Sieve analysis is method of Particle size analysis by which we determine
amount of particles of different sizes present in a soil sample
Done for Coarse grain soils
In this method Soil is sieved through a set of sieves
>0.075mm
or
75
micron
Coarse Grained Fraction
Size of these openings give the sieves their
name , which is called sieve number
Sieves are wired
screens having
square openings
A sieve with a mesh
opening of 4.75 mm
Is designated as 4.75
mm sieve
Similarly a 600 micron sieve refers to a mesh
opening of 600 micron or 0.6 mm
Sieve analysis is done in 2 ways
Dry Sieve Analysis
Wet Sieve Analysis
We take roughly 500 gms of soil sample
It should not contain any lumps .
NO LUMPS
If it does , then lumps should be pulverized
We Take its weight and see this weight as W
This is sample is sieved through 4.75 mm sieve .
Portion of soil which is
retained on 4.75 mm sieve is
called gravel Fraction
Portion of soil which pass through
the sieve and contain particle size
less than 4.75 mm is called Sand
Fraction
Coarse Grain Soils are divided into 2 categories
1) Gravels having particle/grain size greater than 4.75 mm
2) Sands having particle/ grain size smaller than 4.75 mm
Gravels
Sand
Sieves are Wire screens having square openings
For Sieve Analysis we need 2 set of sieves
1) One is for Gravel Fraction
2) One is for Sand Fraction
Set of Coarse Sieves
80mm
40 mm
20 mm
4.75 mm
10 mm
Set of Fine Sieves
2 mm
1 mm
600 micron
425 micron
212 micron
150 micron
75 micron
600 micron = 0.6 mm
The sieves are stacked over
one another with increasing
size of mesh opening from
bottom to top
This means that sieve of
the smallest opening is
kept at bottom
Sieve of the largest
opening is kept at the top
Pan which has no opening is
placed below the bottom of the
sieve
Soil sample is place in the top sieve
Lid to cover this arrangement is
placed over the top most sieve
Whole assembly is placed on a mechanical
sieve shaker and shaked for 10 mins
Amount of soil retained on each sieve is
weighed to an accuracy of 0.1 gm
W1
W2
W3
W4
W5
W pan
Then we calculate % of
amount of soil retained
on each sieve
W1
W2
W3
W4
W5
W Pan
As weight of Retained soil
on each sieve divided by
total wait of soil Multiplied
by 100
This way we
know what % of
total weight is
retained on a
particular sieve
• .
PERCENTAGE WEIGHT RETAINED ON EACH SIEVE
W1
W2
W3
W4
W5
W Pan
𝑃 4=
𝑊 4
𝑊
𝑋 100
𝑃 5=
𝑊 5
𝑊
𝑋 100
𝑃 𝑃𝑎𝑛=
𝑊𝑝𝑎𝑛
𝑊
𝑋 100
For Calculation Purpose and to determine some
important characteristics we also calculate two Values
For Calculation Purposes & to
determine some important
characteristic of soil sample , we
calculate two Values
P4
P3 +
P 2+
P1+
Cumulative Percentage Retained
Let’s write our calculations in a table
Cumulative % retained is the total %amount
of soil which could not pass a particular sieve
In other words this % amount of soil has
grain size greater than this sieve
So Let’s Calculate cumulative % retained on every sieve
P1
P1 + P2
P1+P2+P3
P1+P2+P3+P4
P1+P2+P3+P4+P5
P1+P2+P3+P4+P5+Ppan
For Calculation Purpose , in addition to
Cumulative % retained , we also calculate
And we Plot a Graph Called as
% Finer as name suggests is the % amount of soil which is
finer than a particular Sieve
%
And its total weight in percentage of
total soil sample weight is cumulative
% retained on this sieve
The amount of soil above this
sieve is coarser
Consider any sieve
from the set .
And the amount of soil below this sieve
is the finer portion of the sample
which has particle size smaller than
openings of this sieve
Total weight of this
portion in percentage
of total soil sample
weight is % Finer
Arithmetically …… % Finer can also be derived
by subtracting Cumulative % retained from 100
Now we Can Complete our Table
Cum % Ret
C1= P1
C2 = P1+P2
C3 = P1+P2+P3
C4 = P1+P2+P3+P4
C5 = P1+P2+P3+P4+P5
Cpan =P1+P2+P3+P4+P5+Ppan
% Finer
100 – C1
100 – C2
100 – C3
100 – C4
100 – C5
100 – C pan
To Understand the
Engineering Behaviour of soil
we employ various methods
Particle Size Distribution is
most important amongst all
To understand engineering behaviour of Soil ,
Particle size distribution is an important test .
As we read earlier learnt
Particle size distribution
Based on their particle
sizes
Is a method of
separation of any soil
sample into different
fractions
X% Y% Z%
There is a little possibility
That the soil
is composed
of all the
particles of
Just one size
In usual situations soil mass consist of
particles of many different sizes
Particle size
may vary
from very
Coarse to
very fine in
just one
sample
A Curve is plotted between % Finer derived from
Sieve analysis & Particle Diameter
Soil Gradation is the classification of Coarse grained soils
Based on different particle sizes contained in the soil mass
Gradation Curve
Is Represented in
TWO ways
Type 1 – Particle size increases from Left to
Right
Type 2 – Particle size Decreases from Left to
Right
Both Curves are used
as per convenience
Whenever we observe the
Grading Curve , we should be
careful about the horizontal
scale of the Graph
Careful
One More thing
to note here is
that
The size of the grains is
plotted on the log scale
Because the range of particle size is
very very large
It will be large to
an extent that ,
It will be very difficult to plot
this range on a NORMAL SCALE
Using Log
scale
We can represent the whole
range of particle size in just
one graph
All the particle range will be in one graph
Let’s see a typical
gradient curve
Each Curve represents a
different soil Gradation
What is the use of it ? Why do we plot these
curve?s
?
Well , By looking at gradation curve we can
estimate many of the soil properties …
We can know the type of soil
Clay Silt Sand Gravel
The position , shape
&Slope of the Curve
Talks about Type Gradation of the soil
Lets Talk about this curve
This Curve Civers a wide range of Particle sizes
If we take any two particle sizes on this graph sacale and try to
determine the amount of soil present in between
You will always get some value No Matter what are these values
This shows that soil graphs represents almost
all the sizes / fractions
This shows that this
particular soil
Graph
Represents a
Soil
Which has almost
all the size of soil
particles present
in it
That is why this curve is said to be representing a well graded soil
Good
Distribution of
Grains
Good Distribution of Grains
Now Lets
take
another
curve
In This curve, there are many
particle sizes, which doesn’t
have representation in the soil
Curve
Absent
Particles
Hence these particles
are not present in the
soil Mass
This Clearly shows that this soil
sample does not have a good
representation of all the particle sizes
Hence This curve is said to be
representing a poorly graded
soil
THEREFORE- A POORLY GRADED SOIL
Either has a Deficiency of certain particle size
OR An excess of Certain Particle sizes OR has
most of the particles of about same size
Same Size particles
All these curves represent a poorly graded
soil
When a soil mass contains Particles
Of About Same Size
We can find it
on the graph
By Taking any two
particle Sizes and
See ……………….
How much part of the soil
is in between these two
Particle sizes
We will notice almost all the part of the soil is between these two particle sizes
These Curves are
steep
And Contain very
short range of
particle Sizes
There is one more
different kind of
curve
In which some of the
particle sizes are
missing In-between
Missing
Particle Sizes
Such soils are
called as ……..
There is a gap in Normal / Well distribution of particles
Such Soils Completely
miss the amount of
soil
Between Two certain
particle sizes
We define a parameter
mathematically to classify
the soil gradation
If it is well graded
or Poorly graded
This Parameter is
called Coeficient
of Uniformity
It is
defined
as
D60 is the diameter , below which
60% of the amount of particles are
finer than this size
And Remaining 40% are coarser
That
means
These
Particles
Make up the 60%
of the Soil
D60 Size Particle
can be any of this
It can be This
particle
And that
says 60% of
the Soil
Is made up of these soil Particles
In other words
60% 0f Soil
Mass
Has Particles
Which all
have Size
Less than this D60 Size
Similarly D10 is
the particle size
For which 10%
of the amount
of soil
Has particles finer than this size
This Particle Size
D10
Is Called
If the value of
Uniformity Co-
efficient
= 1
That means
D60 & D10 are the
Same particles
In that Case , whole
Soil Mass
Consists of only One Grain Size
And Graph of such case Will be something like This
A Vertical Straight Line
And are called Uniformly Graded Soils
There are few values of Uniformity Co-efficient which
have been established for Gradation of Soil
Then Soil is
If
If Then Soil is
But we don’t Rely on
only One Indicator
1
To Classify the soil Gradation
Because in this
Curve below
We can
have
Cu = D60 / D10 = 1.28 / 0.0017 > 6
But It is clear
from the graph
This Soil Misses a
Complete range of Soil
Particle size
So we define
another Co-efficient
This Co-efficicient of Curvature describes the general
shape of Gradation Curve
It is Defined as
D30 is the Particle size
For which 30%
amount of soil
Has
particles
Finer than this size
For a Soil to be
Well Graded
Value of Co-efficient
of Curvature
Must Lie between
1&3
Hence in addition to the
previous establishments
This Criteria must be
followed
In order for a soil
to be well graded
Hence if any of these conditions are not met , Soil is …..
We can get much
information
From the grain size distribution curve
By simply looking at it
We can get to know the Gradation of the soil
Whether the Soil is Well Graded
Or Poorly Graded
Or Gap Graded
Or Uniformly Graded
Secondly , Using
the Curve
We Can differentiate
between
If more than
50% of the soil
Has particle
sizes greater
than 75micron
That Soil is called a
Coarse grained soil
And
similarly
If more than 50%
of the soil material
Has particle size
less than 75
micron
In the
Curve
0.075 mm
Find the particle size
corresponding to 50%
Finer
If the size falls in the
coarse grain category i.e.
greater than 0.075 mm
Then Obviously , More than
50% of the soil material is
Coarse
Hence Soil is Coarse grained
And if this
diameter
Corresponding
to 50% Finer
Falls in fine
grained
category
Then Certainly
more than 50%
of the material
Falls below 0.075 mm
Third- We can
define the type of
Soil by
Curve ,
Shape and
Position
For
example
Curve Shown
below
Falls inside only
the sand zone
Hence this soil is
definitely …….
Now this Curve falls in
Gravel and Sandy zone
So this Soil is Classified as
And this curve Falls
in Silt and clay Zone
Hence this Soil is classified as
We can determine the range of the grain size
distribution of the Soil
And this Curve ,Soil
Contains particles from
this range
And we can
see that this
soil
Does not
contain any
clay content
And with this
particle size
distribution
curve
We can get
% amounts
of
Gravel
Sand
Silt
Clay
Gravels
Sand
Silt
Clay
Thank You – Aman Khullar

Module 4&5 Sieve Analysis & Analysing Gradation Curves.pptx

  • 1.
    Sieve analysis ismethod of Particle size analysis by which we determine amount of particles of different sizes present in a soil sample
  • 2.
    Done for Coarsegrain soils In this method Soil is sieved through a set of sieves >0.075mm or 75 micron Coarse Grained Fraction
  • 3.
    Size of theseopenings give the sieves their name , which is called sieve number Sieves are wired screens having square openings
  • 4.
    A sieve witha mesh opening of 4.75 mm Is designated as 4.75 mm sieve
  • 5.
    Similarly a 600micron sieve refers to a mesh opening of 600 micron or 0.6 mm
  • 6.
    Sieve analysis isdone in 2 ways Dry Sieve Analysis Wet Sieve Analysis
  • 7.
    We take roughly500 gms of soil sample It should not contain any lumps . NO LUMPS
  • 8.
    If it does, then lumps should be pulverized
  • 9.
    We Take itsweight and see this weight as W
  • 10.
    This is sampleis sieved through 4.75 mm sieve .
  • 11.
    Portion of soilwhich is retained on 4.75 mm sieve is called gravel Fraction Portion of soil which pass through the sieve and contain particle size less than 4.75 mm is called Sand Fraction
  • 12.
    Coarse Grain Soilsare divided into 2 categories 1) Gravels having particle/grain size greater than 4.75 mm 2) Sands having particle/ grain size smaller than 4.75 mm Gravels Sand
  • 13.
    Sieves are Wirescreens having square openings
  • 14.
    For Sieve Analysiswe need 2 set of sieves 1) One is for Gravel Fraction 2) One is for Sand Fraction
  • 15.
    Set of CoarseSieves 80mm 40 mm 20 mm 4.75 mm 10 mm
  • 16.
    Set of FineSieves 2 mm 1 mm 600 micron 425 micron 212 micron 150 micron 75 micron 600 micron = 0.6 mm
  • 17.
    The sieves arestacked over one another with increasing size of mesh opening from bottom to top This means that sieve of the smallest opening is kept at bottom Sieve of the largest opening is kept at the top Pan which has no opening is placed below the bottom of the sieve Soil sample is place in the top sieve Lid to cover this arrangement is placed over the top most sieve
  • 18.
    Whole assembly isplaced on a mechanical sieve shaker and shaked for 10 mins
  • 19.
    Amount of soilretained on each sieve is weighed to an accuracy of 0.1 gm W1 W2 W3 W4 W5 W pan
  • 20.
    Then we calculate% of amount of soil retained on each sieve W1 W2 W3 W4 W5 W Pan As weight of Retained soil on each sieve divided by total wait of soil Multiplied by 100 This way we know what % of total weight is retained on a particular sieve • .
  • 21.
    PERCENTAGE WEIGHT RETAINEDON EACH SIEVE W1 W2 W3 W4 W5 W Pan 𝑃 4= 𝑊 4 𝑊 𝑋 100 𝑃 5= 𝑊 5 𝑊 𝑋 100 𝑃 𝑃𝑎𝑛= 𝑊𝑝𝑎𝑛 𝑊 𝑋 100
  • 22.
    For Calculation Purposeand to determine some important characteristics we also calculate two Values
  • 23.
    For Calculation Purposes& to determine some important characteristic of soil sample , we calculate two Values P4 P3 + P 2+ P1+ Cumulative Percentage Retained Let’s write our calculations in a table
  • 24.
    Cumulative % retainedis the total %amount of soil which could not pass a particular sieve
  • 25.
    In other wordsthis % amount of soil has grain size greater than this sieve
  • 26.
    So Let’s Calculatecumulative % retained on every sieve P1 P1 + P2 P1+P2+P3 P1+P2+P3+P4 P1+P2+P3+P4+P5 P1+P2+P3+P4+P5+Ppan
  • 27.
    For Calculation Purpose, in addition to Cumulative % retained , we also calculate
  • 28.
    And we Plota Graph Called as
  • 29.
    % Finer asname suggests is the % amount of soil which is finer than a particular Sieve %
  • 30.
    And its totalweight in percentage of total soil sample weight is cumulative % retained on this sieve The amount of soil above this sieve is coarser Consider any sieve from the set . And the amount of soil below this sieve is the finer portion of the sample which has particle size smaller than openings of this sieve Total weight of this portion in percentage of total soil sample weight is % Finer
  • 31.
    Arithmetically …… %Finer can also be derived by subtracting Cumulative % retained from 100
  • 32.
    Now we CanComplete our Table Cum % Ret C1= P1 C2 = P1+P2 C3 = P1+P2+P3 C4 = P1+P2+P3+P4 C5 = P1+P2+P3+P4+P5 Cpan =P1+P2+P3+P4+P5+Ppan % Finer 100 – C1 100 – C2 100 – C3 100 – C4 100 – C5 100 – C pan
  • 33.
    To Understand the EngineeringBehaviour of soil we employ various methods Particle Size Distribution is most important amongst all
  • 34.
    To understand engineeringbehaviour of Soil , Particle size distribution is an important test . As we read earlier learnt Particle size distribution Based on their particle sizes Is a method of separation of any soil sample into different fractions X% Y% Z%
  • 35.
    There is alittle possibility That the soil is composed of all the particles of Just one size
  • 36.
    In usual situationssoil mass consist of particles of many different sizes Particle size may vary from very Coarse to very fine in just one sample
  • 37.
    A Curve isplotted between % Finer derived from Sieve analysis & Particle Diameter
  • 38.
    Soil Gradation isthe classification of Coarse grained soils Based on different particle sizes contained in the soil mass
  • 39.
  • 40.
    Type 1 –Particle size increases from Left to Right
  • 41.
    Type 2 –Particle size Decreases from Left to Right
  • 42.
    Both Curves areused as per convenience Whenever we observe the Grading Curve , we should be careful about the horizontal scale of the Graph Careful
  • 43.
    One More thing tonote here is that The size of the grains is plotted on the log scale
  • 44.
    Because the rangeof particle size is very very large
  • 45.
    It will belarge to an extent that , It will be very difficult to plot this range on a NORMAL SCALE
  • 46.
    Using Log scale We canrepresent the whole range of particle size in just one graph
  • 47.
    All the particlerange will be in one graph
  • 48.
    Let’s see atypical gradient curve Each Curve represents a different soil Gradation
  • 50.
    What is theuse of it ? Why do we plot these curve?s ?
  • 51.
    Well , Bylooking at gradation curve we can estimate many of the soil properties …
  • 52.
    We can knowthe type of soil Clay Silt Sand Gravel
  • 53.
    The position ,shape &Slope of the Curve Talks about Type Gradation of the soil
  • 54.
    Lets Talk aboutthis curve This Curve Civers a wide range of Particle sizes
  • 55.
    If we takeany two particle sizes on this graph sacale and try to determine the amount of soil present in between You will always get some value No Matter what are these values
  • 56.
    This shows thatsoil graphs represents almost all the sizes / fractions
  • 57.
    This shows thatthis particular soil Graph Represents a Soil Which has almost all the size of soil particles present in it
  • 58.
    That is whythis curve is said to be representing a well graded soil Good Distribution of Grains Good Distribution of Grains
  • 59.
    Now Lets take another curve In Thiscurve, there are many particle sizes, which doesn’t have representation in the soil Curve Absent Particles Hence these particles are not present in the soil Mass
  • 60.
    This Clearly showsthat this soil sample does not have a good representation of all the particle sizes Hence This curve is said to be representing a poorly graded soil
  • 61.
    THEREFORE- A POORLYGRADED SOIL Either has a Deficiency of certain particle size OR An excess of Certain Particle sizes OR has most of the particles of about same size Same Size particles
  • 62.
    All these curvesrepresent a poorly graded soil
  • 63.
    When a soilmass contains Particles Of About Same Size
  • 64.
    We can findit on the graph By Taking any two particle Sizes and See ………………. How much part of the soil is in between these two Particle sizes We will notice almost all the part of the soil is between these two particle sizes
  • 65.
    These Curves are steep AndContain very short range of particle Sizes
  • 66.
    There is onemore different kind of curve In which some of the particle sizes are missing In-between Missing Particle Sizes Such soils are called as ……..
  • 67.
    There is agap in Normal / Well distribution of particles
  • 68.
    Such Soils Completely missthe amount of soil Between Two certain particle sizes
  • 69.
    We define aparameter mathematically to classify the soil gradation If it is well graded or Poorly graded
  • 70.
    This Parameter is calledCoeficient of Uniformity It is defined as D60 is the diameter , below which 60% of the amount of particles are finer than this size And Remaining 40% are coarser
  • 71.
  • 72.
    D60 Size Particle canbe any of this It can be This particle And that says 60% of the Soil Is made up of these soil Particles
  • 73.
    In other words 60%0f Soil Mass Has Particles Which all have Size Less than this D60 Size
  • 74.
    Similarly D10 is theparticle size For which 10% of the amount of soil Has particles finer than this size
  • 75.
  • 76.
    If the valueof Uniformity Co- efficient = 1 That means D60 & D10 are the Same particles
  • 77.
    In that Case, whole Soil Mass Consists of only One Grain Size
  • 78.
    And Graph ofsuch case Will be something like This A Vertical Straight Line
  • 79.
    And are calledUniformly Graded Soils
  • 80.
    There are fewvalues of Uniformity Co-efficient which have been established for Gradation of Soil Then Soil is If If Then Soil is
  • 81.
    But we don’tRely on only One Indicator 1 To Classify the soil Gradation
  • 82.
    Because in this Curvebelow We can have Cu = D60 / D10 = 1.28 / 0.0017 > 6
  • 83.
    But It isclear from the graph This Soil Misses a Complete range of Soil Particle size So we define another Co-efficient
  • 84.
    This Co-efficicient ofCurvature describes the general shape of Gradation Curve
  • 85.
  • 86.
    D30 is theParticle size For which 30% amount of soil Has particles Finer than this size
  • 87.
    For a Soilto be Well Graded Value of Co-efficient of Curvature Must Lie between 1&3
  • 88.
    Hence in additionto the previous establishments This Criteria must be followed In order for a soil to be well graded
  • 89.
    Hence if anyof these conditions are not met , Soil is …..
  • 90.
    We can getmuch information From the grain size distribution curve By simply looking at it
  • 91.
    We can getto know the Gradation of the soil
  • 92.
    Whether the Soilis Well Graded
  • 93.
  • 94.
  • 95.
  • 96.
    Secondly , Using theCurve We Can differentiate between
  • 97.
    If more than 50%of the soil Has particle sizes greater than 75micron That Soil is called a Coarse grained soil
  • 98.
    And similarly If more than50% of the soil material Has particle size less than 75 micron
  • 99.
    In the Curve 0.075 mm Findthe particle size corresponding to 50% Finer If the size falls in the coarse grain category i.e. greater than 0.075 mm
  • 100.
    Then Obviously ,More than 50% of the soil material is Coarse Hence Soil is Coarse grained
  • 101.
    And if this diameter Corresponding to50% Finer Falls in fine grained category Then Certainly more than 50% of the material Falls below 0.075 mm
  • 102.
    Third- We can definethe type of Soil by Curve , Shape and Position
  • 103.
    For example Curve Shown below Falls insideonly the sand zone Hence this soil is definitely …….
  • 104.
    Now this Curvefalls in Gravel and Sandy zone So this Soil is Classified as
  • 105.
    And this curveFalls in Silt and clay Zone Hence this Soil is classified as
  • 106.
    We can determinethe range of the grain size distribution of the Soil
  • 107.
    And this Curve,Soil Contains particles from this range And we can see that this soil Does not contain any clay content
  • 108.
    And with this particlesize distribution curve We can get % amounts of Gravel Sand Silt Clay Gravels Sand Silt Clay
  • 109.
    Thank You –Aman Khullar