Ex No: 1 GRAIN SIZE DISTRIBUTION – SIEVE ANALYSIS METHOD Date: Aim: To determine the distribution of coarse grain size larger than 75 microns of a soil and to classify the given coarse grained soil. Apparatus Required: Mechanical sieve shaker, Set of IS Sieves, Balance accurate to 0.1g, Sieve brusher, and Soil sample. Formula: (i) Percentage retained on any sieve = (Weight of soil retained/Total soil weight) x 100% (ii) Cumulative percentage retained on any sieve = Sum of percentages retained on all coarser sieves (iii) Percentage finer than any other sieve size = (100 - cumulative percentage retained on that sieve) Data Representation: The grain size distribution of a soil is presented as a curve on a semi-logarithmic plot, the ordinate being the percentage finer than any other sieve size whereas the particle size is represented on a logarithmic scale in abscissa. The general slope and shape of the distribution curve can be described by means of coefficient of 1
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Ex No: 1 GRAIN SIZE DISTRIBUTION – SIEVE ANALYSIS METHODDate:
Aim:
To determine the distribution of coarse grain size larger than 75 microns of a soil and
to classify the given coarse grained soil.
Apparatus Required:
Mechanical sieve shaker, Set of IS Sieves, Balance accurate to 0.1g, Sieve brusher,
and Soil sample.
Formula:
(i) Percentage retained on any sieve = (Weight of soil retained/Total soil weight) x 100%
(ii) Cumulative percentage retained on any sieve = Sum of percentages retained on all coarser sieves
(iii) Percentage finer than any other sieve size = (100 - cumulative percentage retained on that sieve)
Data Representation:
The grain size distribution of a soil is presented as a curve on a semi-logarithmic plot, the
ordinate being the percentage finer than any other sieve size whereas the particle size is
represented on a logarithmic scale in abscissa.
The general slope and shape of the distribution curve can be described by
means of coefficient of uniformity (Cu ) and the coefficient of curvature (Cc) defined as
follows.
Cu = D60 / D10
Cc = D30 2
D60 X D10
The particle size such that 10% of the particles are smaller than that size is denoted by D10
Size D10 is defined as the “effective size”. Other sizes such as D30 and D60 can be defined in a
similar way.
Tabulation:
1
Weight of soil sample taken for analysis =
IS Sieve designation
in mm.
Weight of soil retained
in (g).
Percentage retained in
%
Cumulative percent
retained in %
Percent finer in %.
2
Procedure:
1) Take the 200-300g of oven dry soil as a representative sample from a bag of material.
2) Place the IS Sieve in order (i.e.) starting from 4.75mm to 75 microns at the bottom.
3) The weighed oven dried sample is placed on 4.75mm sieve. Then the sieving should
continue for at least 10 minutes in a mechanical sieve shaker.
4) The sample retained in each sieve should be weighed. The percentage retained on
each sieve is computed by dividing the weight retained on each sieve by the original
sample weight.
5) Then the percent finer is computed by starting with 100 percent and subtracting the
percent retained on each sieve as cumulative procedure.
6) The coefficient of uniformity and coefficient of curvature is calculated using the
formula.
Result:
Effective size, D10 (mm) =
Uniformity coefficient Cu =
Curvature coefficient Cc =
Gravel = %
Sand = %
Coarse sand = %
Medium sand = %
Fine sand = %
Silt and clay = %
3
4
Ex No: 2 GRAIN SIZE DISTRIBUTION – HYDROMETER
Date: ANALYSIS METHOD
Aim:
To determine the grain size distribution of the given soil sample with significant
fraction passing through 75micron sieve and its classification.
Rc =hydrometer reading corrected for meniscus, dispersing agent and temperature.
Corrections applied to Hydrometer test
1. Meniscus correction (Cm) =
2. Dispersing agent correction (Cd) =
3. Temperature Correction (Ct)
The hydrometer is usually calibrated to measure the specific gravity of a fluid at a particular calibration temperature, normally 20▫c. For other temperatures, a correction is required and this may be computed from
Ct = (( Gwc-Gwt)] * av (Tc))103
Gwc = Specific gravity of water at calibration temperature
Gwt = Specific gravity of temperature of test
Zr = Volume coefficient of expansion of glass
5
Tabulation:
Hydrometer No =
Weight of dry soil taken for analysis, Ws =
Specific gravity of soil solids, Gs =
Dispersing agent correction, Cd =
Meniscus correction, Cm =
Elapsed time in
min
Temp in °C
Hydrometer reading R’h
Meniscus correction Rh=R’h
+ Cm
Temperature correction
Ct
Combined correction
C=Cm+Cd+Ct
Corrected hydrometer
ReadingRc= R’h +C
ZrDiameter
D N%
½
1
2
4
8
15
30
60
120
240
480
1440
Procedure:
6
Calibration of hydrometer
Volume of hydrometer
1) Immerse the hydrometer in partially filled measuring cylinder and note down the
displacement of water, which is equal to the volume of the hydrometer in milliliters
(ml).
2) Area of the cross section of the measurement cylinder measuring the distance in cm,
between two graduation on the cylinder area of cross section then equal to the volume
included between two graduation divided by the distance between them.
3) Keep the hydrometer on the white paper. Draw its boundaries and mark the major
calibration and mark it on the paper.
4) Measure the height of the bulb from the neck to the bottom of the bulb.
5) Measure the height (H) between the neck and each major calibration mark (Rh).
6) Record the values of H Vs Rh table and calculate the effective depth of the
corresponding to each of the major calibration mark Rh.
Hc = H + (L/2) x (h – (Vh/2))
7) Draw the calibration curve Hv and Rh.
Sedimentation Test:
1) Prepare 1000ml of soil suspension as explained earlier. Mix the soil with water
completely by turning the jar upside down and place it on the table. Start the
stopwatch.
2) Remove the hydrometer from the jar and rinse it with the water and then again float it
in compression jar containing water with dispersing agent to some concentration as in
soil substance.
3) Again immerse the hydrometer in the soil suspension and the readings (Rh) after 0.5,1,
2,4,8,15,30,60,1440 minutes are recorded from the beginning of sedimentation. Take
the hydrometer out after every reading.
Result:
Thus the distribution of particle size finer than 75µ sieve is found by sedimentation
analysis using hydrometer, and then the graph is plotted between the grain size and the %
finer.
% of silt =
% of clay =
7
Ex No: 3 SPECIFIC GRAVITY OF A SOILDate:
8
Aim:
To determine the specific gravity of a soil by using Pycnometer.
Apparatus required:
1. Pycnometer
2. Soil Sample
3. Weighing Balance
4. Oven
5. 4.75mm IS sieve
Formula Used:
The specific gravity of the given soil can be calculated from the formula,
(W2 – W1) Gs(at t▫c) =
(W4 -W1) – (W3 – W2)
Where,
G - Specific gravity of the soil
W1 - Weight of empty pycnometer
W2 - Weight of pycnometer + Soil
W3 - Weight of pycnometer + Soil + Water
W4 - Weight of pycnometer + Water.
Correction To temperature:
The specific gravity of given soil at standard temperature 27◦c is computed as αGs
α =
9
where α is the ratio of the unit weight of water at the temperature t◦c of the test and at
27◦c
Tabulation:
Test No. 1 2 3
Temperature ◦ C
Weight of pycnometer (kg)
Weight of pycnometer + Soil (kg)Weight of pycnometer + Soil + Water(kg)Weight of pycnometer + Water(kg)Specific gravity of soil at t0 CSpecific gravity of soil at standard temperature 270 C
10
Procedure:
1) To clean and dry the pycnometer, wash it thoroughly with distilled water and
allow it to drain.
2) Rinse the bottle with alcohol to remove water and drain the alcohol.
3) Then rinse the bottle with ether to remove alcohol and drain the ether by turning
the bottle upside down for few minutes.
4) Find the empty weight of the pycnometer (W1).
5) Take some known quantity of oven-dried sand and transfer it carefully into the
pycnometer. Now measure the weight of the empty container with the soil sample
(W2).
6) Then pour required amount of distilled water so that it fills up to the brim. Now
again it is weighed (W3).
7) Now remove all the soil particles and wash the pycnometer and rinse it with
distilled water. Then fill the pycnometer with distilled water completely and then
it is weighed (W4).
Result:
The average specific gravity of soil sample at 27° C =
11
12
Ex no: 4 RELATIVE DENSITY OF SANDDate:
Aim:
To determine the relative density of given soil
Apparatus required:
1. Relative density apparatus
2. Mould
3. Dead load
4. Sleeve
5. Dial gauge
Formula:
Relative density Rd = X 100Where,
γf - Dry unit weight of sand in the field (Kg /cm3 )
γ 2 - Dry unit weight of sand in the densest form (Kg /cm3 )
γ1 - Dry unit weight of sand in the loosest form (Kg /cm3 )
13
Observation
Diameter of the mould (d) =
Height of the mould (h) =
Unit weight of sand in looser state:
Volume of mould (Vc =πd2h/4)
Volume of sand in mould as looser state (Vl)
Dry Weight of sand in mould (Ws)
Dry Unit weight sand at looser state (γmin)
=
Unit weight of sand in denser state:
Dry Weight of sand in mould (Ws)
Volume of sand at denser state (Vd)
Vd= , h1==reduced ht .
Dry Unit weight of sand in denser state (γmax)
14
Procedure:
1. A known weight of sample is taken. The sample is then pulverized and sieved
through the required sieve.
2. The minimum dry unit weight is found by pouring the dry soil in the mould using
poring device. The spout of the pouring device is so adjusted that the height of free
fall is always 25mm. The mass and volume of the soil deposited are found. The ratio
of Mass and volume of the soil deposit yields minimum dry weight of the soil in a
loose condition.
3. The maximum dry unit weight is also determined by dry method. In the dry method,
the mould is filled with thoroughly with mixed oven-dry soil. A surcharge is placed
on the soil surface, and the mould is fixed to the vibrator deck. The specimen is
vibrated for 8 minutes. The mass and volume of the soil in the compacted sand are
found. The ratio between maximum mass of the dry soil to the volume yields
maximum dry unit weight.
4. The unit weight of in-situ deposit is found out from three laboratory procedures such
as sand replacement method, specific gravity test and oven drying method.
Result:
The relative density of given soil sample is found to be =
15
16
Ex No: 5 ATTERBERG’S LIMITDate:
Aim:
To Classify the given fine grained soil based on its plasticity characteristics.