949,583.88 513,683.70 1777

TP-5 Beza school 950,384.90 513,038.78 1774

TP-6 TVET 949,911.30 514,434.46 1788

TP-7 Catholic church 949,977.44 513,290.13 1779

TP-8 Dry Port 948,442.80 516,134.27 1802

TP-9 TK Church 952,662.06 511,156.86 1791

TP-10 CCF 945,179.46 511,206.30 1759

19

Figure 4. 1 Test Pit Location on Mojo town map

20

4.1.2 In-situ properties Description

4.1.2.1 Natural moisture content

Natural moisture content is defined as the moisture content of undisturbed soil in-situ.

The consistency of a fine-grained soil largely depends on its water content. The

water content is also used in expressing the phase relationships of air, water, and

solids in a given volume of soil [24].

Since it was difficult to bring undisturbed sample that can preserve the natural moisture

content to the laboratory, this test was performed by taking polyethylene bag and balance

to the field.in the site the weight of the moist soil is measured then the sample was brought

to the laboratory and put it in to drying oven at a temperature of 105+5 oC for 24 hours.

Then the natural moisture content is determined. Table 4.2 shows the natural moisture

content of nine test pits

4.1.2.2 In situ Density

This test was done according to standard reference: ASTM D 4914 Standard Test for

density in place by the sand replacement Method. Table 4.2 shows field density at three

meters

21

Table 4. 2 The In-situ density and natural moisture contents of soil samples.

Test pit designation

Depth (m) Natural

moisture content (%)

In-situ density (g/cm3)

Dry density (g/cm3)

TP-1

0.00-0.20 Fill -

0.20-1.40 28.24 - -

1.40-3.00 25.87 1.49 1.19

TP-3 0.00-1.50 31.56 - -

1.50-3.00 5.29 1.7 1.61

TP-4

0.00-0.40 Fill - -

0.40-1.55 31.62 - -

1.55-3.00 35.85 1.57 1.16

TP-5

0.00-1.10 30.1 - -

1.10-1.80 25.94 - -

1.80-3.00 32.18 1.5 1.14

TP-6 0.00-1.50 21.58 - -

1.50-3.00 24.97 1.4 1.12

TP-7 0.00-1.20 24.96 - -

1.20-3.00 23.88 1.47 1.19

TP-8

0.00-1.50 17.68

1.50-2.00 29.17

2.00-3.00 28.82 1.47 1.17

TP-9

0.00-1.25 26.17

1.25-2.00 27.77

2.00-3.00 29.49 1.41 1.14

TP-10 0.00-1.50 26.02

1.5-3.00 17.27 1.49 1.18

22

4.2 Index property

4.2.1 General

As an aid for the soil and foundation engineer, soils have been divide into basic categories

based upon certain physical characteristics and properties. The categories have been

relatively broad in scope because of the wide range of characteristics of the various soils

that exist in nature. For a proper evaluation of the suitability of soil for use as foundation

or construction material, information about its properties, in addition to classification, is

frequently necessary. Those properties which help to assess the engineering behavior of

a soil and which assist in determining its classification accurately are termed ‘Index

Properties’. Generally, index properties are the properties of soil that help in identification

and classification of soil [6, 40].

4.2.2 Specific gravity

4.2.2.1 General

Specific gravity of soil solids, Gs, is the mass density of the mineral solids in soil

normalized relative to the mass density of water. Alternatively, it can be viewed as the

mass of a given volume of soil solids normalized relative to the mass of an equivalent

volume of water [27].

The Values of Gs for majority of soil lies between 2.65 - 2.8. Lower values are for coarse-

grained soils. The presence of organic matter leads to very low values. Soils high in iron

or mica exhibits high values [14]. This implies the specific gravity of the minerals affects

the specific gravity of soils derived from them [31].

4.2.2.2 Test procedure and results

The procedure followed to run this test is according to ASTM standard with designation

ASTM D 854-98. There are two methods available for determining the specific gravity

Method A and Method B, Method A, this procedure is for moist specimen of organic soils;

highly plastic, fine grained soils; tropical soils; and soils containing halloysite on the other

hand Method B is used for oven dried specimen.

23

For the aforementioned Reason Method A is use for determination of specific gravity in

this research work. The test results are shown in Table 4.3. From the table we observe

that within the depth of exploration the specific gravity Ranges from 2.62 to 2.7

Table 4. 3 Specific gravity of soil of the research area

Test pit Depth (m) Specific Gravity

Water used

TP-1

0.00-0.20 Fill NA

0.20-1.40 2.63 Tap water

1.40-3.00 2.68 “

TP-3 0.00-1.50 2.69 “

1.50-3.00 2.64 “

TP-4

0.00-0.40 Fill NA

0.40-1.55 2.65 Tap water

1.55-3.00 2.7 “

TP-5

0.00-1.10 2.64 “

1.10-1.80 2.64 “

1.80-3.00 2.67 “

TP-6 0.00-1.50 2.66 “

1.50-3.00 2.63 “

TP-7

0.00-1.20 2.65 “

1.20-3.00 2.67 “

0.00-1.50 2.67 “

TP-8

1.50-2.00 2.66 “

2.00-3.00 2.65 “

0.00-1.25 2.63 “

TP-9 1.25-2.00 2.62 “

2.00-3.00 2.63 “

0.00-1.50 2.64 “

TP-10

2.00-3.00 2.63 “

24

4.2.3 Particle size distribution

4.2.3.1 General

The soil grading or the distribution of particle size is quantitatively determined by

performing the particle-size analysis, also called mechanical analysis, which is carried out

in two parts: sieve analysis and sedimentation analysis. The distribution of gravel and

sand particles is determined by sieve analysis and that of silt and clay by sedimentation

analysis. Depending on the type of soil and the extent of particle-size distribution required,

mechanical analysis may involve both sieving and sedimentation or it may be restricted

to either of them. For gravel and sand, sieve analysis alone will suffice, but if silt and clay

are present, a combined sieve and sedimentation analysis may be required. If soil is

predominantly Silty and or clayey, sedimentation alone will do.

In this research work the analysis is done by wet sieve for composition analysis of both

Sieve and hydrometer

4.2.3.2 Test procedure and results The procedure followed to run this test is according to ASTM standard with designation

D-422-63 and D-1140-97

In this thesis both dry and wet sieve is used, the procedure for wet sieve is as followed,

first the samples collected from the site were air dried and representative sample were

taken by quartering. The existing moisture content of the air dried sample was measured

which was used for hydroscopic correction. The weight of the sample was measured and

after it was washed on sieve No. 200 mechanical sieve was done on sample of soils

retained on sieve No. 200, after drying it for 24 hours. The sample of soil that pass No.

200 was transferred to large dish and soaked until the water becomes clean, then the

clean water was decanted. After the sample has dried in room temperature, it’s pulverized

and 500 grams of soil was taken for hydrometer test. In case of dry sieve representative

25

sample were taken by quartering, and mechanical sieve is performed and for soil that

pass No. 200 hydrometer test is performed.

The following series of sieve, of square- mesh woven wire cloth, was used for sieve

analysis based on the maximum particle size but additional sieves (3”, 2”, 1.5” and 1”)

were used to draw the grain size distribution curve to get uniform spacing and to well

present the test data.

3/4" (75mm) No. 16 (1.18mm)

1/2” (12.5mm) No. 30 (600 µm)

3/8” (9.5mm) No. 40 (425 µm) No.4 (4.75mm) No. 50 (300 µm) No.8 (2.36mm) No. 100 (150 µm) No. 10 (2 mm) No. 200 (75 µm)

In the sedimentation test 50 grams of soil was taken and soaked for 24 hours by adding

125 ml of dispersing agent (sodium hexametaphosphate (40 g/L)) solution the soaked

sample then further dispersed using a stirring apparatus. Then it poured into 1000ml

cylinder and starred further for a period of 1min by covering it with robber stopper. Then

the actual hydrometer reading and test temperature was taken for 0.1, 0.5, 1, 2, 4, 8, 15,

30, 60, 120, 240, 480, 1440, minutes.

The summary of grain size analysis result is shown in Table 4.4 and the combined grain

size distribution cure is shown in Figure 4.2 from grain size analysis result clay content

ranging from 10.03 – 32.32%, silt fraction from 36.82 – 80.65%, sand fraction 5.77 -

92.17% and gravel content from 0.0 – 18.77%. Grain size analysis curve for each test pits

is shown in Appendix c.

26

Table 4. 4 summary of grain size analysis results

Serial No

Designation Depth(m)

Percent amount of particle size corrected

Gravel (%) Sand (%) Silt (%) Clay (%)

1 TP-1-1.4 0.20-1.4 0.68 14.76 60.48 24.08

2 TP-1-3.0 1.4-3.0 9.35 15.63 51.07 23.95

3 TP-3-1.5 0-1.5 0.46 19.12 69.15 11.27

4 TP-3-3.0 1.5-3.0 4.98 95.03 0.00 0.00

5 TP-4-1.55 0.4-1.55 0.09 9.23 80.65 10.03

6 TP-4-3.0 1.55-3.0 2.15 9.73 65.33 22.7

7 TP-5-1.1 0.0-1.1 5.24 12.91 62.12 19.73

8 TP-5-1.8 1.1-1.8 3.72 13.69 54.97 27.62

9 TP-5-3.0 1.8-3.0 0.00 11.17 58.77 30.06

10 TP-6-1.5 0.0-1.5 0.00 21.02 67.26 11.72

11 TP-6-3.0 1.5-3.0 18.77 31.67 36.83 12.73

12 TP-7-1.2 0.0-1.2 0.00 5.77 70.62 23.61

13 TP-7-3.0 1.2-3.0 0.00 6.11 66.26 27.63

14 TP-8-1.5 0.00-1.50 0.26 18.70 63.39 17.65

15 TP-8-2.0 1.50-2.00 0.13 14.79 60.42 24.66

16 TP-8-3.0 2.00-3.00 0.07 8.44 73.35 18.14

17 TP-9-1.25 0.00-1.25 1.13 10.32 56.24 32.32

18 TP-9-2.0 1.25-2.00 6.22 13.86 50.27 29.65

19 TP-9-3.0 2.00-3.00 4.04 11.97 56.20 27.79

20 TP-10-1.5 0.00-1.50 0.00 11.86 56.63 31.51

21 TP-10-3.0 2.00-3.00 0.00 13.03 59.17 27.80

27

Figure 4. 2 Combined Grained size analysis curve

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm

Grain Size Distribution Curve

TP 1 1.4 TP 1 3 TP 3 1.5 TP 3 3 TP 4 1.5

TP 4 3 TP 5 1.1 TP 5 1.8 TP 5 3 TP 6 1.5

TP 6 3 TP 7 1.2 TP 7 3 TP 8 1.5 TP 8 2

TP 8 3 TP 9 1.25 TP 9 2 TP 9 3 TP 10 1.5

TP 10 2 TP 10 3

Grain Size Boundary According To ASTM

Gravel Sand Silt Clay Colloids

75 4.75 0.075 0.005 0.001

28

4.2.4 Atterberg limits

4.2.4.1 General

The engineering behavior of fine-grained soils depends on factors other than particle size

distribution. It is influenced primarily by their mineral and structural composition and the

amount of water they contain, which is referred to as water content (or moisture content).

The liquid and plastic limits tests characterize the effects of water content on fined-grained

soils and help to classify fine-grained soils and to assess their mineral composition and

engineering properties [19].

4.2.4.2 Test procedure and Results

The procedure followed to run this test is according to ASTM standard with designation

D-4318

The liquid limit (LL) is arbitrarily defined as the water content, in percent, at which a pat

of soil in a standard cup and cut by a groove of standard dimensions will flow together at

the base of the groove for a distance of 13 mm (1/2 in.) when subjected to 25 shocks from

the cup being dropped 10 mm in a standard liquid limit apparatus operated at a rate of

two shocks per second. The plastic limit (PL) is the water content, in percent, at which a

soil can no longer be deformed by rolling into 3.2 mm (1/8 in.) diameter threads without

crumbling [24].

The summary liquid limit and plastic limit and the calculated plastic index are shown in

Table 4.5. Appendix D shows detail Atterberg limit tests.

29

Table 4. 5 Summary of liquid limit and plastic limit and the calculated plastic index

Sample No Depth LL PL PI

TP-1 1.4 82 39 43

3 76 40 36

TP-3 1.5 63 32 31

3 29 18 11

TP-4 1.55 74 42 32

3 71 40 31

TP-5

1.1 83 39 44

1.8 82 49 33

3 85 50 35

TP-6 1.5 65 34 31

3 66 39 27

TP-7 1.2 77 41 36

3 49 30 18

1.5 49 33 17

TP-8 2 63 48 15

3 65 45 20

1.25 81 47 34

TP-9 2 72 49 27

3 87 48 40

1.5 67 42 24

TP-10 3 64 44 20

30

4.2.5 Free swell

4.2.5.1 General

The free swell test is one of the most common and simplest test method use for identifying

expansive soil in the laboratory. It is defined as the ratio of the changing in volume,

expressed as a percentage [21].

4.2.5.2 Test procedure and Results

This test performed by slowly pouring 10ml of oven dry soil which has passed the No. 40

(0.425mm) sieve into 100ml graduated cylinder filled with water after 24 hours, final

volume of the suspension being read.

Summary of free swell results are shown in Table 4.6. From these results one can see

that the free swell of soil under investigation ranges from 20% to 60%.

31

Table 4. 6 Free Swell result of the study area

Serial No

Designation Depth(m) Test Conditions

Free Swell (%) PI Remark

1 TP-1-1.4 0.20-1.4 Oven Dry 50 43

2 TP-1-3.0 1.4-3.0 Oven Dry 45 36

3 TP-3-1.5 0-1.5 Oven Dry 35 31

4 TP-3-3.0 1.5-3.0 Oven Dry 25 11

5 TP-4-1.55 0.4-1.55 Oven Dry 60 32

6 TP-4-3.0 1.55-3.0 Oven Dry 50 31

7 TP-5-1.1 0.0-1.1 Oven Dry 60 44

8 TP-5-1.8 1.1-1.8 Oven Dry 55 33

9 TP-5-3.0 1.8-3.0 Oven Dry 45 35

10 TP-6-1.5 0.0-1.5 Oven Dry 40 31

11 TP-6-3.0 1.5-3.0 Oven Dry 35 27

12 TP-7-1.2 0.0-1.2 Oven Dry 20 36

13 TP-7-3.0 1.2-3.0 Oven Dry 50 18

14 TP-8-1.5 0.0-1.5 Oven Dry 30 17

15 TP-8-2.0 1.5-2.0 Oven Dry 40 15

16 TP-8-3.0 2.0-3.0 Oven Dry 20 20

17 TP-9-1.25 0.0-1.25 Oven Dry 50 34

18 TP-9-2.0 1.25-2.0 Oven Dry 40 27

19 TP-9-3.0 2.0-3.0 Oven Dry 40 40

20 TP-10-1.5 0.0-1.5 Oven Dry 50 24

21 TP-10-3.0 1.5-3.0 Oven Dry 40 20

32

4.3 Classification of soils

4.3.1 General

Soils, in general, may be classified as cohesionless and cohesive or as coarse-grained

and fine-grained. These terms, however, are too general and include wide range of

engineering properties. Hence, additional means of categorization are necessary to make

the terms more meaningful in engineering practice. These terms are compiled to form soil

classification system [14].

A soil classification system represents, in effect, a language of communication between

engineers. It provides a systematic method of categorizing soil according to their probable

engineering behavior, and allows engineers access to the accumulated experience of

other engineers. A classification system does not eliminate the need for detailed soils

investigations or for testing for engineering properties. However, the engineering

properties have been found to correlate quite well with the index and classification, the

engineer already has a fairly good general idea of the way the soil will behave in the

engineering situation, during construction and under structural loads [18].

4.3.2 Classification based on Unified soil classification (USC) system

The USCS is formalized in ASTM D2487 Standard Practice for Classification of Soils for

Engineering Purposes (Unified Soil Classification System). The practice is simple,

relevant to all soil types, incorporated widely in practice, and relatively fast to use. In

addition to a soil description, a USCS classification requires quantitative grain size and

Atterberg Limits data, except limits are not required if the material contains less than 5

percent fines. The system is based on two simple principles: size distribution of the grains

is important for coarse - grained material, and the interaction of the grains with water is

most important for fi ne - grained material. Materials are then separated into fractions

based on mass percentages. One obvious shortcoming of the USCS is the fact that it

ignores the importance of particle geometry for coarse - grained materials [22].

33

According to USCS most of the soil of the research area falls in MH region. From the plot

of plasticity chart in Figure 4.3 and the classification soils in Table 4.7 the soil found in

Mojo Town are Silt, Silt with Sand, Sand and Sandy Silt with Gravel.

34

Table 4. 7 Classification of soil based on Unified Soil Classification System (USCS)

Designation Depth (m)

Percent amount of particle size LL (%)

PI (%)

Classification according to USCS

Group name ASTM D-2487

Gravel Sand Silt Clay

TP-1-1.4 0.20-1.4 0.68 14.76 60.48 24.08 82 43 MH elastic silt with sand


TP-3-1.5 0-1.5 0.46 19.12 69.15 11.27 63 31 MH elastic silt with sand

TP-3-3.0 1.5-3.0 4.98 95.02 0.00 0.00 29 11 SP poorly graded sand

TP-4-1.55 0.4-1.55 0.09 9.23 80.65 10.03 74 32 MH elastic silt






TP-6-3.0 1.5-3.0 18.77 31.63 36.83 12.73 66 27 MH sandy elastic silt with gravel


TP-7-3.0 1.2-3.0 0.00 6.11 66.26 27.63 49 18 ML silt

TP-8-1.5 0.0-1.5 0.26 18.70 63.39 17.65 49 17 ML silt with sand








35

Figure 4. 3 Plasticity chart of the study area according to USCS

Tp-1-1.4

TP-1-3

TP-3-1.5 TP-4-1.55

TP-4-3

TP-5-1.1

TP-5-1.8TP-5-3

TP-6-1.5

TP-7-1.2

TP-6-3

TP-7-3

TP-8 1.5TP 8-2, 15

TP 8-3

TP 9-1.25

TP 9-2

TP 9-3

TP 10-3

0

10

20

30

40

50

60

0 10 20 30 40 50 60 70 80 90 100 110

PLA

STIC

ITY

IN

DEX

(%

)

LIQUID LIMIT (%)

Plasticity ChartA-Line

U-Line

Boundary

Series4

Series5

Series6

Tp-1-1.4

TP-1-3

TP-3-1.5

TP-4-1.55

TP-4-3

TP-5-1.1

TP-5-1.8

TP-5-3TP-6-1.5

TP-7-1.2TP-6-3

TP-7-3

TP-8 1.5TP 8-2

TP 8-3

TP 9-1.25

TP 9-2

TP 9-3

TP 10-1.5

TP 10-2

TP 10-3

CL OR MLML OR OL

36

4.4 Geotechnical map of Mojo town

The Geotechnical Map of Mojo Town is prepared to give the general over view of soil and

rock distribution. Figure 4.4.

The mapping is prepared based on filed visits laboratory investigation of soil samples,

and based on previous studies which is done by Oromia urban planning institute, 2009

with the supplement from field observation and finally GPS delineation is made.

37

Figure 4. 4 Geotechnical Map of Mojo Town

38

4.5 Compaction

4.5.1 General

There are many situations in engineering practice when the soil itself is used as a

construction material. In the construction of engineering structures such as highway

embankments or earth dams, Loose fills need to be compacted to increase their density

and improve its strength characteristics. Sometimes, an existing soil deposits may need

to be ‘improved’ in order to enhance its engineering performance.

Compaction generally leads to an increase in shear strength and helps improve the

stability and the bearing capacity of a soil. It also reduces the compressibility and

permeability of the soil. Detrimental settlement can be prevented and undesirable volume

changes through swelling and shrinkage can be controlled [14].

4.5.2 Test procedure and Results

There are several laboratory methods for determining the compaction characteristics. The

two most commonly used methods are the standard and the modified dynamic hammer

tests. These methods are standardized as ASTM D698 Laboratory Compaction

Characteristics of Soil Using Standard Effort and D1557 Laboratory Compaction

Characteristics of Soil Using Modified Effort. In this research work the procedure followed

ASTM D698.

From the test results the maximum dry density of the soil under investigation ranges from

1.18 to 1.83 g/cm3 and the optimum moisture content ranges 14.57 to 44.33 percent. The

summary of the result is shown in Table 4.8 and Figure 4.5 and detail compaction curve

for each sample is shown in Appendix E.

39

Table 4. 8 Summary of optimum moisture content and maximum dry density.

s.no Designation Depth MDD (g/cm3) OMC (%)

1 TP 1-1.4 0.20-1.4 1.28 31.65

2 TP 1-3.0 1.4-3.0 1.27 31.86

3 TP 3-1.5 0-1.5 1.36 33.22

4 TP 3-3.0 1.5-3.0 1.83 14.57

5 TP 4-1.5 0.4-1.55 1.46 24.77

6 TP 4-1.1 1.55-3.0 1.19 39.63

7 TP 5-1.1 0.0-1.1 1.46 24.78

8 TP 5-1.8 1.1-1.8 1.27 37.04

9 TP 5-3.0 1.8-3.0 1.18 44.33

10 TP 6-1.5 0.0-1.5 1.23 39.01

11 TP 6-3.0 1.5-3.0 1.26 40.08

12 TP 7-1.2 0.0-1.2 1.46 24.78

13 TP 7-3.0 1.2-3.0 1.33 33.1

14 TP-8-1.5 0.0-1.5 1.28 33.1

15 TP-8-2.0 1.5-2.0 1.15 38.8

16 TP-8-3.0 2.0-3.0 1.19 41.0

17 TP-9-1.25 0.0-1.25 1.22 36.3

18 TP-9-2.0 1.25-2.0 1.24 38.2

19 TP-9-3.0 2.0-3.0 1.22 43.3

20 TP-10-1.5 0.0-1.5 1.21 37.3

21 TP-10-3.0 1.5-3.0 1.23 35.6

40

Figure 4. 5 Summary of compaction curve

1.00

1.10

1.20

1.30

1.40

1.50

1.60

1.70

1.80

1.90

0 5 10 15 20 25 30 35 40 45 50 55 60

DR

Y D

EN

SIT

Y (G

/C

M3)

MOISTURE CONTENT(%)

SUMMERY OF COMPACTION

TP 1-1.4

TP 1-3.0

TP-3-1.5

TP-3-3

TP-4-1.5

TP-4-3

TP-5-1.1

TP-5.1.8

TP-5-3

TP-6-1.5

TP-6-3.0

TP-7-1.2

TP-7.3

TP-8-2

TP-8-3

TP-9-1.25

TP-9-2

TP-9-3

TP-10-1.5

TP-10-3

41

4.6 Direct Shear

4.6.1 General

An understanding of the shear strength of soil is essential in foundation engineering. This

is because most geotechnical failures involve a shear type failure of the soil. This is due

to the nature of soil, which is composed of individual soil particles that slide (i.e., shear

past each other) when the soil is loaded. The shear strength of soil is required for many

different types of engineering analyses, such as the bearing capacity of shallow and deep

foundations, slope stability analyses, and the design of retaining walls etc.

A popular apparatus to determine the shear strength parameters for silt and granular

materials is the shear box which the soil mass is likely to fail along a thin zone under

plane strain conditions [30].


The procedure followed to run this test is according to ASTM D3080: Standard Test

Method for Direct Shear Test of Soils under Consolidated Drained Conditions

In direct shear test there are two main procedures in the application of shear force VIZ:

a) strain controlled (strain is increased at constant rate) and stress controlled (Stress

increased at a constant rate) [2]. In this research work the strain is fixed and the stress is

increased at different intervals. Table 4.9 shows summary of shear stress parameters and

detailed shear stress descriptions for each test pits are shown in Appendix F.

Table 4. 9 summary of shear stress parameters

TP Location Depth (m) In-situ moisture content

Dry Density (gm/cc)

C (kPa) Ø (degree)

TP-3 3.0 5.29 1.61 1 29

TP-8 3.0 28.85 1.17 26 19

TP-9 3.0 29.94 1.14 22 18

TP-10 3.0 17.27 1.18 24 12

42

4.7 Unconfined Compression

4.7.1 General

Unconfined compressive strength testing provides a quick and simple means to measure

the unconfined compressive strength (qu) and undrained shear strength (su) of normally

consolidated and slightly over consolidated cylindrical specimens of cohesive soil. This

information is used to estimate the bearing capacity of spread footings and other

structures.


The procedure followed to run this test is according to ASTM D2166: Standard Test

Method for Unconfined Compressive Strength of Cohesive Soil.

The strength of the soil determined by compressive tests varies with height to diameter

ratio of the spacemen and rate of strain. The height to diameter ratio of the spacemen

should be in between 2 to 2.5 and the soil spacemen is typically sheared in a controlled

strain apparatus at a strain rate of 0.5 to 2 percent axial strain per minute [35].

For this research work the test is done by 1.7mm/min. However, ASTM D2166-00 (2004)

recommends that the strain rate be chosen so that the time of failure doesn’t exceed

15min. soft cohesive soils will need a larger deformation to reach failure and should be

tested at higher strain rate. Stiff cohesive soils will need less deformation to reach failure

and should be tested at lower rate of strain.

The unconfined compression strength test conducted for selected undisturbed samples of

Mojo cohesive soil show that the soil has Stiff state of consistency Table 4.10 Shows

Unconfined Compression Test Results of Undisturbed soil sample of the research area and

their graphical presentation are shown in Appendix G.

43

Table 4. 10 Unconfined Compression Test Results of Undisturbed Soil sample Mojo Town

Test Pit Depth (m)

Unconfined compressive Strength(qu), kPa

Undrained Shear Strength(cu), kPa

Moisture content (%)

Consistency [5]

1 1.40 161 81 23.1 Stiff

3.00 176 88 21.5 Stiff

4 1.55 139 69 31.5 Stiff

3.00 135 68 30 Stiff

5

1.10 156 78 26.9 Stiff

1.80 169 85 23.6 Stiff

3.00 137 69 30 Stiff

6 1.50 179 90 20.4 Stiff

3.00 173 87 24.6 Stiff

7 1.20 164 82 23.5 Stiff

3.00 166 83 22.1 Stiff

4.8 Consolidation

4.8.1 General

When a soil deposit is loaded, for example by a structure or man-made fill, deformation

will occur. The total vertical deformation at the surface resulting from the load is called

settlement.

The compressibility characteristics of a soil deposit might be due to

1. Deformation of soil grains,

2. Compression of air and water in the voids, and/or

3. Squeezing out of water and air from the voids.

For typical loads that are encountered in practices, the amount of compression of soil

grains is small and usually neglected. When, compressible soils are found below the

water table, and they can be considered fully saturated. The compression of the pore fluid

is also neglected. Therefore most of volume change is from the soil deposits. As the pore

fluid is squeezed out, the soil grains rearrange themselves into a more stable and denser

configuration, and a decrease in volume and surface settlement results. How fast this

process occurs depends on the permeability of the soil. How much rearrangement and

compression takes place depends on the rigidity of the soil skeleton, which is a function

of the soil structure [20].

44

Generally the consolidation of a soil deposit can be divided into three stages: initial

consolidation, primary and secondary consolidation [3].

4.8.2 Test Procedure and Results

This test was done according to ASTM standard test procedure Designation D2435-96

The undisturbed sample which is brought from the site was extrude using sample extruder

onto the consolidation ring and trim the protrude soil above the ring. Then a 7kPa setting

load is applied till the soil is fully saturated. Then load is applied in twofold increment

every 24hr starting from 25kPa to 1600kPa and the compression dial reading is taken at

a time interval of 0.1, 0.25, 0.5, 1,2,4,8,15,30 minutes and 1, 2, 4, 8, and 24 hours. And

then unloading of the sample was done in similar manner. The plot of void ratio versus

logarithm of pressure and pressure is shown in Figure 4.6 and Figure 4.7 respectively.

Figure 4. 6 Effective vertical stress vs. void ratio on semi log scale

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1 10 100 1000 10000

Vo

id ratio

, e

Pressure (log scale)

Void ratio Vs log Pressure curve

TP 5@3m (MH)

TP 7@3 (ML)

45

Figure 4. 7 Effective vertical stress vs. void ratio on linear scale

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

0 500 1000 1500 2000

Vo

id ratio

, e

Pressure

Void ratio Vs log Pressure curve

TP 5@3 (MH)

TP [email protected] (ML)

46

4.8.3 Pre Consolidation Pressure

Past history of soil stress and other changes are preserved in the soil structure

(Casagrande, 1932c) [18]. Based on the stress history of saturated cohesive soils, they

are consider to be either under consolidated, normally consolidated or over consolidated.

The over consolidation ratio (OCR) is used to describe the stress history of cohesive soil

and it define as

𝑶𝑪𝑹 =𝑷𝒄

𝑷𝟎 … … … … … … … … … … … … … … … … … … … … … … … … … . (4.1)

Where 𝑃𝑐 is the maximum past pressure which is also known as the pre consolidation

pressure which is equal to the highest previous vertical effective stress that the cohesive

soil was subjected to and completely consolidated this value often estimated from the

Casagrande construction technique. And 𝑃𝑜 refers existing vertical effective stress [35].

The Casagrande (1936) technique involves locating the point of maximum curvature B,

on the laboratory e-log p curve of an undisturbed sample as shown in Figure 4.8. From

B, a tangent is drawn to the curve and a horizontal line is also constructed. The angle

between these two lines is then bisected. The abscissa of the point of intersection of this

bisector with the upward extension of the inclined straight part corresponds to the pre

consolidation pressure, 𝑃𝑐 [31]. Typical void ratio vs. pressure curve is shown in Figure

4.9.

Figure 4. 8 Method of determining Pc by Casagrande method

47

Figure 4. 9 Typical void ratio vs. pressure curve to determine 𝑷𝑪

4.8.4 Coefficient of consolidation (𝑪𝑽)

Coefficient of consolidation (𝐶𝑉) is evaluated from the consolidation test data by the use

of characteristics of the theoretical relationship between the time factor and the degree of

consolidation. These methods are known as ‘fitting methods’, as one tries to fit in the

characteristics of the theoretical curve with the experimental or laboratory curve [6].

The more generally used fitting methods are the following

(a) The square root of time fitting method

(b) The logarithm of time fitting method

4.8.4.1 Square root of time method

The Square Root of Time construction transforms the time scale by plotting strain versus

the square root of time. The method is based on the fact that the first 60 percent of the

theoretical curve is a parabola and will be linear when plotted in this format. A 15 percent

offset line from this initial slope will intersect the theoretical curve at 90 percent

48

consolidation. The method attempts to exploit this feature of the theory by performing a

similar construction on the strain versus square root of time measurements.

The coefficient of consolidation based on the Square Root of Time fitting method is then

calculated using Equation 4.2:

𝑪𝑽 = 𝟎. 𝟖𝟒𝟖 𝑯𝒅

𝒕𝟗𝟎 … … … … … … … … … … … … … … … … … … … … … … … … … . (4.2)

Where:

𝑡 90 = time to 90 percent consolidation for the increment (s)

0.848 = time factor corresponding to 90 percent consolidation (dimensionless) [22]

4.8.4.2 5.7.3.2 Logarithm-of-time-fitting method

This method was devised by A. Casagrande and R.E. Fadum (1939). The point

corresponding to 100 per cent consolidation curve is plotted on a semi-logarithmic scale,

with time factor on a logarithmic scale and degree of consolidation on arithmetic scale,

the intersection of the tangent and asymptote is at the ordinate of 100% consolidation.

Since the early portion of the curve is known to approximate a parabola, the corrected

zero point may be located as follows: The difference in ordinates between two points with

times in the ratio of 4 to 1 is marked off; then a distance equal to this difference may be

stepped off above the upper points to obtain the corrected zero point. This point may be

checked by more trials, with different pairs of points on the curve. After the zero and 100%

primary compression points are located, the point corresponding to 50% consolidation

and its time may easily be obtained and the coefficient of consolidation computed from

Equation 4.3:

𝑪𝑽 = 𝟎. 𝟏𝟗𝟕 𝑯𝒅

𝒕𝟓𝟎 … … … … … … … … … … … … … … … … … … … … … … … … … . (4.3)

Where:

𝑡 50 = time to 50 percent consolidation for the increment (s)

0.197 = time factor corresponding to 50 percent consolidation (dimensionless) [22]

49

The Log Time method is much more rigorous than the Root Time method because it

places more requirements on the shape of the consolidation curve. Therefore, Root

Time method is used in this research work.

4.8.5 Compression Index (𝑪𝑪)

Compression index is used for computing the ultimate settlement of a structure on the

field and it is equal to the slope of the linear portion of void ratio vs. pressure plot [3, 31].

𝑪𝑪 =∆𝒆

𝐥𝐨𝐠(𝑷𝑶+∆𝒑

𝑷𝑶) … … … … … … … … … … … … … … … … … … … … … … … … … . (4.4)

Table 4.11 shows summary of the above consolidation test parameter and their detail

procedures are shown in Appendix G.

50

Table 4. 11 Summary of consolidation test results

Test Pit

Depth (m)

Natural Moisture Content

(%)

Total unit

weight

𝛾 (kPa)

Pressure P

(kPa)

Void ratio

𝑒𝑓

Coefficient of consolidation

𝑐𝑣

(𝑐𝑚2 𝑠𝑒𝑐⁄ )

Compression index

(𝑐𝑐)

Over-burden pressur

e

𝑃0 (kPa)

Pre- Consolidation

Pressure

𝑃𝑐 (kPa)

Over Consolidation Ratio (OCR)

TP-5

3

32

15

7 1.32 -

0.3

45

80

3.8

50 1.24 0.82

100 1.13 0.49

200 1.04 0.64

400 0.95 0.82

800 0.85 0.82

1600 0.77 0.36 TP-7

3

24

14.7

7 1.38 -

0.32

44

140

3.2

50 1.34 0.64

100 1.29 0.25

200 1.23 0.25

400 1.15 0.24

800 1.06 0.24

1600 0.96 0.36

51

4.8.6 Coefficient of Permeability

Permeability is the measure of the soil’s ability to permit water to flow through its pores

or voids. Knowledge of the permeability properties of soil is necessary to: Estimating the

quantity of underground seepage; solving problems involving pumping seepage water

from construction excavation; Stability analyses of earth structures and earth retaining

walls subjected to seepage forces.

Coefficient of permeability can be determined from consolidation test using the following

relationship.

𝒌 =𝒄𝒗∗𝒂𝒗∗𝜸𝒘

𝟏+𝒆 … … … … … … … … … … … … … … … … … … … … … … … … … . (4.5)

Where:

𝑐𝑣: Coefficient of consolidation

𝑎𝑣: Coefficient of compressibility

𝛾𝑤: Unit weight of water

𝑒: Void ratio

Coefficient of compressibility represents the rate of change of void ratio with pressure. It

is numerically equal to the slope of pressure void ratio curve on a natural scale [2].

𝒂𝒗 =∆𝒆

∆𝒑 … … … … … … … … … … … … … … … … … … … … … … … … … . (4.6)

Table 4. 12 Summarizes the calculated value of coefficient of permeability using Eqn. 4.4

52

Table 4. 12 calculated value of coefficient of permeability

Designation

Depth m

Pressure, P

kPa

Void Ratio

𝑒𝑓

Coefficient of consolidation

compressibility, 𝑐𝑣

(𝑐𝑚2 𝑠𝑒𝑐⁄ )

Coefficient of volume

compressibility, 𝑎𝑣

(10−5 𝑐𝑚2 𝑘𝑁⁄ )

Coefficient of

permeability, 𝑘

(10−5 𝑐𝑚 𝑠𝑒𝑐⁄ )

TP-5

3.0

100 1.13 0.49 89.2 20.52

200 1.04 0.64 62.6 19.64

400 0.95 0.82 39.8 16.74

800 0.85 0.82 22.2 9.84

1600 0.77 0.36 12.8 2.60

TP-7

3.0

100 1.29 0.25 215 23.47

200 1.23 0.25 89.6 10.05

400 1.15 0.24 45.3 5.05

800 1.06 0.24 25.5 2.97

1600 0.96 0.36 9.95 1.83

53

5. DISCUSSION AND COMPARISON

5.1 Discussion of laboratory results The laboratory and field test results are discussed in table 5.1

Table 5. 1 Discussion of Laboratory and field test results

Test Result (Min) Result (Max) Remark

In situ density 1.40g/cm3 1.7g/cm3 Field test

Natural moisture content 5.29% 35.85% "

Specific gravity 2.62 2.7

Clay content 18.41% 59.38% Grain size analysis test

Silt fraction 27.9% 72.28% "

Sand fraction 5.77% 92.17% "

Gravel content 0.0% 18.77% "

Liquid limits 29% 87% Atterbreg limit test

Plastic limits 18% 50% "

Plastic index 11% 46% "

Swell potential 20% 60% "

Optimum moisture content (OMC) 1.18 g/cm3 1.83 g/cm3 Compaction test

Maximum Dry Density (MDD) 14.57% 44.33 % "

Angle of internal friction 120 290 Direct shear test

Unconfined Compressive Strength 83kPa 185 kPa

Undrained shear strength 42kPa 92 kPa

Compression index, 0.3 0.32 Consolidation test

Coefficient of consolidation 0.24 𝑐𝑚2 𝑠𝑒𝑐⁄ 0.82 𝑐𝑚2 𝑠𝑒𝑐⁄ "

Coefficient of permeability 1.83 𝑥10−5 𝑐𝑚 𝑠𝑒𝑐⁄ 23.47𝑥10−5 𝑐𝑚 𝑠𝑒𝑐⁄ "

54

5.2 Comparison of results with previous researches

Results of the soil under investigation can be compared with previous researches which

are done on silt soil as shown in table 5.2.

Table 5. 2 Comparison of test results of Mojo Town

Hilina, [16]

Dagnachew, [7]

Current Research

Soil Type Silty Soil Silt and Silt sand Silt, Silt with Sand, Sand and Sandy Silt with Gravel

Location Bishoftu Adama Mojo

Clay Content (%) 4.71 – 30.11 5.37 – 31.62 10.03 – 32.32

Silt Content (%) 6.59 – 68.2 17.62 – 62.1 36.82 – 80.65

Sand Content (%) 7.43 – 59.88 14.48 – 54.6 5.77 - 92.17

LL (%) 69 - 110 29 - 73 29 – 87

PI (%) 46 - 79 5 - 34 18 – 50

In- situ density (g/cm3)

1.12 – 1.47 1.4 – 1.7

Free swell (%) 30.0 – 60.0 18 - 50 20 - 60

Gs 2.53 – 2.70 2.4 - 2.7 2.62 - 2.7

UCS (kPa) 83 – 185

MDD (g/cm3) 1.28 – 1.52 1.20 – 1.62 1.18 – 1.83

OMC (%) 24.5 – 33.3 17.5 – 36.5 14.57 – 44.33

From Plasticity chart

SW,SM,ML and MH

SM, ML, MH SP, ML, MH

55

6. CONCLUSION AND RECOMMENDATION

6.1 Conclusion

The soils in Mojo town are silt, silt with sand, sand and sandy silt with gravel in

which the clay content range from 10.03 to 32.32%, silt fraction from 36.82 to

80.65%, sand fraction 5.77 to 92.17% and gravel content from 0.0 to 18.77%. The

depths of the soil range from few centimeters below ground level to a maximum

depth of three meters. According to Casagrande PI-LL chart most of the samples

fall in Kaolinite and halloysite region. From the values of specific gravity, which

range from 2.62 to 2.70, one can also conclude that the soil is composed of

Kaolinite mineral [25].

The free swell values range from 20 to 60% exhibits low to medium expansion

potential. From the values of Unconfined Compressive strength which ranges from

135 to 179 kPa, the soil is categorized to have stiff consistency in its natural state.

As determined from compaction test the optimum moisture content (OMC) and the

maximum Dry Density (MDD) range from 14.57 to 44.33 % and 1.18 to 1.83 g/cm3

respectively. The higher MDD value is for poorly, graded sand.

The consolidation test results show that the soil under investigation is over

consolidated with an OCR of 3.2 to 3.8. The coefficient of permeability ranges from

1.83 – 23.47𝑥10−5 𝑐𝑚/𝑠𝑒𝑐. According to McCarthy and David F. (1998) the soil is

silt and has poor drainage.

56

6.2 Recommendation

1. In this research limited soil samples are collected, by increasing the sample size

and depth the values of results of this research should be refined.

2. Mojo is found in seismic active area; Dynamic property should be studied before

designing any civil structure.

3. The mineral composition of the soil should be determined from chemical analysis.

4. The geotechnical map of the town is done by using limited amount of test pit. By

increasing the amount of test pits and depth of investigation, the map should be

refined.

5. Field permeability test should be conducted and the results compared with the

laboratory test results.

57

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Group Plc., London, UK.

58

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32. N. Sivakugan, (2001), clay mineralogy lecture note.

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60

APPENDIX – A: Test Pits logs

Test pit: TP-1

Location: High School

Co- N: 948,948.88m

E: 514,325.32m

Sample Date: 25/10/2005

Elevation (m) -1787



Page # 1/9TEST PIT LOG SHEET

Core run(m) Field Description of Soil/rock

Graphic Log

Field test type Sampled for

0.20

1.20

1.60

Fill material

Natural moisture content NMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test, UCS

Field density and Naturalmoisture content

NMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test, Direct shear/ UCS

Stiff black Elasticsilt with sand

Stiff brown Elasticsilt with sand

Test pit: TP-3

Location: No 1 Elementary school

Co- N: 950,387.55m

E: 514,007.82m


Elevation (m) -1795





Graphic Log


1.5

1.50

NMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test, UCS



Stiff Black Elasticsilt with Sand

Loose Poor GradedSand

61

Natural moisture content

Test pit: TP-4

Location: Daema school

Co- N: 949,583.88m

E: 513,683.70m


Elevation (m) -1777





Graphic Log


1.51

1.45

Natural moisture contentNMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test, UCS



Stiff black Elastic silt

Stiff light grayElastic silt

Test pit: TP-5

Location: Beza school

Co- N: 950,384.90m

E: 513,038.78m


Elevation (m) -1774





Graphic Log


1.10

0.70

1.20

Stiff black Elasticsilt with Sand



Stiff dark brownElastic silt withSand

Stiff Brown Elasticsilt

62

0.4 Fill




Test pit: TP-6

Location: TVET

Co- N: 949,911.30m

E: 514,434.46m


Elevation (m) -1788





Graphic Log


1.5

1.55




Stiff blackElastic silt withSand

Stiff gray SandyElastic silt withGravel

Test pit: TP-7

Location: Catholic school

Co- N: 949,640.29m E: 513,459.55m


Elevation (m) -1779





Graphic Log


1.20

1.80




Stiff black Elastic Silt

Stiff whitish gray silt

63

Test pit: TP-8

Location: Dry Port

Co- N: 950,125.38m

E: 514,308.47m


Elevation (m) -1802





Graphic Log


1.5

1.0



NMC, Gs, Grain size analysis, Consistencylimit test, Compaction test Free swell test,

Brown Silt withSand

Brown Ealstic Silt withSand

Test pit: TP-9

Location: Tekle Haymanot Church

Co- N: 949,640.29m E: 513,459.55m


Elevation (m) -1791





Graphic Log


1.25

1.0



NMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test

Black Elastic Silt

64



Brown Elastic Siltwith sand

0.5

0.75

Gray Elastic silt withSand

Gray Elastic siltwith Sand

Natural moisture content

NMC, Gs, Grain size analysis,Consistency limit test, Compaction testFree swell test, Direct shear

Test pit: TP-10

Location: Chaina Cemnt Factory

Co- N: 945,179.46m

E: 511,206.30m


Elevation (m) -1759





Graphic Log


1.5

1.55




Black Elastic Silt

Brown Elastic Silt

Test pit:

Location:

Co- N: E:

Sample Date:

Elevation (m) -



Page #TEST PIT LOG SHEET


Graphic Log


1.50

1.50




65

66

APPENDIX – B: Meteorological data

67

Table B.1 Summary of monthly maximum temperature in 0c

Region: East Showa Latitude 080 35’ Altitude 1730 -1890mt

Woreda: Lome Longitude 390 07’ Station: Mojo

Year Jan Feb March April May June July Aug Sept Nov Oct Dec

1983 24.2 27.6 29.1 27.2 26.8 28.5 26.7 25.4 26.5 27.4 27.2 26.2

1984 27.1 28.0 30.8 31.1 29.5 27.0 25.7 26.3 27.5 27.7 28.2 27.7

1985 28.7 28.9 31.4 30.8 30.6 31.5 25.9 24.6 26.6 28.0 28.6 28.9

1986 28.0 30.4 NA 30.0 30.0 26.5 25.3 25.3 26.0 27.6 26.6 26.8

1987 27.2 28.7 28.5 28.5 27.9 27.8 27.0 26.5 28.0 28.9 28.7 28.3

1988 28.1 30.1 31.3 30.9 31.5 28.3 23.8 24.4 25.0 27.4 27.3 27.1

1989 27.0 29.8 30.1 27.5 31.2 28.6 24.2 24.7 25.3 27.6 28.0 27.5

1990 28.2 27.8 28.3 29.2 NA 29.3 25.1 24.5 25.9 27.4 28.0 27.3

1991 29.4 29.0 29.7 30.0 31.3 30.7 24.5 24.3 26.3 28.4 27.6 27.5

1992 28.0 29.2 31.5 31.8 32.2 29.9 24.8 23.5 25.7 27.1 27.2 27.9

1993 27.8 27.5 31.6 29.8 29.3 28.6 26.7 25.9 26.2 28.6 28.7 28.5

1994 29.5 30.8 32.0 31.8 32.9 28.4 24.8 23.9 25.2 27.2 26.5 26.2

1995 27.9 29.2 29.0 29.2 30.7 30.0 24.5 24.8 26.0 27.9 28.2 28.2

1996 NA 29.0 29.0 29.9 29.9 29.3 26.6 24.9 26.9 27.5 27.5 27.2

1997 28.0 28.5 30.9 29.2 30.7 28.6 25.2 26.3 28.1 28.5 27.5 28.2

1998 29.2 30.4 31.1 32.0 31.9 32.3 26.9 24.5 25.7 27.0 26.7 27.0

1999 NA 30.8 30.5 31.0 30.8 30.1 29.4 29.3 28.8 28.6 29.3 NA

2000 28.5 29.7 30.9 30.6 30.6 29.1 24.3 24.3 26.4 27.5 28.4 28.2

2001 28.1 29.6 29.5 30.9 30.1 28.3 26.3 26.0 27.8 29.7 29.5 29.6

2002 29.2 30.0 29.4 29.9 30.5 29.4 28.1 27.5 28.8 28.4 29.3 27.7

2003 28.6 30.4 29.9 29.6 32.1 30.0 25.5 26.8 29.4 30.3 28.9 27.6

2004 29.0 29.4 30.2 31.1 32.9 NA 27.4 29.1 30.3 29.4 30.5 NA

2005 NA NA 31.7 32.5 31.7 31.6 27.3 28.1 28.1 30.1 28.4 28.1

2006 30.2 31.7 30.9 30.2 32.9 30.7 27.9 27.0 29.5 31.2 30.3 30.1

2007 30.2 33.7 33.8 32.8 34.1 32.1 27.5 28.2 31.0 30.6 30.3 29.9

2008 29.2 28.5 31.5 30.5 30.6 28.1 24.8 24.6 26.3 27.8 26.1 27.4

2009 27.6 29.5 31.1 31.0 31.8 32.1 25.8 24.8 27.6 27.4 28.5 27.8

2010 28.6 29.3 29.1 30.0 29.0 29.8 25.6 25.6 26.6 29.0 28.9 28.3

2011 30.5 30.6 30.4 30.5 31.6 30.8 29.9 26.1 25.5 28.0 28.4 27.8

68

Table B.2 Summary of monthly minimum temperature in 0c




1983 NA NA NA NA NA NA 12.3 14.1 13.7 11.3 9.8 9.9

1984 8.0 9.1 13.8 15.7 16.1 16.0 14.4 15.1 14.0 11.2 11.3 8.7

1985 8.5 11.0 13.0 13.5 13.5 12.7 12.6 12.7 12.0 9.6 9.3 7.9

1986 6.3 13.6 13.8 14.0 14.4 14.7 13.3 8.7 7.7 6.3 3.8 10.3

1987 11.4 11.3 15.3 13.9 14.5 15.0 15.1 14.7 14.6 13.1 10.3 9.8

1988 11.5 13.8 14.8 15.3 15.3 14.2 15.2 14.7 14.2 11.5 7.0 9.9

1989 8.6 12.2 10.0 NA NA NA NA NA NA NA 9.3 11.9

1990 10.4 14.1 13.1 13.3 13.1 12.9 13.9 14.1 13.2 10.4 9.6 7.5

1991 11.0 13.6 14.5 14.3 14.2 14.0 14.4 13.9 13.1 11.8 8.7 10.1

1992 11.5 12.6 14.7 14.3 13.6 13.1 13.5 13.9 11.9 10.4 10.6 11.3

1993 10.9 11.5 11.3 13.8 13.9 13.5 13.9 13.9 13.2 12.2 9.5 8.6

1994 8.5 10.3 13.7 14.5 13.8 13.0 15.2 14.7 14.0 10.8 9.7 9.3

1995 8.4 12.6 14.2 15.2 14.8 14.0 14.5 14.8 14.0 13.6 10.4 11.4

1996 11.0 11.0 13.3 13.3 13.5 13.2 15.0 14.4 13.0 10.2 9.6 8.0

1997 11.5 9.7 14.6 13.3 13.4 15.1 14.6 14.6 12.5 11.7 13.3 9.0

1998 11.5 11.1 12.6 13.8 13.1 13.0 14.0 15.3 14.5 13.0 8.4 6.8

1999 NA 11.9 14.2 13.1 12.5 12.7 13.0 12.7 12.9 12.7 13.3 NA

2000 NA NA NA NA NA NA NA NA NA NA NA NA

2001 7.7 10.3 12.6 13.1 14.0 13.6 13.5 14.0 12.4 10.7 10.4 7.0

2002 9.0 8.7 12.3 12.6 12.4 12.9 14.0 14.5 12.3 10.6 9.2 9.4

2003 9.7 11.1 10.8 12.7 13.4 12.4 8.7 8.5 9.9 8.0 9.6 6.1

2004 9.0 9.4 10.2 11.2 12.9 NA 6.9 7.6 9.2 8.6 6.9 NA

2005 NA NA 11.1 12.0 10.8 9.8 7.1 6.5 6.8 7.1 6.8 4.8

2006 8.1 11.1 10.0 9.9 12.3 9.2 7.4 6.8 9.4 11.2 8.5 8.1

2007 8.9 12.2 13.2 12.7 13.0 11.7 8.1 9.3 10.8 8.1 8.5 8.5

2008 9.8 10.1 11.7 14.2 14.6 14.0 13.8 13.7 13.5 12.3 9.4 6.5

2009 9.6 11.2 13.7 14.2 14.0 13.9 14.5 14.1 13.2 11.1 8.7 12.6

2010 9.0 13.3 13.5 14.2 14.6 14.4 14.5 14.8 13.6 11.4 10.0 7.5

2011 11.2 17.6 12.1 13.7 14.9 14.4 14.3 14.3 13.1 9.9 10.6 6.8

69

Table B.3 Summary of monthly Rainfall data (mm)




1982 12.9 46.4 13.5 9.0 21.9 4.0 46.1 91.0 13.3 13.9 9.3 0.0

1983 1.3 11.1 24.2 31.7 52.0 32.1 61.9 81.7 33.5 6.1 0.0 0.0

1984 0.0 0.0 4.6 0.0 26.1 21.5 80.2 72.9 38.3 0.0 0.0 2.3

1985 0.0 0.0 1.9 20.8 26.8 3.3 98.1 92.6 42.7 0.6 0.0 0.0

1986 0.0 20.1 11.0 19.7 10.5 60.9 21.3 21.0 24.2 1.0 0.0 0.0

1987 0.0 8.1 31.2 25.2 66.2 3.0 49.8 75.4 17.8 4.7 0.0 0.0

1988 6.6 2.2 2.2 9.9 3.5 41.6 82.5 97.0 81.1 20.3 0.0 0.0

1989 0.0 5.3 40.4 28.3 0.0 25.7 56.6 134.0 38.8 7.3 0.0 0.6

1990 0.0 46.8 15.5 18.2 2.3 6.9 94.1 73.8 41.8 0.1 0.0 0.0

1991 0.0 11.1 47.5 1.4 4.5 18.4 106.4 66.1 30.7 0.0 0.0 0.0

1992 13.3 1.9 3.2 16.2 4.5 28.7 59.0 92.6 27.6 8.8 3.6 0.6

1993 0.6 7.0 0.0 27.8 23.5 20.6 92.4 69.9 27.4 1.7 0.0 0.0

1994 0.0 0.0 7.3 13.2 16.8 29.1 81.0 37.9 42.4 0.0 13.4 0.8

1995 0.0 16.3 11.9 24.5 10.1 10.9 59.9 46.4 35.5 0.9 0.0 0.0

1996 49.0 8.1 31.5 24.1 41.0 71.6 71.4 71.3 26.5 0.0 1.0 0.0

1997 9.8 0.0 12.1 5.6 5.2 43.5 69.7 51.2 25.9 17.8 7.0 0.0

1998 10.4 2.7 17.5 15.3 14.8 37.4 52.0 88.6 49.7 49.7 0.0 0.0

1999 10.1 0.0 5.9 0.0 1.4 30.3 174.7 120.7 22.5 28.2 0.0 0.0

2000 0.0 0.0 3.9 3.4 10.7 42.7 92.2 74.5 38.0 4.1 8.5 0.0

2001 0.0 10.2 25.6 7.5 35.8 43.8 59.6 56.6 18.3 0.0 0.0 0.0

2002 0.0 0.0 2.9 4.6 2.1 20.8 62.4 54.6 31.7 0.0 0.0 4.8

2003 13.1 20.0 24.2 28.1 7.5 43.0 126.8 47.9 32.0 0.0 0.0 4.6

2004 5.0 0.0 32.0 38.2 3.2 54.9 127.0 64.9 39.0 32.0 10.8 4.5

2005 45.3 7.6 51.8 49.9 63.0 66.8 103.4 99.6 47.8 4.7 3.6 0.0

2006 0.5 13.8 29.2 20.5 6.2 36.0 111.1 86.5 39.2 8.0 0.9 4.1

2007 17.5 8.5 27.0 10.4 35.8 43.2 71.9 73.5 30.6 2.5 0.0 0.0

2008 0.5 0.0 0.0 21.5 24.6 45.7 139.0 130.5 62.9 28.8 16.9 0.0

2009 96.5 112.1 136.9 142.3 139.5 139.4 144.9 141.1 131.5 111.5 87.0 125.6

2010 90.2 132.9 135.5 141.8 146.2 143.6 145.5 147.8 136.1 114.0 99.5 75.0

2011 0.0 0.0 15.3 18.3 39.4 18.2 62.3 56.6 68.2 0.0 105.9 0.0

70

APPENDIX – C: Grain size analysis test results

71

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 1 1.4 TP 1 3



75 4.75 0.075 0.005 0.001

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 3 1.5 TP 3 3



75 4.75 0.075 0.005 0.001

72

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 4 1.5 TP 4 3



75 4.75 0.075 0.005 0.001

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 5 1.1 TP 5 1.8 TP 5 3



75 4.75 0.075 0.005 0.001

73

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 6 1.5 TP 6 3



75 4.75 0.075 0.005 0.001

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 7 1.2 TP 7 3



75 4.75 0.075 0.005 0.001

74

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 8 1.5 TP 8 2 TP 8 3



75 4.75 0.075 0.005 0.001

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%Grain Size, mm


TP 9 1.25 TP 9 2 TP 9 3


Gravel Sand Silt

Clay

Colloids

75 4.75 0.075 0.005

0.001

75

01

02

03

04

05

06

07

08

09

01

00

0.00010.00100.01000.10001.000010.0000100.0000

Perc

en

tag

e F

iner,

%

Grain Size, mm


TP 10 1.5 TP 10 3



75 4.75 0.075 0.005 0.001

76

APPENDIX – D: Atterberg limits test results

77

Sample No : TP-1

Sample Depth, m : 1.5

Liquid Limit Plastic Limit

Trial No 1 2 3 4 1 2

Container No IT6 A3 C15 F4 Abr G1

Mass of container, g 21.80 22.20 22.00 22.00 22.10 22.00

Mass of container + Wet soil, g 27.30 28.70 28.20 27.40 28.10 28.40

Mass of container + Dry soil, g 24.90 25.80 25.40 24.90 26.40 26.60

Mass of water, g 2.40 2.90 2.80 2.50 1.70 1.80

Mass of dry soil, g 3.10 3.60 3.40 2.90 4.30 4.60

Water content, % 77.42 80.56 82.35 86.21 39.53 39.13

No of blows 35 29 22 20 ------ ------

Liquid Limit, % = 82 Plastic Limit, % = 39 PI, %= 43

Tested by

Verified by

y = -13.66ln(x) + 126.08

R² = 0.91

55

65

75

85

95

10 100

Water C

ontent, %

No of blows

Flow Curve

78

Sample No : TP-1

Sample Depth, m : 3


Trial No 1 2 3 4 1 2

Container No G1 C31 A36 C18 C34 71

Mass of container, g 21.90 22 21.70 22.00 22.10 22.10



Mass of water, g 2.70 5.10 5.00 4.80 1.80 1.80

Mass of dry soil, g 3.80 6.70 6.50 5.70 4.60 4.50

Water content, % 71.05 76.12 76.92 84.21 39.13 40.00

No of blows 33 26 21 15 ------ ------


Tested by

Verified by

y = -15.85ln(x) + 126.65

R² = 0.96

50

60

70

80

90

100

10 100

Water C

ontent, %

No of blows

Flow Curve

79

Sample No : TP-3



Trial No 1 2 3 4 1 2

Container No T4 T3 B1 W2 H5 G3




Mass of water, g 3.20 3.00 2.30 2.70 1.50 1.50

Mass of dry soil, g 5.40 4.80 3.60 4.00 4.50 4.80

Water content, % 59.26 62.50 63.89 67.50 33.33 31.25

No of blows 34 29 22 19 ------ ------


Tested by

Verified by

y = -12.47ln(x) + 103.61

R² = 0.92

55

60

65

70

75

80

10 100

Water C

ontent, %

No of blows

Flow Curve

80

Sample No : TP-3

Sample Depth, m : 3


Trial No 1 2 3 4 1 2 3

Container No C15 IT-6 G1 Abr C4 96 94

Mass of container, g 21.90 21.70 22.00 22.10 21.90 22.00 22.10

Mass of container + Wet soil, g 30.20 32.10 31.50 37.00 28.10 28.10 28.40

Mass of container + Dry soil, g 28.40 29.80 29.30 33.40 27.10 27.20 27.40

Mass of water, g 1.80 2.30 2.20 3.60 1.00 0.90 1.00

Mass of dry soil, g 6.50 8.10 7.30 11.30 5.20 5.20 5.30

Water content, % 27.69 28.40 30.14 31.86 19.23 17.31 18.87

No of blows 35 27 21 17 ------ ------ ------


Tested by

Verified by

y = -5.84ln(x) + 48.11

R² = 0.96

15

20

25

30

35

40

10 100

Water C

ontent, %

No of blows

Flow Curve

81

Sample No : TP-4



Trial No 1 2 3 4 1 2

Container No abr C4 96 G1 G23 H10




Mass of water, g 2.40 2.60 2.50 3.10 1.80 1.50

Mass of dry soil, g 3.50 3.60 3.20 3.90 4.30 3.50

Water content, % 68.57 72.22 78.13 79.49 41.86 42.86

No of blows 35 29 21 16 ------ ------


Tested by

Verified by

y = -14.37ln(x) + 120.37

R² = 0.95

50

60

70

80

90

100

10 100

Wa

ter

Co

nte

nt,

%

No of blows

Flow Curve

82

Sample No : TP-4

Sample Depth, m : 3


Trial No 1 2 3 4 1 2

Container No 26 A36 H10 19 C34 71




Mass of water, g 2.20 3.70 5.70 4.30 1.70 1.70

Mass of dry soil, g 3.30 5.20 7.90 5.60 4.30 4.30

Water content, % 66.67 71.15 72.15 76.79 39.53 39.53

No of blows 32 27 21 17 ------ ------


Tested by

Verified by

y = -14.34ln(x) + 117.00

R² = 0.92

60

70

80

10 100

Water C

ontent, %

No of blows

Flow Curve

83

Sample No : TP-5



Trial No 1 2 3 4 1 2

Container No B1 R1 F4 G32 G1 R2




Mass of water, g 10.00 7.10 8.20 9.20 1.70 1.70

Mass of dry soil, g 12.90 8.70 9.8 10.40 4.30 4.50

Water content, % 77.52 81.61 83.67 88.46 39.53 37.78

No of blows 40 30 21 17 ------ ------


Tested by

Verified by

y = -11.68ln(x) + 120.68

R² = 0.95

50

60

70

80

90

100

10 100

Water C

ontent, %

No of blows

Flow Curve

84

Sample No : TP-5



Trial No 1 2 3 4 1 2

Container No B28 21 T5 TP5 C34 71




Mass of water, g 7.80 9.20 10.8 10.00 0.28 0.23

Mass of dry soil, g 10.00 11.50 12.80 11.40 0.57 0.47

Water content, % 78.00 80.00 84.37 87.72 49.12 48.94

No of blows 35 28 19 15 ------ ------


Tested by

Verified by

y = -11.45ln(x) + 118.41

R² = 0.99

50

60

70

80

90

100

10 100

Water C

ontent, %

No of blows

Flow Curve

85

Sample No : TP-5

Sample Depth, m : 3


Trial No 1 2 3 4 1 2

Container No C31 C18 A36 26 C34 71




Mass of water, g 8.10 8.70 10.80 10.10 0.28 0.24

Mass of dry soil, g 9.90 10.40 12.20 11.10 0.57 0.47

Water content, % 81.82 83.65 88.52 90.99 49.12 51.06

No of blows 35 29 19 15 ------ ------


Tested by

Verified by

y = -10.97ln(x) + 120.72

R² = 1.00

50

60

70

80

90

100

10 100

Water C

ontent, %

No of blows

Flow Curve

86

Sample No : TP-6



Trial No 1 2 3 4 1 2

Container No H E4 A48 R1 1 F4




Mass of water, g 4.70 3.70 4.00 3.30 1.50 1.60

Mass of dry soil, g 7.40 5.70 6.10 5.00 4.60 4.60

Water content, % 63.51 64.91 65.57 66.00 32.61 34.78

No of blows 34 26 23 19 ------ ------


Tested by

Verified by

y = -4.39ln(x) + 79.12

R² = 0.97

55

60

65

70

75

80

10 100

Water C

ontent, %

No of blows

Flow Curve

87

Sample No : TP-6

Sample Depth, m : 3


Trial No 1 2 3 4 1 2

Container No 26 A36 C31 C18 C34 71




Mass of water, g 3.50 4.80 4.00 3.30 1.70 1.80

Mass of dry soil, g 5.50 7.30 5.90 4.70 4.70 4.30

Water content, % 63.64 65.75 67.80 70.21 36.17 41.86

No of blows 34 27 22 16 ------ ------


Tested by

Verified by

y = -8.78ln(x) + 94.68

R² = 1.00

55

60

65

70

75

80

10 100

Water C

ontent, %

No of blows

Flow Curve

88

Sample No : TP-7


Liquid Limit Plastic

Limit

Trial No 1 2 3 4 1 2

Container No 26 C31 C31 C18 C34 71




Mass of water, g 2.80 5.10 5.10 4.70 1.70 2.10

Mass of dry soil, g 3.80 6.60 6.40 5.80 4.20 5.10

Water content, % 73.68 77.27 79.69 81.03 40.48 41.18

No of blows 33 26 21 15 ------ ------


Tested by

Verified by

y = -9.23ln(x) + 106.77

R² = 0.92

50

60

70

80

90

100

10 100

Water C

ontent, %

No of blows

Flow Curve

89

Sample No : TP-7

Sample Depth, m : 3

Liquid Limit Plastic

Limit

Trial No 1 2 3 4 1 2

Container No C18 C31 26 22 C34 71




Mass of water, g 4.40 3.70 5.00 4.50 1.30 1.60

Mass of dry soil, g 9.50 7.70

9.9 8.80 4.70 4.80

Water content, % 46.32 48.05 50.51 51.14 27.66 33.33

No of blows 33 28 20 17 ------ ------


Tested by

Verified by

y = -7.27ln(x) + 72.02

R² = 0.98

30

40

50

60

10 100

Water C

ontent, %

No of blows

Flow Curve

90

APPENDIX – E: Compaction test results

91

Sample Pit No 1 Sample Depth, m : 1.4 Moisture content Vs dry density comp. table

Existing moisture content, (%) = 8.58

Determination No. 1 2 3 4 5

Mass of Mold, g 4508.6 4508.6 4509.2 4509.7 4510.9

Mass of mold+ Compacted Soil, g 5793.8 5904.9 6102.4 6115.5 6095.5

Mass of Compacted soil, g 1285.2 1396.3 1593.2 1605.8 1584.6

Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.36 1.48 1.69 1.70 1.68

Water Content, % 21.80 25.86 31.65 39.84 47.18

Dry density, g/cm3 1.12 1.18 1.28 1.22 1.14

Max.dry density,(med) = 1.28 Opt. moisture content, %(omc)= 31.6

`

1.10

1.15

1.20

1.25

1.30

1.35

1.40

10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

92

Sample Pit No 1

Sample Depth, m : 3

Moisture content Vs dry density comp. table

Existing moisture content, (%)

= 10.38

Determination No. 1 2 3 4 5 6

Mass of Mold, g 4510.9 4510.9 4510.9 4510.9 4510.9 4510.9

Mass of mold+ Compacted Soil, g 5825.8 5923.8 6089.4 6147.6 6133.7 6132.7

Mass of Compacted soil, g 1314.9 1412.9 1578.5 1636.7 1622.8 1621.8

Volume of Mold,cm3 944 944 944 945 944 944

Bulk density, g/cm3 1.39 1.50 1.67 1.73 1.72 1.72

Water Content, % 21.31 26.04 31.87 37.08 42.37 48.64

Dry density, g/cm3 1.15 1.19 1.27 1.26 1.21 1.16

Max.dry dernsity,(med) = 1.27 Opt. moisture content,

%(omc)= 31.9

`

1.001.051.101.15

1.201.251.301.351.401.451.50

0 5 10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

93

Sample Pit No 3 Sample Depth,

m : 3




Mass of Mold, g 4510.6 4509.8 4509.1 4509.2 4511

Mass of mold+ Compacted Soil, g 6059.7 6167 6234 6490.3 6458.5


Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.64 1.76 1.83 2.10 2.06

Water Content, % 4.50 7.93 9.43 14.57 17.70

Dry density, g/cm3 1.57 1.63 1.67 1.83 1.75

Max.dry dernsity,(med) = 1.83 Opt. moisture content, %(omc)= 14.6

`

1.50

1.55

1.60

1.65

1.70

1.75

1.80

1.85

1.90

0 5 10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

94

Sample Pit No 5 Sample Depth, m : 1.8




Mass of Mold, g 4509 4509.1 4509.1 4510.1 4510.1



Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.41 1.63 1.74 1.72 1.71

Water Content, % 22.11 29.81 37.04 44.50 45.95

Dry density, g/cm3 1.15 1.26 1.27 1.19 1.17


`

1.00

1.05

1.10

1.15

1.20

1.25

1.30

1.35

10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

95

Test Pit No 8 Sample Depth, m : 1.5




Mass of Mold, g 4510 4510 4510 4510 4510



Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.37 1.51 1.71 1.66 1.60

Water Content, % 22.67 26.91 33.06 38.22 41.05

Dry density, g/cm3 1.12 1.19 1.28 1.20 1.14


`

1.001.051.101.15

1.201.251.301.351.401.451.50

10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

96

Sample Pit No 9 Sample Depth, m

: 2




Mass of Mold, g 4510 4510 4510 4510 4510


Mass of Compacted soil, g 1421.6 1542.7 1619.5 1615.

9 1608.3

Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.51 1.63 1.72 1.71 1.70

Water Content, % 29.48 34.02 38.22 42.94 45.28

Dry density, g/cm3 1.16 1.22 1.24 1.20 1.17


`

1.00

1.05

1.10

1.15

1.20

1.25

1.30

25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

97

Sample Pit No 10 Sample Depth, m

: 3




Mass of Mold, g 4510 4508.9 4508.7 4511.

2 4511.1

Mass of mold+ Compacted Soil, g 5750.4 5946.9 6088.5 6064.

4 6043.2

Mass of Compacted soil, g 1240.4 1438 1579.8 1553.

2 1532.1

Volume of Mold,cm3 944 944 944 945 944

Bulk density, g/cm3 1.31 1.52 1.67 1.64 1.62

Water Content, % 23.30 29.79 35.63 43.08 44.52

Dry density, g/cm3 1.07 1.17 1.23 1.15 1.12


`

1.001.051.101.15

1.201.251.301.351.401.451.50

10 15 20 25 30 35 40 45 50

Dry

den

sity

(g/

cm3 )

Moisture content(%)

98

APPENDIX – F: Direct shear test results

99

Sample No. TP 3 Sample Depth, m: 3.00

TP 8 Sample Depth, m: 3.00

.


y = 0.55x + 1.12

R² = 1.00

0

50

100

150

200

0 100 200 300 400

Maxim

um

shear stress

Applied vertical load

Maximum Shear Stress Vs Applied

Vertical Load

0

20

40

60

80

100

120

140

160

0 2 4 6 8 10

Shear stress

Displacement

Shear Stress Vs Displacement

Applied Vertical

Stress 100kPa

Applied Vertical

Stress 200kPa

Applied Vertical

Stress 300kPa

y = 0.35x + 25.65R² = 0.99

0

50

100

150

200

0 100 200 300 400

Maxim

um

shear stress


Maximum Shear Stress Vs Applied Vertical

Load

0

20

40

60

80

100

120

140

160

180

0 2 4 6 8 10

Shear stress

Displacement


Applied Vertical

Stress 100kPa

Applied Vertical

Stress 200kPa

Applied Vertical

Stress 300kPa

100


0

20

40

60

80

100

120

140

0 2 4 6 8 10

Shear stress

Displacement


Applied Vertical

Stress 100kPa

Applied Vertical

Stress 200kPa

Applied Vertical

Stress 300kPa

y = 0.33x + 22.31R² = 1.00

0

50

100

150

200

0 100 200 300 400

Maxim

um

shear stress



Vertical Load

0

20

40

60

80

100

0 2 4 6 8 10

Shear Stress

Displacement


Applied Vertical

Stress 100 kPa

Applied Vertical

Stress 200kPa

Applied Vertical

Stress 300kPa

y = 0.22x + 24.44R² = 0.97

0

50

100

150

200

0 100 200 300 400M

axim

um

shear stress



Vertical Load

101

APPENDIX – G: Unconfined Compression test results

102

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %

Axial Stress Vs Axial Strain

q max =161 kPa

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =176 kPa

103

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =139 kPa

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =135 kPa

104

0

25

50

75

100

125

150

175

0 1 2 3 4 5 6

Axi

al S

tres

s, k

Pa

Axial Strain, %

Axial Stress Vs Axial Strainq max =156 kPaq max =156 kPa

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =169 kPa

TP-5 @ 1.8m

105

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =137 kPa

TP-5 @ 3m

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =179 kPa

TP-6 @ 1.5m

106

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %

Axial Stress Vs Axial Strainq max =173 kPa

TP-6 @ 3.0m

0

25

50

75

100

125

150

175

200

0 1 2 3 4

Axi

al S

tres

s, k

Pa

Axial Strain, %

Axial Stress Vs Axial Strainq max =164 kPa

TP-7 @ 1.2m

107

0

25

50

75

100

125

150

175

200

0 1 2 3 4 5 6 7 8

Axi

al S

tres

s, k

Pa

Axial Strain, %


q max =166 kPa

TP-7 @ 3.0m

108

APPENDIX – H: Consolidation test results

109

Casagrande Graphical Preconsolidation Calculation

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1 10 100 1000 10000

Vo

id ratio

, e


e-log p curve TP-5

𝑷𝑪

0.00

0.20

0.40

0.60

0.80

1.00

1.20

1.40

1.60

1 10 100 1000 10000

Vo

id ratio

, e


e-log p curve TP-7

𝑷𝑪

110

Graphical calculation of coefficient of consolidation for TP-5

2.200

2.300

2.400

2.500

2.600

2.700

2.800

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡

Square root of time 50kpa

2.700

2.900

3.100

3.300

3.500

3.700

3.900

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


111

3.600

3.700

3.800

3.900

4.000

4.100

4.200

4.300

4.400

4.500

4.600

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


4.400

4.500

4.600

4.700

4.800

4.900

5.000

5.100

5.200

5.300

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


112

5.200

5.300

5.400

5.500

5.600

5.700

5.800

5.900

6.000

6.100

6.200

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


6.100

6.200

6.300

6.400

6.500

6.600

6.700

6.800

6.900

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡

Square root of time 1600

113

Graphical calculation of coefficient of consolidation for TP-7

1.700

1.750

1.800

1.850

1.900

1.950

2.000

2.050

2.100

2.150

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


2.090

2.140

2.190

2.240

2.290

2.340

2.390

2.440

2.490

2.540

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡

Square root of time 100 kpa

114

2.390

2.490

2.590

2.690

2.790

2.890

2.990

3.090

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


2.950

3.050

3.150

3.250

3.350

3.450

3.550

3.650

3.750

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


115

3.600

3.700

3.800

3.900

4.000

4.100

4.200

4.300

4.400

4.500

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


4.300

4.500

4.700

4.900

5.100

5.300

5.500

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00

Dia

l Gag

e r

ead

ing

√𝑡


INVESTIGATION INTO SOME OF THE ENGINEERING PROPERTIES OF SOILS FOUND IN MOJO TOWN

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Transcript of INVESTIGATION INTO SOME OF THE ENGINEERING PROPERTIES OF SOILS FOUND IN MOJO TOWN