soil classifications

7/27/2019 Soil Classifications

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Soil Mechanics1CE - 6201

1

Courtesy BS M Nazmul Haqu

Course Teacher

Dr. Md. Mokhlesur Rahma

Professo

Department of Civil Engineerin

DUE

Soil Classification

Soil classification according to their origin and mode

Soil Classify

Inorganic Origin,Inorganic Soil

Organic Origin,Organic Soil

Muck PeatResidual Soil Transported Soil

Black Cotton Soil Lateritics, Coarse Grained

Soil, Have not swellingproperties

Lateritics, Fine Grained Soil,

Have swelling properties

Water Transported Glacier Transported Wind Transported Gravity Transported

Water transported soil

1. Alluvial soil: If soil is deposited by running water.2. Lacustrine soil: If soil is deposited by standing water.3. Marine soil

a. Offshore deposit, takes place in relatively still water below zone of wave action.b. Shore deposit, form from many different shore currents and wave action.

Wind transported soil

1. Aeolian soila. Dunes, in higher proportion, sand deposit.b. Loess, in higher proportion, silt deposit. Saturated loess is collapsible soil.c. Tuff, in higher proportion, ash deposit.

Gravity transported soil

Colluviums soil Talus (Formed by Landslides)


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Classification and IndexProperties

(, , , G, n, LL, PL, SL etc)

Classification System("Language")

Engineering Properties

(Permeability, Compressibility,Shrinkage Swell, Shear Strength)

Engineering Purpose

(Highways, Airfields,Foundaiton, Dams etc)

Glacier Transported soil

1. Glacial till, form from melting ice-water depositing soil.2. Moraine, direct deposits of glacier.3. Drift4. Eskers, 10 m to 30 m high and 0.5 to several km long form small tiller.5. Drumlins, 1070 m height and 200800 m long.6. Erraties7. Hardpan, Glacier soil of hard stiffness.8. Varved clay, 3 mm or 1/8 thick or more.

The roles of soil classification system in geotechnical engineering

Systems of soil classification

The Unified Soil Classification System (USCS) The American Association of State Highway and Transportation Officials (AASHTO) Federal Aviation Administration (FAA) Massachusetts Institute of Technology (MIT) or The British Standard Institute (BSI) American Society of Testing and Materials (ASTM)

International System (IS) Unified soil Bureau of Reclamation (USBR)


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USCS

75 19 4.75 2.0 0.425 0.075

Gravel Sand

Fines

Silt and Clay

C F C M F

AASHTO

75 2.0 0.425 0.075

Gravel SandSilt and Clay

C F

MIT

2.0 0.6 0.06

Gravel Sand Silt

C F

Clay

0.2

M

0.02 0.006 0.002 0.0006 0.0002

C FM C FCM

IS

0.1 0.05

Glacial Silt Silt

C F

Clay

0.02 0.006 0.002 0.0006 0.0002

C U FM

Sand

2.0

V C

1.0 0.5 0.2

C M F C F

ASTM

0.425

Fine

SandSilt

0.075 0.005

Gravel

2.0

Medium

Sand

0.001

ClayCollodial

Clay

FAA Silt

0.075 0.005

Gravel

2.0

Sand Clay

C - Coarse

M - Medium

F - FineVC - Very Coarse

FC - Fine Collidal

UF - Ultra Fine

FAA - Federal Aviation Administration

USCS - Unified Soil Classification System

AASHTO - American Association of State Highway and Transportation Officials

MIT - Massachusetts Institute of Technology

ASTM - American Society for Testing and MaterialsIS - International Standard

Soil Grain Size in mm

75 4.75 0.075100 0.0002


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Four type of common soil

Gravel Sand Silt Clay

Soil classification depending on cohesive properties

Cohesive soilo Gravelo Sando Non Plastic (NP) silt

Cohesive soilo Plastic silto Clay

Uses of soil classification

Foundation design (USCS system)

Highway design (AASHTO system) Airport design (AASHTO system) Agricultural field (USBR system)

Soil tests required for classification

Grain size analysiso Sieve analysiso Hydrometer analysis

Consistency testso Liquid limit testo Plastic limit test

Condition of General Design

Economy Shear failure / shear strength Excess settlement / consolidation properties

Effective Size

This parameter is the diameter in the particle size distribution curve corresponding to l0%

finer. The effective size of a granular soil is a good measure to estimate the hydrauli

conductivity and drainage through soil

Determination of granular or sandy soil whether it is poor or well graded

The co-efficient of uniformity,

The co-efficient of curvature,


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0

10%

20%

40%

30%

50%

60%

%FinerbyMass

70%

80%

90%

100%

Grain Size, D (mm)

10 1

10D60D 30D

0.1

Where , and are the diameters corresponding to percents finer than 60, 30, and10% respectively.

For, Gravel when well-graded,

Otherwise Gravel is poor graded.

For, Sand when well-graded,

Otherwise Sand is poor graded.

Plasticity of soil

The plasticity of a soil is its ability to undergo deformation without cracking or fracturing. A

plastic soil can be molded into various shapes when it is wet. Plasticity is an important index

property of fine grained soils, especially clayey soils.

Atterberg limits or Consistency Limits of soil

The moisture contents of a soil at the points where it changes from one state to the other ar

called consistency limits or Atterberg limits.

On the other hand, The moisture content, in percent, at which the soil changes from a liqui

to a plastic state, is defined as the liquid limit (LL). The moisture content, in percent, at which

the soil changes from a plastic to a semisolid state and from a semisolid to a solid state ar

defined as the plastic limit (PL) and the shrinkage limit (SL), respectively. These limits ar

referred to as Atterberg limits.


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Atterberg Limits used for

To describe the consistency of fine-grained soils To determines its state or consistency Four states are used to describe the soil consistency; solid, semi-solid, plastic and

liquid

To defining or classifying a soil type or predicting soil performance when used construction material.

Brittle Solid Semi Solid Plastic Solid LiquidState

Water Content,0 SL PL LL

W < PL

W > LLW LL

W PL

Liquidity Index LI < 0 LI = 0 LI > 10 < LI < 1 LI = 1

Stress - StrainDiagram of soil

at various state

Figure: Water content and stress strain graph at various state

Liquid Limit

The increasing moisture content, in percent, at which the soil changes from a plastic to liquistate, is defined as the liquid limit (LL). It offers no shearing resistance and can flow likliquids. The liquid limit of a soil is determined by Casagrandes liquid device (ASTM- D-4318

and is defined as the moisture content at which a groove closure of 12.7 mm or inchoccurs at 25 blows.

Plastic limit

The increasing moisture content, in percent, at which the soil changes from a semisolid tplastic state, is defined as the plastic limit (PL). The soil in the plastic state can be moldedinto various shapes. The Plastic limit of a soil is determined by Casagrandes liquid devic(ASTM- D-4318) and is defined as the moisture content at which the soil crumbles when

rolled into a thread of 3.18 mm in diameter.

Shrinkage limit

The increasing moisture content, in percent, at which the soil changes from a solid to

semisolid state is defined as the shrinkage limit (SL). The shrinkage limit is determined by th

moisture content at which the soil does not undergo any further change in volume with loss omoisture (ASTM - D-427).

Plasticity Index

The difference between the liquid limit and the plastic limit of a soil is defined as the plasticit

index, PI

PI = LLPL.


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Liquidity Index

The relative consistency of a cohesive soil in the natural state can be defined by a ratio calle

the liquidity index, which is given by

Where,

Shrinkage Limit Plastic Limit Liquid Limit

Solid Semi-Solid LiquidPlastic

Increasing Moisture

Volume

Drying

The ranges of Liquid limits and Plastic Limits

The range of liquid limit can be from zero to 1000, but most soils have LL less tha100.

The Plastic Limit can range from Zero the 100 or more, with most being less than 40.Determination of Liquid Limit & Plastic Limit

Liquid Limit

The increasing moisture content, in percent, at which the soil changes from a plastic to liquistate, is defined as the liquid limit (LL). It offers no shearing resistance and can flow likliquids. The liquid limit of a soil is determined by Casagrandes liquid device (ASTM- D-4318

and is defined as the moisture content at which a groove closure of 12.7 mm or incoccurs at 25 blows.

The liquid limit (LL) is the water content at which a soil changes from plastic to liquibehavior. The original liquid limit test of Atterberg's involved mixing a pat of clay in a roundbottomed porcelain bowl of 10-12cm diameter. Soil is placed into the metal cup portion of thdevice and a groove is made down its center with a standardized tool of 13.5 millimeter(0.53 in) width. The cup is repeatedly dropped 10mm onto a hard rubber base at a rate of 12blows per minute, during which the groove closes up gradually as a result of the impact. Thnumber of blows for the groove to close is recorded. The moisture content at which it takes 25drops of the cup to cause the groove to close over a distance of 13.5 millimeters (0.53 in) idefined as the liquid limit. The test is normally run at several moisture contents, Liquid limiis determined by plotting a flow curve on a semi -log graph, with no. of blows in log scale anthe water content as ordinate and drawing the best straight line through the plotted points.


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Plastic limit

The increasing moisture content, in percent, at which the soil changes from a semisolid tplastic state, is defined as the plastic limit (PL).

The soil in the plastic state can be molded into various shapes. The Plastic limit of a soil idetermined by Casagrandes liquid device (ASTM- D-4318) and is defined as the moistur

content at which the soil crumbles when rolled into a thread of 3.18 mm or in diameter.

soil is considered non-plastic if a thread cannot be rolled out down to 3mm at any moisture.

Hard Rubber Base50 mm

150 mm

Soil 54 mm

22 mm

125 mm

Liquid Limit Apparatus

2 mm

8 mm

20 mm50 mm

20 mm

20 mm

45

10 mm

Casagrande Tool

Divied Soil Cake Before Test Divied Soil Cake After Test

Hard Rubber Base


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Liquid Limit

One Point MethodThe determination of liquid limit as explained earlier requires a considerable amount of timand labor. We can use what is termed the 'one-point method' if an approximate value of thlimit is required. The formula used for this purpose is

Where,

Cone Penetrometer method

The soil whose liquid limit is to be determined is mixed well into a soft consistency anpressed into the cylindrical mold of 5 cm diameter and 5 cm high. The cone which has acentral angle of 30 and a total mass including cone, sliding rod and the disk is 80 0.05 gmwill be kept free on the surface of the soil. The depth of penetration 3; of the cone is measurein mm on the graduated scale after 30 sec of penetration. The liquid limit LL ( may bcomputed by using the formula,

( )

30.5 mm

50 mm50 mm

Sliding RodTotal mass = 80 0.5 gm

Cylindrical mold

Calibrated Scale

30


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Where,

= The water content corresponding to the penetration y = Liquid Limity = Penetration in mm

Symbols used in the unified soil classification system

Soil Symbol

Gravel G

Sand S

Silt M

Clay C

Organic soil O

Peat Pt

Gradation Symbol

Well graded W

Poorly graded P

Low Plasticity L

High Plasticity H

Plasticity Chart and its Significance

A plasticity chart is used to differentiate the plasticity and organic characteristics of the fine

grained soils based on liquid limit (LL) and plasticity index.

Significance

Used in Unified Soil Classification System Used in AASHTO Soil Classification system Used for Silt-Clay Soil Classification

PlasticityIn

dex(%)

40

30

20

10

0

60

50

10

Liquid Limit (%)

20 30 40 50 60 70 80 90 100

U-Line

Inorganic Silts of Medium

Compressibility and Organic SiltsInorganic Silts of

Low Compressibility

Inorganic Silts of HighCompressibility and Organic

ClaysInorganic Clays

of Low Plasticity

Inorganic Clays of MediumPlasticity

Cohesionless

Soil

Inorganic Clays of High Plasticity

PI=0.9

(LL-

8)

A-L

ine

PI=0.7

3(LL

-20)

CL - ML

CL

ML

orOL

CI CH

MI

orOI

MH

orOH


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Field identification procedures for fine grained soil

These procedures are to be performed on the below #40 sieve particles, approximatel0.4 mm.

For field classification purposes, screening is not intended; simply remove by hand thcoarse particles that interfere with the tests.

Dry Strength test

It gives idea crushing characteristics. The part of the soil is completely dried by air drying, sun drying or oven drying. The dry strength is determined by breaking the dried pat and crumbling it betwee

fingers.

The dry strength is a measure of plasticity of the soil. The dry strength depends upon the colloidal fraction of the soil. The strength is termed; high, if the dried pat cannot be powdered at all; medium

considerable pressure is required; and low, if the dry pat can be powdered.

Dilatancy Test

It is the reaction of shaking. A small part of moist soil of about 5 ml in volume is prepared. Water is added to make the soil soft but not sticky. The pat is placed in the open palm of one hand and shaken horizontally striking by th

other hand at bottom of the palm at several times during shaking.

If the soil gives a positive reaction, the water appears on its surface which changes to lively consistency and appears glossy.

When the pat is squeezed between the fingers, the water appears and glossy disappeafrom the surface.

The larger size particles, the quicker is the reaction, called quick if water appears andisappears quickly.

The reaction is termed slow if water appears and disappears slowly. For no reaction, the water does not appear at the surface.

Results

Test ML CL OL MH CH OH MI CI OI

Dilatancy QuickNone to

veryslow

SlowSlow tonone

NoneNone to

VerySlow

Quickto

SlowNone Slow

Toughness None Medium Low High HighLow to

MediumNone Medium Low

DryStrength

Noneof low

Medium SlowLow to

Medium

Highto

VeryHigh

Mediumto High

LowMediumto High

Low toMedium


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Toughness test

The pat is rolled on a smooth surface or between the palms into a thread of about mm in diameter.

The thread is folded and re-rolled to reduce the water in soil, due to evaporation bheat of hand, until the 3 mm diameter thread just crumbles.

The water content at that stage is equal to the plastic limit and the resistance tmoulding at that stage is called the toughness.

Dual Symbol and Borderline Classification in USCS.

Soils having between 50% and 12% passing the #200 sieve are classified as Borderline and

have a symbol called dual symbol.

The first part of the dual symbol indicates whether the coarse fraction is well graded opoorly graded. The second part describes the nature of the fines.

For example, a soil classified as a SP-SM means that it is a poorly graded sand witbetween 5% and 12% silty fines.

Similarly, a GW-GC is a well graded gravel with some clayey fines that plot above the Aline.

Fine Grained SoilsCoarse Grained Soils

BorderlineCase

45 50 55

BorderlineCase

0 5 12 100

Percent Passing the #200 Sieve

Gravel

Sand

Silt

ML

GW

GP

SW

SP

Gravel

Sand

GM

GC

SM

SC

MH

OH

Clay

CL

CH

OL

Dual Symbol for 5% to 12% finer particles

Or

GW - GM SW - SM

GW - GC SW - SC

GP - GM SP - SM

GP - GC SP - SC

Dual Symbol for 45% to 55% finer particles

Or

GM - ML SM - ML

GM - MH SM - MH

GC - CL SC - CL

GC - CH SC - CH


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The limitations/criticism/drawback of USCS

Although the letter symbols in the USCS are convenient, they do not completeldescribe a soil or soil deposit.

In USCS, do not examine the characteristics as color, odor and homogeneity. In USCS, for coarse-grained soils such items as

o Grain shapeo Mineralogical contento Degree of weatheringo In situ densityo Degree of compaction

are do not express.

Adjectives such as rounded, angular and sub-granular are not used to describe inUSCS.

For the fine grained fraction a) natural water content and b) consistency do not bnoted.

Plasticity Chart for AASHTO Soil Classification System

Plastic

ityIndex(%)

40

30

20

10

0

60

50

10

Liquid Limit (%)

20 30 40 50 60 70 80 90 100

A - 6 and A - 2 - 6

A - 7 - 6

A - 4 and A - 2 - 4 A - 5 and A - 2 - 5

A - 7 - 5 and A - 2 - 7

PI=LL

-30


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Flow Chart of Unified Soil Classification System

Make visual examination of soil to determine whether

it is highly organic, coarse grained, or fine grained. In

borderline cases, determine amount passing through

the #200 sieve

Highly organic soils (Pt)

Fibrous texture, color, odor, very high moisture content,

particles of vegetable matter (sticks, leaves, and so forth)

More than 50% passes the #200 sieve50% or more retained on #200 sieve

Coarse Grained Fine Grained

Run LL and PL on minus

#40 sieve material.

Gravel (G) Sand (S)

Less than 5%

pass #200 sieve

% G > % S % S > % G

Run a Sieve Analysis

Between 5% and

12% pass #200 sieve

More than 12% pass

#200 sieve

Obtain C and C

from grain size graphc u Requires dual symbol

based on gradation and

plasticity characteristics

Run LL and Pl

on minus #40

sieve fraction

Well Graded Poorly Graded

GW GP

GW - GM

GP - GMGW - GCCP - GC

Below "A"

line or

hatched

zone on

plasticity

chart

Limits

plot in

hatched

zone on

plasticity

chart

Above "A"

line and

hatchedzone on

plasticity

chart

GM GM - GC GC

Less than 5%

pass #200 sieveBetween 5% and

12% pass #200 sieve

More than 12% pass

#200 sieve

Obtain C and C

from grain size graphc u

Requires dual symbol

based on gradation and

plasticity characteristics

Run LL and Pl

on minus #40

sieve fraction

Well Graded Poorly Graded

SW SP

SW - SM

SP - SMSW - SCSP - SC

Below "A"

line or

hatchedzone on

plasticity

chart

Limits

plot in

hatchedzone on

plasticity

chart

Above "A"

line and

hatchedzone on

plasticity

chart

SM SM - SC SC

LowLL

HighLL

LL < 50 LL > 50

Below "A"

line or PI 7

Color

or

odor

Organic Inorganic

OL MLML - CL CL

Below "A"

line on

plasticity

chart

Above

line o

plastic

char

Color

or

odor

Organic Inorganic

OH MH CH

Unified Soil Classification System


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Flow Chart of AASHTO Soil Classification

Make visual examination of soil to determine whether

it is highly organic, coarse grained, or fine grained. Inborderline cases, determine amount passing through

the #200 sieve

More than 36% passes the #200 sieve35% or Less passes the #200 sieve

Granular Material

Less than 25%pass #200 sieve

Run a Sieve Analysis

AASHTO Soil Classification System

A - 2


Run sieve analysis, Also

LL and Pl on minus #40sieve material

A - 1


Greater than 51%

pass #40 sieve

Less than 15%

pass #200 sieve,Less than 30%

pass #40 sieve,

Less than 50%pass #10 sieve,

PI less than 6

A - 1 - a

Less than 25%

pass #200 sieve,Less than 50%

pass #40 sieve,

PI less than 6

A - 1 - a

Less than 10%pass #200 sieve,

Non Plastic

A - 3

Run LL and PL on minus#40 sieve material.

SiltyPI < 10

ClayeyPI > 11

LL < 40 LL > 41

A - 2 - 4 A - 2 - 5

LL < 40 LL > 41

A - 2 - 6 A - 2 - 7

Silt-clay Material

Run LL and PL on minus#40 sieve material.

SiltyPI < 10

ClayeyPI > 11

LL < 40 LL > 41

A - 4 A - 5

LL < 40 A - 7LL > 41

A - 6

PI equal to orless than LL

minus 30

A - 7 - 5

PI Greater thaLL minus 30

A - 7 - 6


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Plasticity Chart for Classification of Clay Minerals

PlasticityIndex(%)

40

30

20

10

0

50

10

Liquid Limit (%)

20 30 40 50 60 70 80 90 100

U-Line

P

I=0.9(LL

-8)

A-Line

PI=0.73(L

L-20)

MontmorilloniteIllite

Kaolinite

Chlorite

Group Index

The group index is a means of rating the value of a soil as a sub-grade material within its ow

group.

It is a new factor used in the AASHTO soil classification system. It is not used in order to place a soil in a particular group that is done directly from th

results of sieve analysis, the liquid limit and plasticity index.

The higher the value of the group index, the poorer is the quality of the material. The group index is a function of the amount of material passing the # 200 sieve, th

liquid limit and the plasticity index.

Group Index

[ ]

Where,


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The value of Group Index should be reported to the nearest whole number but not fraction, say 15.2 15 or 15.6 16.

When the calculated Group Index is negative, shall be reported as 0 (zero). When PI = 0, then particle Group Index formula

[ ] When LL = 0, then particle Group Index formula

[]

The good qualities of a sub-grade material are related as inversely proportional to itGroup index.

For example, a Group Index the value of which is zero, generally indicates a excellensub-grade material.

A Group Index the value of which is 20 indicates a Poor material.Soil Rheology

Soil Rheology is the study of time dependent deformations of soil materials.

For the analysis, the real/physical soil system is placed by an ideal mechanical modecalled the Rheological model, composed of springs, dashpots and friction elements in

various combinations.

The three basic rheological models of practical interest are shown in figureSpring

a) Hookean model

Dashpot

b) Newtonian model c) Yield Stress model

y

These models characterize the stress strain relationship in terms of the materiaconstants known from experiments.

a) Hookean model: Represents a perfect elastic response of soindependent of time, i.e. stress in a linear function of strain, where, K = Spring constant or modulus of elasticity.

b) Newtonian models: Represents a perfect viscous response of soil, i.estress is a linear function of the rate of change in strain with respect t

time,

Where,

c) Yield stress models: the stress can be generate a strain only if Where, is a certain minimum stress necessary for causing strain

or slip.

is yield stress or frictional resistance.


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Significance of Liquidity Index, Consistency Index and Toughness Index of Soil

Liquidity Index is defined as

Significances of Liquidity Index

It indicates the nearness of its water content to it, liquid limit.When

LI = 100%, Soil behaves liquid and is at LL

LI = 0%, Soil is at PL

LI = -ve, Soil behaves hard, it indicates a water content < PL.

Consistency Index is defined as

Significances of Consistency Index

Consistency Index shows the nearness of water content of the soil to its Plastic Limit.When

CI = 0%, at LL

CI = 100% at LL = PL

CI > 100% at semisolid state

CI = -ve at water content > LL

LI high then CI low, vice versa.

Toughness Index is defined as

Significances

is a measure of shearing strength of the soil at PL. varies 0 to 3.0. < 1.0 the soil is brittle at het PL.

Flow Index

Flow Index is the slope of the flow curve obtained between the number of blow (abscissa = log

scale) and the water content in Casagrandes method of determination of the liquid limit a

figure.

Significances

is the rate at which a soil mass loses shear strength with an increases in watecontent.

is greater, shear strength lower.


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MoistureContent%

40

30

20

10

0

100

90

80

70

60

50

10

No of Blow, N (Log Scale)

N1

W1

W2 (1)

W3

W2 (2)

N2 N3

(1)

(2)

Figure: Flow Index

Activity of soil

The activity (A) of a soil is the ratio between

Plasticity Index and the percent of clay

fraction (F) (less than 2 m) present. The

range of activity of soil is between 1 -2.

When

A1.25 Soil is Active

Significance:

Activity of soil gives information about type

and effect of clay mineral of soil.

0

A(3)

Clay Fraction

Plas

ticityIndex(%)

20

40

60

80

10 20 30 40 50

A(2)

A(1)

Kaolinite

Illite

Montomor illonite


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Soil Sensitivity:

Soil sensitivity is the estimate of a soil's ability to maintain its original strength when

bothered or remolded.

The value of sensitivity varies in between 1 to 16.

Where,

Classification of Soils based on Sensitivity

Sensitivity Soil Type

16.0 Quick sensitive

When sensitivity of soil is greater than 8 soil must be treated for construction becaus

disturbance tends to transform them, at least temporarily, into viscous fluids, such a clay

montmorillonite group and posses flocculent structure.

Thixotropy

If a remoulded soil is allowed to stand without further disturbance and changed in wate

content, it may regain at least part of its original strength and stiffness. The increase in

strength of the soil is due to the gradual reorientation of the absorbed molecules of water with

passage of time is called thixotropy.

Engineering use of Consistency Limit

Both Plastic limit and Liquid limit gives the idea upon the type and amount of clay in soil. As grain size decreases, both PL and LL increase.

Plasticity chart plot of PL and LL is extremely useful for classification of fine grainesoils.

LL < 20%, soil is generally sands. Soils with high organic content have low Plasticity Index. Liquid Limit is a indicator of compressibility of a soil. i.e. . Shrinkage Index is a indicator for amount of clay and directly proportional to clay

fraction.

Toughness Index is a measure of shearing strength at PL. When comparing the properties of two soils with equal volume of plasticity Index, it i

found that as the liquid limit increases, the dry strength and toughness decrease

where as compressibility and permeability increases.


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When comparing the properties of two soils with equal volume of Liquid limit, it ifound that as the Plasticity Index increases, the dry strength and toughness increase

where as the permeability decreases but compressibility remains almost same.

Particle Size Decrease

PlasticLimit

Plasticity Index

Plastic Limit

Liquid Limit

Silt Clay


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Questions

Soil Classification

1. What are the main soil classification depending on origin and mode?2. What are modes of transported soil?3. What is water transported soil?4. Mention wind transported soils?5. Mention glacier transported soils.6. What are the roles of soil classification system in geotechnical engineering?7. What are the systems used of soil classification?8. What are the different soil size limits between USCS and AASHTO systems?9. What are the different soil size limits for ASTM and IS systems?10. Classify soil depending on cohesive property.11. What are engineering field, where soil classification used?12. What are the tests required for types of soil classification?13. On which condition general design on soil depended?14. How will you determine whether a gravel or sandy soil is poor or well graded?15. Define plasticity of soil.16. Define the consistency limits / Atterberg limits.17. Draw the stress - strain diagrams of soil at different limit limits and plastic limits.18. Define plastic limit and liquid limit.19. Define plasticity index and liquidity index.20.What are the ranges of liquid limit and plastic limit?21. Draw neat sketch of Casagrande device.22. State the Casagrande definition for liquid limit determination.23. State the Casagrande definition for plastic limit determination.24.Define one point method for liquid determination.25. State the cone penetrometer method with device for liquid limit determination.26.What are symbols used for unified soil classification?27.Draw plasticity chart.28.For what methods, the plasticity charts are used?29.What are the tests used for field identification of soils?30.State dry strength test of soils in field.31. State dilatancy test of soils in field.32. Compare the results for different field test for organic and inorganic clay and silt.33. Explain the application of A line on plasticity chart for unified classification.34.Explain the application of hatched zone on plasticity chart for unified classification.35. With example define the dual symbol for USCS soil classification.36.Explain the borderline classification in USCS soil classification.37. What are the drawback / limitations / criterion for unified soil classifications?


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23Courtesy B

38.Draw the plasticity chart for AASHTO soil classification system.39. Draw the plasticity chart for classification of clay minerals.40.Define group index with formula.41. Define partial group index formula.42.What are the significances for group index values for practical purposes?43.What are the difference between A 1 a and A 1 b soil?44.

What are the difference between A 2 4, A 2 5, A 2 6 and A 2 7 soils?

45.Define A 3 soil.46.What are the difference between A 4, A 5 and A 6 soils?47.What are the difference between A 7 5 and A 7 6 soils?48.What is meant by Soil Rheology and Rhecological model?49.Define the different rhecological models with figures.50.What are the significances of liquidity index?51. What are the significances of consistency index?52. What are the significances of toughness index?53. Define flow index with significance.54.State activity of soil.55. State sensitivity of soil.56.State thixotrophy of soil.57. What are the engineering uses of Atterbergs limits?58.What are the effects of plasticity index on engineering properties?

soil classifications

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