EFFECT OF SEAWATER ON GEOENVIRONMENTAL

PROPERTIES OF SOILS

A thesis (Phase I) submitted in partial fulfillment of the requirements for

the award of the degree of

M.Tech

in

Environmental Engineering

By

BANTUPALLI SAI VENKATESH

DEPARTMENT OF CIVIL ENGINEERING

NATIONAL INSTITUTE OF TECHNOLOGY

TIRUCHIRAPPALLI – 620 015

DECEMBER 2015

BONAFIDE CERTIFICATE

This is to certify that the project (Phase I) titled EFFECT OF SEAWATER ON

GEOENVIRONMENTAL PROPERTIES OF SOILS is a bonafide record of the work

done by

BANTUPALLI SAI VENKATESH (203414005)

in partial fulfillment of the requirements for the award of the degree of Master of

Technology in Environmental Engineering of the NATIONAL INSTITUTE OF

TECHNOLOGY, TIRUCHIRAPPALLI during the year 2015-2016.

DR. K. MUTHUKKUMARAN Prof. R. JAYASANKAR

Guide Head of the Department

Project Viva-voce held on _____________________________

Internal Examiner External Examiner

i

ABSTRACT

Seawater collected from Bay of Bengal has been used to mix three soil types and its

consistency limits, compaction characteristics and undrained Shear Strength are compared

with the properties of the three soil types mixed with tap water. Results of laboratory

investigation are presented to show that plasticity index decreased from 13 using tap water

to 5 using seawater for the Low compressible clay, from 10 using tap water to 4 using

seawater for the Clayey sand and from 6 using tap to 1 using seawater for the High

compressible clay. The maximum dry unit weight were in the order of 1.96, 1.94, 1.68 g/cc

for the Low compressible clay, Clayey sand and High compressible clay respectively when

mixed with tap water. Using Seawater, the maximum dry unit weight for the clay decreased

from 1.96 g/cc to 1.94 g/cc, but that of clayey sand and High compressible clay increased

from 1.94 g/cc to 2.16 g/cc and from 1.68 g/cc to 1.7 g/cc respectively. In the case of CH

soil, the undrained shear strength increased from 94.45 to 116.94 KPa with the addition of

Seawater. The undrained shear strength of CL, SC soils decreased from 25.13 to 15.7 KPa,

28.75 to 13.92 KPa respectively with the addition of Seawater.

Keywords: Consistency; Compaction; Plasticity Index; Undrained; Shear.

iii

ACKNOWLEDGEMENT

At the very outset, I would like to express my sincere gratitude to my guide

Dr. K. Muthukkumaran, Assistant professor, Department of Civil Engineering for

giving me this opportunity to work under her esteemed guidance. I am greatly indebted to

her for her invaluable advice and support.

I am grateful to Dr. S. T. Ramesh, Associate professor, Department of Civil Engineering

for his valuable support and guidance in making this project a successful one.

I feel it is a great privilege in expressing my thanks to Dr. R. Gandhimathi, Assistant

professor, Department of Civil Engineering for her full-fledged guidance and motivation.

I am extremely grateful to Dr. S. Sundarrajan, Director, National Institute of

Technology, Tiruchirapalli, for having provided me with sufficient facilities to carry out

this work.

I sincerely express my gratitude to my Head of the Department, Dr. R. Jayasankar,

Department of Civil Engineering for providing me the necessary opportunities for the

completion of my project and all others for their guidance and help. I appreciate the

efforts put in by my friends during various stages of my project work. I would also like to

thank the staff members of my department for their invaluable help and guidance.

I would be eternally thankful to my parents for their everlasting care, support and

encouragement.

BANTUPALLI SAI VENKATESH

iii

TABLE OF CONTENTS

Title Page No.

ABSTRACT ................................................................................................................... i

ACKNOWLEDGEMENTS ......................................................................................... ii

TABLE OF CONTENTS ............................................................................................. iii

LIST OF FIGURES ...................................................................................................... iv

LIST OF TABLES v

ABBREVIATIONS ....................................................................................................... v

CHAPTER 1 INTRODUCTION

1.1 General .................................................................................................................. 1

1.2 Causes of seawater intrusion ................................................................................. 1

1.3 Effect of seawater on clay minerals ...................................................................... 2

1.4 Measures to control saltwater intrusion ................................................................ 5

1.5 Motivation of study 6

1.6 Objectives of the Study ......................................................................................... 6

1.7 Organization of the Thesis .................................................................................... 6

1.8 Summary ............................................................................................................... 8

CHAPTER 2 LITERATURE REVIEW

2.1 General .................................................................................................................. 8

2.2 Characterization of four clay minerals .................................................................. 8

2.3 Effect of seawater on atterberg limits ................................................................... 9

2.4 Effect of seawater on swelling characteristics ...................................................... 11

2.5 Effect of seawater compaction characteristics ...................................................... 11

2.7 Summary ............................................................................................................... 20

CHAPTER 3 MATERIALS AND METHODOLOGY

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

3.2 Methodology ......................................................................................................... 13

3.3 Classification of soils ........................................................................................... 14

iv

3.4 Determination of consistency limits ..................................................................... 14

3.4.1 Liquid limit test ..................................................................................................... 14

3.4.2 Plastic limit test ..................................................................................................... 15

3.5 Proctor test ............................................................................................................ 16

3.6 Unconfined compression test ................................................................................ 17

3.7 Summary ............................................................................................................... 18

CHAPTER 4 RESULTS AND DISCUSSIONS

4.1 General .................................................................................................................. 19

4.2 Quality parameters of tap water and seawater ...................................................... 19

4.3 Effect of seawater on the consistency limits ......................................................... 20

4.4 Effect of seawater on the compaction characteristics ........................................... 21

4.5 Effect of seawater on the unconfined shear strength ........................................... 23

4.6 Summary ............................................................................................................... 25

CHAPTER 5 SUMMARY AND CONCLUSIONS

5.1 Summary ............................................................................................................... 26

5.2 Conclusions ........................................................................................................... 26

5.3 Scope of future work ............................................................................................. 27

REFERENCES 28

LIST OF FIGURES

Figure

No. Title Page No.

1.1 Organization of the thesis ................................................................................ 7

3.1 Methodology for Present Study ....................................................................... 13

4.1 Compaction curves for Low Compressible clay using Tap water and

Seawater ........................................................................................................... 21

4.2 Compaction curves for Clayey Sand using Tap water and Seawater .............. 21

v

4.3 Compaction curves for High Compressible clay using Tap water and

Seawater ........................................................................................................... 22

4.4 Stress Strain relation for High Compressible clay using Tap water

and Seawater .................................................................................................... 23

4.5 Stress Strain relation for Low Compressible clay using Tap water

and Seawater .................................................................................................... 23

4.6 Stress Strain relation for Clayey sand using Tap water and Seawater ............. 24

4.7 Variation of Undrained shear strength for different soils with

addition of tap water and seawater ................................................................... 24

LIST OF TABLES

Table No.

. Title Page No.

2.1 Characterization of four Clay Minerals ........................................................... 8

2.2 Atterberg Limit of Clay Minerals .................................................................... 10

3.1 Classification of soils ...................................................................................... 14

4.1 Quality parameters of Tap water and Seawater 19

4.2 Variation of Liquid limit, Plastic Limit on different soils with the

addition of Tap water and Seawater 20

LIST OF ABBREVIATIONS

CL : Low compressible clay

CH : High compressible clay

SC : Clayey sand

Kpa : Kilo pascal

g/cc : gram per cubic centimetre

1

CHAPTER 1

INTRODUCTION

1.1 GENERAL

Seawater intrusion occurs when seawater is drawn into freshwater aquifers. This natural

process is intensified by sea level rise and over pumping of aquifers. Because of the

growing threat of seawater intrusion, there needs to be a closer study to address its

effects on the environment and the stability of soils. The increased occurrence of

seawater intrusion changes the soil chemistry in the environment and may affect the

interaction among soil particles, which could effect important engineering properties

such as soil strength. Because pumping from aquifers creates a cone of depression of

the water table, a cone of ascension of the freshwater-seawater interface is created as

described by the Ghyben-Herzberg ratio, which implies that for every meter drop of the

fresh water table compared to sea level, there is 40 meters of seawater that is drawn into

that column of water, so it could become a significant problem if the percolating water

affects strength. Past studies have shown that percolating water with ionic strength

increases hydraulic conductivity of clayey soils in the laboratory, which could be

explained by the electrical double-layer thickness theory.

1.2 CAUSES OF SEAWATER INTRUSION

When an aquifer is in hydraulic connection with saline / marine water, portions of the

aquifer may contain saltwater while other portions contain fresh water. Freshwater is

slightly less dense (lighter) than saltwater, and as a result tends to float on top of the

seawater when both fluids are present in an aquifer. There is a relationship based on the

density difference between saltwater and freshwater that can be used to estimate the

depth to saltwater based on the thickness of the freshwater zone above sea level. The

relationship is known as the Ghyben-Herzberg relation. The boundary between the

freshwater and the saltwater zones is not sharp but instead is a gradual change over a

finite distance, and is known as the zone of diffusion or the zone of mixing. In

peninsular region of county, all of our groundwater originates as recharge from

precipitation.

This recharge creates a pressure distribution within our aquifers that tends to be highest

in the centre of the islands, lowering as you approach the shorelines. The pressure

2

distribution leads to a flow in the aquifers that is vertically downward near the centre

of the islands, then flowing radially outward toward the shore .Two mixing processes

(diffusion and dispersion) continuously move saltwater into the freshwater zone. Flow

in the freshwater zone sweeps this mixed brackish water toward the shoreline where it

discharges at submarine seeps. The processes of recharge, flow, mixing, and discharge

all work together to hold the interface position in a roughly stationary position. A

change to one or more of these processes can result in a change in the position of the

interface, an inland movement of the interface boundary known as lateral intrusion.

When a well is pumped, water levels in the vicinity of the well are lowered, creating a

drawdown cone.

If a saltwater zone exists in the aquifer beneath the well, the saltwater will rise up

toward the well screen. This rising up of saltwater is known as upconing and is the

second type of seawater intrusion. In reality the groundwater system in peninsular

county is made up of multiple layers of unconsolidated sand and gravel capable of

supplying water to wells (Aquifers). These aquifers are interbedded with lower

permeability layers of silt and clay (Aquitards) that pass water more slowly. Aquifers

and Aquitards in peninsular country vary spatially in both thickness and elevation. In

any given area of the county, there may be several aquifers present, and each aquifer

will have different hydraulic characteristics (recharge, pressure, capacity etc.) and

susceptibility to seawater intrusion. Even within a single aquifer, the hydraulic

characteristics can vary significantly from one location to another.

1.3 EFFECT OF SEAWATER ON CLAY MINERALS

Studies of the distribution of clay minerals in near-shore marine environments (Grim,

Dietz and Bradley, I949 ; Grim and Johns, I954 ; Powers, 1954, 1957) suggest that

diagnosis of such minerals may occur when they are transferred from fresh-water to

sea-water by river action. The mechanism of any changes that take place is not known,

but a first stage must involve reactions of the cations and anions in sea-water with the

minerals through exchange. Theoretical consideration of cation exchange indicates that

a rearrangement of the cations in the exchange positions will take place. Kelley and

Liebig (1934) showed experimentally that a bentonite preferentially adsorbed more

magnesium than sodium from sea-water, Hendricks and Ross (1941) suggested that

adsorption of magnesium ions was important in the genesis of glauconite in marine

sediments. The relations between the cations in seawater and those in the exchange

3

positions probably can be explained by the law of mass action. The process is complex

because of the different bonding energies of Ca2+, Mg2+, K + and Na+ ions ; the effect

of the cations originally in the exchange positions on the clay minerals ; the variation

in charge of the exchange positions ; the ionic activity of the sea-water ; and the buffer

mechanism of seawater.

In view of the importance of the marine environment and of the changes that may take

place in clay minerals after deposition in the sea, a number of observations was made

of the reactions of montmorillonite (Osage, Wyo., A.P.I. standard no. 25b), mixed-layer

mineral (Highbridge, Ky., A.P.I. standard no. 42), " illite " (Fithian, Ill., A.P.I. standard

no. 35), kaolinite (Bath, S.C., A.P.I. standard no. 5), and halloysite (Tintie, Utah, A.P.I.

standard no. 13) when 2% suspensions were allowed to remain in contact with seawater

for varying periods of time.

The relations of clay minerals and various electrolytes together with a knowledge of

the crystal structures and chemical composition of these minerals indicate that the

reactions to be expected between them and seawater will be complex and will be

different for the structurally different clay minerals. Isomorphous replacement of

cations within the clay mineral structures and broken bonds at the edges of the crystals

cause the development of negative charges in excess of the positive charges on the

particles. The different clay minerals vary in the amount of negative charge developed

and hence in their ability to adsorb and exchange cations with those present in a contact

solution. In general, the amount of reaction follows the order of total exchange capacity

of the minerals, which is : kaolinite < halloysite < illite < mixed-layer mineral <

montmorillonite.

The quantity of cations in the exchange positions, and their kind, whether mono or

divalent, influences the reactions with solutions. Soil chemists refer to the condition in

which all the exchange positions are filled with metal cations as " base saturation", a

useful concept when considering exchange reactions. " Base unsaturation " means that

H+ ions take the place of the common metal cations in the exchange positions, and the

" percentage base saturation " indicates the proportion of the exchange positions filled

with metal cations other than H+. The presence of H+ ions in the exchange positions is

complicated by the release of aluminum from the octahedral layer as described by Paver

and Marshall (1934). Recent work by Low (1955), Aldrich and Buchanan (1958), and

Higdon and Marshall (1958) has shown that the aluminum released retards formation

4

of H-clays. The laws governing replacement of cations on a charged clay mineral

Marshall (1954) after extensive experiments to determine the bonding energy of the

common metal cations. In general, this bonding energy is in the order: Ca > Mg > K >

H > Na. However, in certain clay minerals, kaolinite and some Wyoming bentonite, for

example, the bonding energy is Mg > Ca. Divalent ions with strong bonding energy in

contact solutions are able to occupy the exchange positions preferentially to monovalent

ions.

Titration of water suspensions of clay minerals in the H-form with alkaline solutions

gives neutralization curves that indicate that there are several definite exchange sites on

montmorillonite with different capacities for attracting cations. Inflection points occur

on these curves where adsorption of cations takes place. The relation between the

cations in the contact solution and the adsorption of cations by neutralization of

exchange sites on the clay minerals can be explained by the law of mass action

(Schofield and Taylor, 1955; Garrels and Christ, 1956). It has long been known

(Jarusov, 1937) that in systems containing more than one cation, the cation having the

highest mean free bonding energy takes the positions on the clay mineral surface having

the highest bonding energy.

The positions with less bonding energy are therefore left to be filled with cations of

lower bonding energy. Thus Ca2+ and Mg2+ in a mixed electrolyte are bonded rapidly

to the sites of strongest negative charge, leaving monovalent cations, such as: Na+, to

fill sites of weaker negative charges. Another point to be considered about the reaction

of clay minerals with sea-water is that small amounts of SiO2, A12O3, and Fe2O3 are

dissolved from them by sea-water, but it is not known if this solubility is due to a surface

effect as indicated by Nash and Marshall (1956), to the solubility of SiO2 and Al2O3

(the latter is slightly soluble at pH 8.0) at the pH of sea-water (Correns, 1949 ;

Krauskopf, 1956), or to the release of A12O3 from H-clays by a saline solution

(Mukherjee, Chatterjee and Ray, 1948).

Probably the C1- ions in seawater form a complex with the A13+ ions released from the

clay minerals. Seawater is an aqueous solution containing a variety of dissolved solids

and gases. It is a strong electrolyte with pH ranging from 7.5 to 8.4 depending on the

amount of CO2 present. Seawater is a buffer solution because of the presence of

carbonate and borate species. The cation principally affected by buffering action is

5

calcium because of the relation CaCO3 ⇌ CaHCO3 ⇌ H2CO3. This series of reactions

affects the availability of Ca2+ ions to enter into the exchange positions of clay minerals.

Sea-water contains cations in excess of the equivalent anions derived from strong acids

(Harvey, 1957, p. 153). This excess base or titration alkalinity is equivalent, to that of

the bicarbonate, carbonate and borate ions in the water.

1.4 MEASURES TO CONTROL SALTWATER INTRUSION

A number of different measures have been used to control seawater intrusion and to

protect the groundwater resources. The main principle of protection is to increase the

volume of fresh groundwater and reduce the volume of saltwater. Todd (1974)

discussed various means of preventing saltwater from contaminating groundwater

sources including:

1. Reduction of the abstraction rates

2. Relocation of abstraction wells

3. Subsurface barriers

4. Natural recharge

5. Artificial recharge

6. Abstraction of saline water

7. Combination of injection and abstraction systems

Extensive research has been carried out to investigate saltwater intrusion in coastal

aquifers. However, only few models have been developed to study the control of

saltwater intrusion. These models use one or more of the previous measures to study

the control of saltwater intrusion. The reduction of abstraction rates aims to reduce the

pumping rates and use other water resources (Scholze et al. 2002). The relocation of

abstraction well aims to move the wells further inland (Sherif and Al-Rashed 2001).

Subsurface barriers aim to prevent the inflow of seawater into the basin (Harne et al.

2006). Natural recharge aims to recharge aquifers with additional surface water (Ru et

al. 2001). Artificial recharge aims to increase the groundwater levels, using surface

spread for unconfined aquifers and recharge wells for confined aquifers. The sources

of water for injection may be surface water, groundwater, treated wastewater or

desalinated water (Papadopoulou et al. 2005). The abstraction of saline water aims to

reduce the volume of saltwater by extracting brackish water from the aquifer (Sherif

and Hamza 2001). The combination of injection of freshwater and extraction of saline

6

water can reduce the volume of saltwater and increase the volume of freshwater

(Rastogi et al. 2004).

1.5 MOTIVATION FOR THE STUDY

Problems like extensive ground settlement occurs due to upon salinity intrusion from

pumping of groundwater. Similarly, the groundwater level is drops continuously in

various parts of the coastal, due to excessive withdrawal for industrial and agricultural

purposes, causing intrusion of seawater toward land. Moreover, ground settlement

related problems and other problems should also be expected from sea level rise

because of global warming. Due to seawater intrusion there is a change in in-situ soil

properties and in laboratory for evaluating geoenvironmental properties ground water

or distilled water. But in-situ will be in interaction with different qualities of water.

1.6 OBJECTIVES OF THE STUDY

The objective of the present investigation is as follows:

1. To determine the characteristics of Seawater and Tap water.

2. To evaluate the geoenvironmental properties of soils with addition of Tap

water.

3. To study the impact of seawater intrusion on the geoenvironmental properties

of soils.

4. To compare the test results obtained with addition of Tap water and Seawater

to the soils.

1.7 ORGANIZATION OF THESIS

The thesis is organized in five chapters. Chapter 1 includes the introduction in which

the motivation and objectives for the present study is also discussed. Chapter 2 deals

with the review of literature. Chapter 3 gives with an overview of the methodology

adopted and the materials required for the study. The results and discussions are

compiled in chapter 4. Chapter 5 deals with the summary and conclusion of the study.

The organization of the thesis is shown in Fig 1.1

7

Fig 1.1 Organization of thesis

1. 8 SUMMARY

This chapter enumerates the effect of seawater on clay minerals, Causes of Seawater

intrusion and measures to control seawater intrusion .The motivation of the study and

objectives of the present study were also discussed.

Chapter 5

Summary and Conclusions, Scope of future work

Chapter 4

Results and discussion

Chapter 3

Materials and Methods

Chapter 2

Review of literature

Chapter 1

Introduction, Motivation, Objectives of the study

8

CHAPTER 2

LIERATURE REVIEW

2.1 GENERAL

(Mitchell,1976) characterized the different minerals present in the clay soil and the

bonding in the minerals and ability their participate in the cation exchange

reactions.(Lambe and Whitman, 1979) gave the variation of Atterberg limits based on

the minerals present in the soil and the ions exchanged during the interaction. Effect of

different salts and salt solutions on the geoenvironmental properties of soils given by

different authors has been discussed here.

2.2 CHARACTERIZATION OF FOUR CLAY MINERALS

Clay

Mineral

Chemical

designation

Bonds

between

layers

Ion exchange

Capacity of

Cation

Exchange

(meq /100g)

Illite

(K,H2O)2Si

(Al,Mg,Fe)4,6-

O20(OH)4

K-ions, strong

Some Si always

exchanged with

Al, K provides

balance between

the layers

0-40

Kaolinite

Al4Si4O10(OH)8

(SiAl)8(MgFe)6

O20(OH)4

O-OH, strong Al against silica

in 2:1 layer 3-15

Chlorite O20(OH)4 (2:1

layer)

(MgAl)6

(OH)12

Al against Mg in

Intermediate

layer

10-40

Montomor

illonite

Si8(Al3.34Mg0.66)

O20(OH)4

O-O, very

weak,

swellable

Mg exchanged

with Al 80-150

Table 2.1 Characterization of four Clay Minerals (after Mitchell, 1976)

9

2.3 EFFECT OF SEAWATER ON ATTERBERG LIMITS

The liquid limit and plastic limits of a type of soil can be correlated with various

engineering properties, such as permeability, shrinking and swelling behaviour, shear

strength, and compressibility of the soil. In addition the evolution of consistency limits

provides some very basic mechanical data about the soil and also gives a first insight

into the chemical reactivity of clays (Arasan and Yetimoglu, 2008; Shariatmadari et al

, 2011). Alamdar, 1991; Mahasneh, 2004; Mansour et al , 2008; Yukselen-Aksoy et al.,

2008; Arasan and Yetimoglu, 2008; have studied the effect of salt solutions on the

consistency limits of soil. The results have shown the liquid limit and plastic limit of

soil decrease as the salinity of pore fluid increases. Sivapullaiah and Manju, 2005, have

investigated the effect of NaOH solution on some geotechnical properties of the soil

with low plasticity (LL=38%). Their results have shown that the liquid limit of the soil

increases as NaOH solution concentration increases. The reason behind that is the

formation of a new swelling compound created by reaction of alkali solution with clay.

The effect of four salt solutions including NH4Cl, KCl, CuSO4 and FeSO4 on

consistency limits of CL clay and CH clay have been investigated by (Arasan and

Yetimoglu, 2008). Their experimental results indicate the liquid limit of CL clay

increases as the slat concentration increases whereas the liquid limit of CH clay

decreases as the slat concentration increases

(Kaya, 2008), Has studied the Seawater effect on consistency limits and compressibility

characteristics of clays. The results from his study indicate that the effect of seawater

is negligible on the tested consistency limits and compressibility characteristics of soils

when they have liquid limits up to 110%. The seawater effect is most noticed on the

consistency limits and compressibility of Na-bentonites. They also compared the results

with previous research. All reported data were normalized by dividing the index values

obtained using seawater by those obtained using distilled water. The comparison of data

indicate that the compiled data and present study data are in good agreement, i.e. when

the normalized values are plotted as function of liquid limit, all index properties plot

along the unity line until the liquid limit of soils is about 110%; then, the normalized

index values decrease almost linearly with liquid limit.

(Chittaranjan, 2011), Has studied effect of sea water on some geotechnical properties

of clayey soil. In this study soil which falls under CH group as per I.S classification is

used and geotechnical properties were discussed. The variation of liquid limit, plastic

10

limit and plasticity index with tap water and seawater, it is observed that the liquid limit,

plastic limit and plasticity index values of the contaminated soil increases when the

result of tap water is compared with the result of sea water. Liquid limit increased by

9.32% Plastic limit increased by 8% Plasticity index increased by 10.91.

(Ivasuc, 2012) Has studied the seawater influence on the behaviour of the expansive

clays. In his study four clayey soil samples were gathered with different mineralogy

and plasticity characteristics and tested to determine liquid limit in the presence of

distilled water, tap water and seawater. The results showed that The liquid limit

decrease in presence of seawater; values of all liquid limits in seawater are lower than

those in tap water. This difference can be seen more clearly for the bentonite sample.

Mineral Exchangable

Ion

Liquid

Limit

(%)

Plastic

Limit

(%)

Plasticity

Index

(%)

Shrinkage

Limit (%)

Montomoriilonite Na

K

Ca

Mg

Fe

Fea

710

660

510

410

290

140

54

98

81

60

75

73

656

562

429

350

215

67

9.9

9.3

10.5

14.7

10.3

-

Illite Na

K

Ca

Mg

Fe

Fea

120

120

100

95

110

79

53

60

45

46

49

46

67

60

55

49

61

33

15.4

17.5

16.8

14.7

15.3

-

Kaolinite Na

K

Ca

Mg

Fe

Fea

53

49

38

54

59

56

32

29

27

31

37

35

21

20

11

23

22

21

26.8

-

24.5

28.7

29.2

-

11

Table 2.2 Atterberg Limit of Clay Minerals (Lambe and Whitman, 1979)

( a Represents after five cycles of wetting and drying )

2.4 EFFECT OF SEAWATER ON SWELLING CHARACTERISTICS

(Chittaranjan, 2011), Has studied effect of sea water on some geotechnical properties

of clayey soil. In his study soil which falls under CH group as per I.S classification is

used and geotechnical properties were discussed the free swell index with tap water and

sea water It is observed that the free swell index increased 6.67% in seawater.

(Ivasuc, 2012), Has studied the seawater influence on the behavior of the expansive

clays. In his study the rate of change in swelling behavior of clayey soils when exposed

to seawater with respect to distilled water. The four clayey soil samples were gathered

with different mineralogy and plasticity characteristics and tested to swelling

characteristics in the presence of distilled water, tap water and seawater. The results

The differential free swell percent is lower than that in tap water and distilled water for

swelling soils (LL > 150...200 %), indicating reduction in swelling potential in

seawater, The difference in free swell percent between distilled water and seawater is

remarkable, between 0% to 200%; zero is for non-swelling soils and 200% is for

bentonite Clay .

2.5 EFFECT OF SEAWATER COMPACTION CHARACTERISTICS

Compaction tests were performed on dam construction materials. Soil compaction

improves strength characteristics of soil and consequently increases bearing capacity of

foundations constructed on it. Emami, 2008; Mansour et al., 2008 and Alainachi and

Alobaidy, 2010, have evaluated the effect of salinity on the compaction test results.

Their results showed that optimum moisture content decreases and maximum dry unit

weight of soil increases as the salinity of water increases.

(Chittaranjan, 2011), Has studied effect of sea water on some geotechnical properties

of clayey soil. In his study, soil falls under CH group as per I.S classification is used

Mineral Exchangable

Ion

Liquid

Limit

(%)

Plastic

Limit

(%)

Plasticity

Index

(%)

Shrinkage

Limit (%)

Attapulgite H 270 150 120 7.6

12

and geotechnical properties were discussed compaction characteristic like OMC, Dry

density and UCC, OMC increased by 30 % Dry density increased by 7.58%, UCC by

20% with seawater compared with tap water.

The effects of salt solution on shear strength of soil have been investigated by

Chattopadhyay, 1972; Di Maio and Fenelli, 1994; Alamdar, 1999; Tiwari et al., 2005;

Ayininuola et al., 2009; Naeini and Jahanfar, 2011 and Siddiqua et al., 2011. In their

studies, shear strength of soil has increased as concentration of water increased.

2.6 SUMMARY

The presence of different minerals present in the soils have significant effect on the

geoenvironmental properties and the bonding between the soil layers and the ions

responsible exchange reactions .Salts will show variation in the Atterberg limits,

maximum dry density and shear strength of soils

13

CHAPTER 3

MATERIALS AND METHODOLOGY

3.1 GENERAL

In the previous chapter, based on the previous reports the effect of seawater on different

soils and the changes in the geoenvironmental properties have been discussed. In this

study Low Compressible Clay, Clayey sand, High Compressible Clay soils have been

used for evaluating the impact of Seawater intrusion on geoenvironmental properties.

3.2 METHODOLOGY

The flowchart for methodology adopted in the current study is summarised in Fig 3.1

Fig.3.1. Flowchart for Methodology

Effect on Undrained shear strength of soils with the addition of Tap water and Seawater

Effect on Compaction chracteristics of soils with the addition of Tap water and Seawater

Effect on consistency limits of soils with the addition of Tap water and Seawater

Seawater and Tapwater characteristics

Soil Characterization by sieve analysis and Consistency limits

Collection of different soil samples

14

3.4 CLASSIFICATION OF SOILS

Type of soil Classification criteria

Low Compressible Clay Liquid Limit less than 35%

Above A line and Hatched zone on the

plasticity chart

Clayey sand More than 12% finer than 75µ size

Atterberg limits above A line with Ip

greater than 7

High Compressible Clay Liquid Limit greater than 50%

Above A line anon the plasticity chart

Table 3.1 Classification of soils

3.4 DETERMINATION OF CONSISTENCY LIMITS

3.4.1 LIQUID LIMIT TEST

Liquid limit is significant to know the stress history and general properties of the soil

met with construction. From the results of liquid limit the compression index may be

estimated. The compression index value will help us in settlement analysis. If the

natural moisture content of soil is closer to liquid limit, the soil can be considered as

soft if the moisture content is lesser than liquids limit, the soil can be considered as soft

if the moisture content is lesser than liquid limit. The soil is brittle and stiffer.

The liquid limit is the moisture content at which the groove, formed by a standard tool

into the sample of soil taken in the standard cup, closes for 10 mm on being given 25

blows in a standard manner. At this limit the soil possess low shear strength.

APPARATUS REQUIRED

Balance

Liquid limit device (Casagrande)

Grooving tool

Mixing dishes

Spatula

15

Electrical Oven

About 120 gm of air-dried soil from thoroughly mixed portion of material passing 425

micron I.S sieve is to be obtained. Distilled water is mixed to the soil thus obtained in

a mixing disc to form uniform paste. The paste shall have a consistency that would

require 30 to 35 drops of cup to cause closer of standard groove for sufficient length.

A portion of the paste is placed in the cup of liquid limit device and spread into portion

with few strokes of spatula. Trim it to a depth of 1cm at the point of maximum thickness

and return excess of soil to the dish. The soil in the cup shall be divided by the firm

strokes of the grooving tool along the diameter through the centre line of the follower

so that clean sharp groove of proper dimension is formed. Lift and drop the cup by

turning crank at the rate of two revolutions per second until the two halves of soil cake

come in contact with each other for a length of about 1 cm by flow only. The number

of blows required to cause the groove close for about 1 cm shall be recorded. A

representative portion of soil is taken from the cup for water content determination.

Repeat the test with different moisture contents at least three more times for blows

between 10 and 40.

Draw a graph showing the relationship between water content (on y-axis) and number

of blows (on x-axis) on semi-log graph. The curve obtained is called flow curve. The

moisture content corresponding to 25 drops (blows) as read from the represents liquid

limit. It is usually expressed to the nearest whole number.

3.4.2 PLASTIC LIMIT TEST

Helps in selection of soils used for making bricks, tiles, soil cement blocks in addition

to its use as foundation for structures.

APPARATUS REQUIRED

Porcelain dish.

Glass plate for rolling the specimen.

Air tight containers to determine the moisture content.

Balance of capacity 200gm and sensitive to 0.01gm

Oven thermostatically controlled with interior of non-corroding material to

maintain the temperature around 1050 and 1100C.

16

Take about 20gm of thoroughly mixed portion of the material passing through 425

micron I.S. sieve obtained in accordance with I.S. 2720 (part 1). Mix it thoroughly

with distilled water in the evaporating dish till the soil mass becomes plastic enough

to be easily moulded with fingers. Allow it to season for sufficient time (for 24 hrs)

to allow water to permeate throughout the soil mass Take about 10gms of this plastic

soil mass and roll it between fingers and glass plate with just sufficient pressure to roll

the mass into a threaded of uniform diameter throughout its length. The rate of rolling

shall be between 60 and 90 strokes per minute. Continue rolling till you get a threaded

of 3 mm diameter. Kneed the soil together to a uniform mass and re-roll. Continue

the process until the thread crumbles when the diameter is 3 mm. Collect the pieces of

the crumbled thread in air tight container for moisture content determination. Repeat

the test to atleast 3 times and take the average of the results calculated to the nearest

whole number.

3.5 PROCTOR TEST

This method helps in the determination of the relationship between the moisture content

and density of soils compacted in a mould of a given size with a 2.5 kg rammer dropped

from a height of 30 cm.

APPARATUS

Proctor mould having a capacity of 944 cc with an internal diameter of 10.2 cm

and a height of 11.6 cm. The mould shall have a detachable collar assembly and

a detachable base plate.

Rammer: A mechanical operated metal rammer having a 5.08 cm diameter face

and a weight of 2.5 kg. The rammer shall be equipped with a suitable

arrangement to control the height of drop to a free fall of 30 cm.

Sample extruder.

A balance of 15 kg capacity.

Sensitive balance.

Straight edge.

Graduated cylinder.

Mixing tools such as mixing pan, spoon, towel, spatula etc.

Moisture tins.

17

Take a representative oven-dried sample, approximately 2.5 kg in the given pan.

Thoroughly mix the sample with sufficient water to dampen it to approximately 4%

moisture content. Weigh the proctor mould without base plate and collar. Fix the collar

and base plate. Place the soil in the Proctor mould and compact it in 3 layers giving 25

blows per layer with the 2.5 kg rammer falling through. Remove the collar, trim the

compacted soil even with the top of the mould by means of the straight edge and weigh.

Divide the weight of the compacted specimen by 944 cc and record the result as the wet

weight γwet in grams per cubic centimetre of the compacted soil. Remove the sample

from the mould and slice vertically through and obtain a small sample for moisture

determination. Thoroughly break up the remainder of the material until it will pass a

no.4 sieve as judged by the eye. Add water in sufficient amounts to increase the

moisture content of the soil sample by one or two percentage points and repeat the

above procedure for each increment of water added. Continue this series of

determination until there is either a decrease or no change in the wet unit weight of the

compacted soil. The moisture content from soil sample kept in oven for 24hrs gives the

true moisture content. This moisture content helps in the dry unit weight γd of the soil.

Plot a graph between the moisture content and dry unit weight gives the Optimum

moisture content and Maximum dry density of soil.

3.6 UNCONFINED COMPRESSION TEST

Used to determine shear parameters of cohesive soil. It is not always possible to conduct

the bearing capacity test in the field. Sometimes it is cheaper to take the undisturbed

soil sample and test its strength in the laboratory. Also to choose the best material for

the embankment, one has to conduct strength tests on the samples selected. Under these

conditions it is easy to perform the unconfined compression test on undisturbed and

remoulded soil sample. Now we will investigate experimentally the strength of a given

soil sample.

Before starting of experiment diameter and length of the specimen were found out.

EQUIPMENT

Loading frame of capacity of 2 t, with constant rate of movement. What is the

least count of the dial gauge attached to the proving ring!

Proving ring of 0.01 kg sensitivity for soft soils; 0.05 kg for stiff soils.

Soil trimmer.

18

Frictionless end plates of 76 mm diameter (Perspex plate with silicon grease

coating).

Evaporating dish (Aluminium container).

Soil sample of 76 mm length.

Dial gauge (0.01 mm accuracy).

Balance of capacity 200 g and sensitivity to weigh 0.01 g.

Oven, thermostatically controlled with interior of non-corroding material to

maintain the temperature at the desired level. What is the range of the

temperature used for drying the soil

Sample extractor and split sampler.

Dial gauge (sensitivity 0.01mm).

Vernier callipers.

In this test, a cylinder of soil without lateral support is tested to failure in simple

compression, at a constant rate of strain. The compressive load per unit area required

to fail the specimen as called Unconfined compressive strength of the soil.

PREPARATION OF SOIL SAMPLE

Soil sample with optimum moisture content from proctor test with 3.8 cm diameter and

7.6 cm long was prepared. The sample was placed in position in the load frame. Dial

readings were converted to the appropriate load and length units, and entered these

values on the data sheet in the deformation and total load columns. Sample cross-

sectional area A0= (Π/4)*d2 was computed. Then strain, ε =ΔL/L0 was computed.

Corrected area, A'= A0 / (1-ε) was computed. Using A', specimen stress, Sc = P/ A' was

computed. Stress versus strain was plotted. Show qu as the peak stress (or at 15% strain)

of the test. Mohr’s circle was drawn using qu from the last step and show the undrained

shear strength, Su = C (or cohesion) = qu/ 2.

3.7 SUMMARY

In this chapter, characterization of soil samples and the test procedures for evaluating

the geoenvironmental properties such as consistency limits, standard proctor test,

unconfined compression test were discussed in this chapter.

19

CHAPTER 4

RESULTS AND DISCUSSION

4.1 GENERAL

The previous chapter discusses in detail the various materials and experimental

procedures that were referred in this study. Different soil samples were collected from

Asoor, Purathakudi, Pullambadi locations for the study. In this chapter the effect of

Seawater on the consistency limits, Optimum moisture content, Max dry density,

Undrained Shear strength on Low Compressible Clay, Clayey sand, High Compressible

Clay soils has been studied.

4.2 QUALITY PARAMETERS OF TAP WATER AND SEAWATER

Tap water from the water supply of National Institute of Technology, Tiruchirappalli

and Seawater from the Velaikkani was used in this study for evaluating the

geoenvironmental properties of soils. Table 4.1 represents the quality parameters of Tap

water and Seawater.

Table 4.1 Quality parameters of Tap water and Seawater

Parameter Tap water value Seawater value

pH 7.55 7.86

Chlorides 60 mg/L 12,410 mg/L

Sulphates 24 mg/L 3,292 mg/L

Calcium 42 mg/L 200 mg/L

Magnesium 5.6 mg/L 624 mg/L

Total Dissolved

Solids 380 mg/L 38,704 mg/L

20

4.3 EFFECT OF SEAWATER ON THE CONSISTENCY LIMITS

Location Soil Specific

Gravity

Water

Used LL (%) PL (%)

Plasticity

Index(PI)

Asoor

SC

2.63

Tap water

25

15

10

Seawater 20 16 4

Purathakudi

CL

2.5

Tap water

23

17

6

Seawater 18 17 1

Pullambadi

CH

2.82

Tap water

60

28

32

Seawater 48 25 23

Table 4.2 Variation of Liquid limit, Plastic Limit on different soils with the

addition of Tap water and Seawater

Above table shows the variation of Liquid limit, Plastic limit with the addition of tap

water and seawater. Plasticity index of the clayey sand, Low compressible clay and

High compressible clay reduced from 10% to 4%, 6% to 1% and 32% to 23% when

mixed with tap water and seawater respectively.

Mansour et al., 2008 have indicated that the presence of high valence exchangeable

cations in seawater decrease the distance between particles by decreasing the repulsive

forces in the soil microstructure. This causes the Vander Waals attractive force to be

dominant, hence increasing of capillary stress that formed between particles boundaries

and finally forming the aggregation.

21

4.4 EFFECT OF SEAWATER ON THE COMPACTION CHARACTERISTICS

Fig 4.1 Compaction curves for CL using Tap water and Seawater

The above graph represents the Variation of OMC and Maximum dry density for CL

soil with addition of Tap water and Seawater. With the addition of seawater to the Low

Compressible clay the optimum moisture content increased from 13.5% to 15%. This

resulted in the decrease in the maximum dry density from 1.96 g/cc to 1.94 g/cc. This

may be due to repulsive force between the salt molecules and the clay intermolecular

structure, causing an increase in the intermolecular distances and an increase in the void

ratios

Fig 4.2 Compaction curves for SC using Tap water and Seawater

1.5

1.55

1.6

1.65

1.7

1.75

1.8

1.85

1.9

1.95

2

4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00 20.00

Dry

un

it w

eigh

t(g/c

c)

Moisture content (%)

Tap water Seawater

1.5

1.6

1.7

1.8

1.9

2

2.1

2.2

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Dry

un

it w

eigh

t(g/c

c)

Moisture content (%)

Tap water

22

The above graph represents the Variation of OMC and Maximum dry density for SC

soil with addition of Tap water and Seawater. With the addition of seawater to the Low

Compressible clay the optimum moisture content decreased from 9.5% to 9.%. This

resulted in the increase in the maximum dry density from 1.94 g/cc to 2.16 g/cc.

This may be due to chemical reaction between the salt molecules and soil particles,

which partially contains lime. Sodium, potassium and magnesium chlorides from salt

reacts with calcium oxides and hydroxides from soil to form calcium chloride, which

hardens the soil and increases the dry unit weight.

Fig 4.3 Compaction curves for CH using Tap water and Seawater

The above graph represents the Variation of OMC and Maximum dry density for CL

soil with addition of Tap water and Seawater. With the addition of seawater to the Low

Compressible clay the optimum moisture content increased from 16% to 19%. This

resulted in the increase in the maximum dry density from 1.68 g/cc to 1.7 g/cc.

This may be due to chemical reaction between the salt molecules and soil particles,

which partially contains lime. Sodium, potassium and magnesium chlorides from salt

reacts with calcium oxides and hydroxides from soil to form calcium chloride, which

hardens the soil and increases the dry unit weight.

1.45

1.5

1.55

1.6

1.65

1.7

1.75

7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4 2 5

Dry

un

it w

eigh

t(g/c

c)

Moisture content (%)

Tap water

23

4.5 EFFECT OF SEAWATER ON THE UNCONFINED COMPRESSIVE

STRENGTH

The Unconfined compression test is conducted on the soil sample which has been

prepared with the help of optimum moisture content obtained from the proctor test

In the case of CH clay, the Unconfined compressive strength increased from 188.91 to

233.89 KPa with the addition of Seawater. High Compressible clay has multi layers of

gibbsite and silica sheets with hydrogen bonding linking these sheets. Upon axial

compression when treated with seawater, these sheets become closer to each other and

the tendency of these sheets to resist compression is high, which leads to higher

strength.

Fig 4.4 Stress Strain relation for CH using Tap water and Seawater

Fig 4.5 Stress Strain relation for CL using Tap water and Seawater

0

20

40

60

80

100

120

140

160

180

200

220

240

260

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

Axia

l st

ress

(kp

a)

Axial strain (%)

SeawaterTapwater

0

5

10

15

20

25

30

35

40

45

50

55

0 1 2 3 4 5 6 7 8 9 10 11 12 13

Axia

l st

ress

(kp

a)

Axial strain (%)

Tapwater seawater

24

The Unconfined compressive strength of Low Compressible clay decreased from 50.26

to 31.4 KPa with the addition of Seawater. the formation of dispersed structure (e-e or

f-f) on interaction with seawater which is unstable which leads to decrease in strength.

Fig 4.6 Stress Strain relation for Clayey sand using Tap water and Seawater

The Unconfined compressive strength of Clayey sand decreased from 57.51 to

27.84KPa with the addition of Seawater. In case of Clayey sand, cohesion is due to

presence of small quantity of clay. On interaction of soil with denser seawater particles

there is collapse in the honeycombed structure. Due to this there is a decrease in

strength.

Fig 4.7 Variation of Undrained shear strength for different soils with addition of

tap water and seawater

0

5

10

15

20

25

30

35

40

45

50

55

0 1 2 3 4 5 6 7 8

Axia

l st

ress

(kp

a)

Axial strain (%)

Seawater

Tapwater

25.13 28.75

94.45

15.7 13.92

116.94

10

50

100

150

CL soil SC soil CH soil

Un

dra

ined

sh

ear

stre

ngt

h

(kp

a) Tapwater Seawater

25

In the case of CH clay, the Undrained shear strength increased from 94.45 to 116.94

KPa in Low Compressible clay decreased from 25.13 to 15.7 KPa, in Clayey sand

decreased from 28.75 to 13.92 KPa with the addition of Seawater.

4.6 SUMMARY

Effect of Seawater on the consistency limits, Optimum moisture content, Max dry

density, Undrained Shear strength on Low Compressible Clay, Clayey sand, High

Compressible Clay soils has been studied and the test results are shown.

26

CHAPTER 5

SUMMARY AND CONCLUSIONS

5.1 SUMMARY

The objective of the study to was to find out the effect of Seawater on various

geoenvironmental properties on Low Compressible Clay, Clayey sand, High

Compressible clay soils. The effect of various properties such as liquid limit, plastic

limit, optimum moisture content, maximum dry density, Undrained shear strength were

studied and the results of the same were discussed in chapter 4.

5.2 CONCLUSIONS

1. The high compressible clay gave the highest specific gravity of 2.82, while the

Low compressible Clay gave the lowest specific gravity of 2.50.

2. When mixed with tap water High compressible clay gave the highest liquid and

plastic limits, while Low compressible clay gave the lowest values.

3. Plasticity index of the clayey sand, Low compressible clay and High

compressible clay reduced from 10% to 4%, 6% to 1% and 32% to 23% when

mixed with Tap water and Seawater respectively.

4. Plasticity index of the Clayey sand, Low compressible clay and High

compressible clay reduced from 10% to 4%, 6% to 1% and 32% to 23% when

mixed with tap water and Seawater respectively. Using Sea water, maximum

dry unit weight for the Low compressible clay was decreased from 1.96 g/cc to

1.94 g/cc, but increased that of clayey sand, and High compressible clay from

1.94 g/cc to 2,16 g/cc, 1.68 g/cc to 23.2 g/cc respectively.

5. This may be due to repulsive force between the salt molecules and the clay

intermolecular structure, causing an increase in the intermolecular distances and

an increase in the void ratios.

6. Whereas, the increase in the dry unit weight of the Clayey sand, Low and High

compressible clay could be as a result of a chemical reaction between the salt

molecules and soil particles, which partially contains lime.

7. Sodium, potassium and magnesium chlorides from salt reacts with calcium

oxides and hydroxides from soil to form calcium chloride, which hardens the

soil and increases the dry unit weight.

27

8. In the case of CH clay, the Undrained shear strength increased from 94.45 to

116.94 KPa with the addition of Seawater.

9. The Undrained shear strength of CL, SC soils decreased from 25.13 to 15.7

KPa, 28.75 to 13.92 KPa respectively with the addition of Seawater.

10. CH soil has multi layers of gibbsite and silica sheets with hydrogen bonding

linking these sheets. Upon axial compression when treated with seawater, these

sheets become closer to each other and the tendency of these sheets to resist

compression is high, which leads to higher strength.

11. In case of Sc, cohesion is due to presence of small quantity of clay. On

interaction of soil with denser seawater particles there is collapse in the

honeycombed structure. Due to this there is a decrease in strength.

12. In case of CL soil, the formation of dispersed structure (edge to edge or face to

face) on interaction with seawater which is unstable which leads to decrease in

strength.

5.3 SCOPE OF FUTURE WORK

To study the effect of Seawater on various geoenvironmental properties such as

swelling chracteristics, Compressibility characteristics, infiltration, Shear strength of

soils at different conditions. A study on the consistency limits, Unconfined compression

strength, Compaction has been carried out in this study

28

REFERENCES

Dorothy Caroll , Harry C Starkey, Effect of sea-water on clay minerals,

U.S. Geological Survey, Washington D.C.

Chen, J., Anadarajah, 1998. Influence of pore fluid composition on volume

of sediments in kaolinite suspensions. Clays and Clay Minerals, 46 (2), 145–

152.

Binod Tiwari, Gyanu Ratna Tuladhar; and Hideaki Marui (2005),

Variation in Residual Shear Strength of the Soil with the Salinity of Pore

Fluid, 10.1061/(ASCE)1090-0241131:12(1445).

Anil Kumar Mishra, Masami Ohtsubo, Loretta LI and Takahiro Higashi

(2005), Effect of Salt Concentrations on the Permeability and Compressibility

of Soil-Bentonite Mixtures, J. Fac. Agr., Kyushu Univ., 50 (2), 837-849.

Yeliz Yuk selen-Ak soy , Abidin Kaya , Ali Hakan Ören (2008), Seawater

effect on consistency limits and compressibility characteristics of clays,

Engineering Geology 102 (2008) 54–61

Seracettin Arasan, Temel Yetimoglu (2008) , Effect of inorganic salt

solution on consistency limits of clay ,Turkish J. Eng. Env. Sci. 32, 107 –

115.

Behzad Fatahi , Hadi Khabbaz and Sudip Basack (2011) , Effects of

salinity and sand content on liquid limit and hydraulic conductivity,

Australian Geomechanics Vol 46 .

P. D. Arumairaj. A. Sivajothi [2011] , Effect of Sea Water on Expansive

Soils, EJGE Vol. 15

Tatiana Ivasuc, (2012), Seawater influence on the behavior of the expansive

clays, Environmental Engineering. Vol. I, 2012.

S .A. Naeini, M. A. Jahanfar, (2011), Effect of Salt Solution and Plasticity

Index on undrained Shear Strength of Clays, World Academy of Science,

Engineering and Technology ,Vol:5

Rassoul Ajalloeian, Hadiseh Mansouri, Amir Hossein Sadeghpour [2013],

Effect of Saline Water on Geotechnical Properties of Fine-grained Soil, EJGE

Vol. 18

G. R. Otoko (2014), The Effect of Salt Water on the Physical Properties,

Compaction Characteristics and Unconfined Compressive Strength of a Clay,

29

Clayey Sand and Base Course, European International Journal of Science

and Technology, Vol. 3 No. 2, March, 2014.

M.E. Elmashad, A.A . Ata (2015), Effect of seawater on consistency ,

infiltration rate and swelling characteristics of montmorillonite clay, HBRC

Journal

Peng Chang-sheng, Low G kathleen, Zhang Qian( 2009), Effects of water

salinity and content on particle size distribution and soil strength, Journal of

Environmental Science and Engineering, Jan. 2009, Volume 3, No.1 (Serial

No.14)

Ayininuola Gbenga Matthew and Agbede Oluwole Akinyele ( 2014),

Sodium and Calcium Salts Impact on Soil Permeability, Journal of Earth

Sciences and Geotechnical Engineering, vol. 4, no. 3, 2014.

M. Chittaranjan, T. Srikanth, B. Yamini Lakshmi & D. Pavani, Effect of

sea water on some geo technical properties of clayey soil, International

Journal of Earth Sciences and Engineering, Vol 04, 2011.

Tamadher T. Abood, Anuar Bin kasa, Zamri Bin Chik, Effect of adding

three chloride compounds (NaCl, MgCl2, CaCl2) on the properties of silty clay

soil Journal of Engineering Science and Technology ,Vol. 2, No. 1 (2007)

102-110.

Abbasi, N., “The Role of Anions in the Dispersion Potential of Clayey

Soil,” Journal of Agricultureal Engineering Research, 12. (In pertioan),

2011.

Alainachi, I. H., and G.A. Alobaidy., The Effects of Basra Gulf Salt Water

on The Proctor Compaction and CBR Test Results of SoilSamples at Baniyas

City, Abu Dhabi, UAE, Electronic Journal of Geotechnical Engineering,

15., 2010.

Arasan, S., and T. Yetimoglu., Effect of Inorganic Salt Solutions on the

Consistency Limits of Two Clays, Turkish J. Eng. Env. Sci, 32, 107-115.,

2008.

Ayenu-Prah, Jr. A. Y., Effect of the Chemical Composition of Compaction

Water on the Performance of Soil Subgrades and Embankments, M.Sc.

Thesis,Texas Tech University, 62 P, 2004.

30

Ayininuola, G. M., O. A., Agbede and S. O. Franklin., Influence of

Calcium Sulphate on Subsoil Cohesion and Angle of Friction,” Journal of

Applied Sciences Research, 5, 297-304, 2009.

Chaudhari, S., Saturated Hydraulic Conductivity, Dispersion, Swelling, and

Exchangeable Sodium Percentage of Different Textured Soils as Influenced by

Water Quality, Communications in Soil Science and Plant Analysis, 32,

2439-2455, 2001.

Bale Nikhil Kumar, Jeevana Smitha , Dr. K V Uday, Effect of Salinity on

Geotechnical Properties of Expansive Soils, International Journal of

Innovative Research in Science,Engineering and Technology, Vol. 4, Issue

7, July 2015

Moyayed, R.Z., Haratian, M. and Izadi, E. (2011). “Improvement of

Volume Change Characteristics of Saline Clayey Soils”, Jnl. of Applied

Sciences. 11(1), 76-85

Zhou, J., Zheng, X., Flury, M. and Lin, G. (2009). “Permeability Changes

during Remediation of an Aquifer Affected by Sea-water”, J. Hydrology. 376,

557-566.

ASTM D4318 (2010), Standard Test Methods for Liquid Limit, Plastic Limit,

and Plasticity Index of Soils, ASTM International

B.L. Kirov1, N.N. Truc1” A study on the relationship between geotechnical

properties and clay mineral composition of Hanoi soft soils in saline media”

International Journal of Civil Engineering, December 2011.

P. G. Studds, D. I. Stewart and T. W. Cousens, The effects of salt solutions

on the properties of bentonite-sand mixtures, Clay Minerals,1998.

A.K. Mishra, Effect of bentonite quality on the hydraulic and compressibility

behaviour of soil-bentonite mixtures in the presence of salt solution, 2011