Just a simple aid for Practicals lab of soil mechanics of different soil test.

1. Table of Contents
1. Determination of water content by..................................................................................................3
Ovendry method.............................................................................................................................3
Theory:......................................................................................................................................3
Procedure:..................................................................................................................................3
Observations and Calculations:....................................................................................................4
Psycnometer test to find water content...........................................................................................7
Theory:.......................................................................................................................................7
Procedure:..................................................................................................................................8
2. Specific gravity of solids.................................................................................................................10
Pycnometer method.....................................................................................................................12
density bottle method...................................................................................................................13
3. Dry density of soil .........................................................................................................................15
Core cutter method ......................................................................................................................15
4. Particle size analysis......................................................................................................................17
Sieve Analysis...............................................................................................................................17
Purpose:...................................................................................................................................19
5. Liquid limitProcedure...................................................................................................................20
Plastic limit.......................................................................................................................................23
Theory .........................................................................................................................................23
Procedure ....................................................................................................................................23
SedimentationAnalysis.................................................................................................................27
7. Modified Compaction test ............................................................................................................28
8. Permeability.................................................................................................................................37
General........................................................................................................................................37
Procedure ....................................................................................................................................39
Calculation ...................................................................................................................................39
External analysis........................................................................................................................40
CONSTANT HEAD PERMEABILITY TEST ...............................................................................................41
Equipments:-................................................................................................................................41

2. Procedure ....................................................................................................................................42
Calculations ..............................................................................................................................43
FALLING HEAD PERMEABILITY TEST ...................................................................................................43
Test Procedure:-...........................................................................................................................44
9. Consolidation test.........................................................................................................................45
Procedure ....................................................................................................................................47
10. California Bearing Ratio ( CBR) of soil............................................................................................52
General........................................................................................................................................52
CBR Test revalance....................................................................................................................53
Soaking.....................................................................................................................................56
Penetration test...............................................................................................................................57
Observation..................................................................................................................................58
Penetration Result.....................................................................................................................59
Results......................................................................................................................................60

3. 1. Determinationofwater content by
Ovendry method
Theory:
The water content (w) of a soil sample is equal to the mass of water divided
by the mass of solids.
Where M1=mass of empty container with lid,
M2= mass of the container with wet soil and lid
M3= mass of the container with dry soil and lid.
Equipment:
1. Thermostatically controlled oven, maintained at a temperature of 1100
±
50
C.
2. Weighing balance with accuracy of 0.04% of the mass of the soil taken
3. Desiccator, with any suitable desiccating agent
4. Airtight container made of non-corrodible material with lid
5. Tongs
Soil Specimen:
The soil specimen should be representative of the soil mass. The quantity of
the specimen taken would depend upon the gradation and the maximum
size of the particles. For more than 90% of the particles passing through 425
micron IS sieve, the minimum quantity is 25g.
Procedure:
1. Clean the container, dry it and weight it with lid (M1).
2. Take the required quantity of the wet specimen in the container and close
it with lid. Take the mass (M2)

4. 3. Place the container with its lid removed in the oven till mass becomes
constant (normally for 24 hours).
4. When the soil has dried, remove the container from the oven using tongs.
Replace the lid on the container. Cool it in a desiccator.
5. Find the mass (M3) of the container with lid and dry soil sample.
Observations andCalculations:
Data sheet for water content by oven-drying method
Sl. No. Observations an Calculations
Determination No.
1 2 3
Observation
1 Container No.
2 Mass of empty container (M1)
3 Mass of container + soil (M2)
4 Mass of container + dry soil (M3)
Calculations
5
Mass of water Mw= M2 – M3
6
Mass of solids, Ms= M3 – M1
7
Water content= (5)/(6)x100


7. Psycnometer test to find water content
Theory:
A Pycnometer is a glass jar of about 1 liter capacity, fitted with a brass
conical cap by means of a screw type cover. The cap has a small hole of
about 6mm diameter at its apex.
The water content (w) of the sample is obtained as
Where M1=mass of empty Pycnometer,
M2= mass of the Pycnometer with wet soil
M3= mass of the Pycnometer and soil, filled with water,
M4 = mass of Pycnometer filled with water only.
G= Specific gravity of solids.

8. Procedure:
1. Wash and clean Pycnometer and dry it.
2. Determine the mass of Pycnometer with brass cap and washer (M1)
accurate to 1.0g.
3. Place about 200 to 400g of wet soil specimen in the Pycnometer wand
weigh it with its cap and washer (M2).
4. Fill water in the Pycnometer containing the wet soil specimen to about
half its height.
5. Mix the contents thoroughly with a glass road. Add more water and stir it.
Fill the Pycnometer with water, flush with the hole in the conical cap.
6. Dry the Pycnometer from outside and take its mass (M3).
7. Empty the Pycnometer. Clean it thoroughly. Fill it with water, flush with
the hole in the conical cap and weigh (M4)
Data sheet for water content by Pycnometer method
Sl. No. Observations an Calculations
Determination No.
1 2 3
Observation
1 Mass of empty pycnometer (M1)
2 Mass of pycnometer + wet soil (M2)
3
Mass of Pycnometer soil, filled with
water (M3)
4
Mass of Pycnometer filled with water
only (M4)
Calculations
5
M2 – M1
6
M3 – M4

9. 7
(G – 1) / G
8
w (using above formula)

10. 2. Specific gravity ofsolids
• Knowledgeof the specificgravityof soilsisrequiredforthe determinationof voidsratio,degree
of saturation,andinthe sedimentationandconsolidationtests.
• The individual mineral particlesconstitutingasoil have differentspecificgravities.
• The specificgravitycanbe determinedeitherbythe use of a 50 - 100ml densitybottle,a500ml
flaskor a pycnometer.
• Densitybottle methodisthe usual laboratorymethod.

12. Pycnometer method
1. Cleananddry the pycnometer .Finditsmasswithcap as W1.

13. 2. Place about200 gm of ovendriedsoil passingthrough4.75 mm sieve.
3. Determine massof pycnometer withdrysoil asW2.
4. Addsufficientamountof de-airedwatertothe soil inthe pycnometer.Thoroughlymix it.
Determine massof pycnometer withsoil andwaterasW3.
5. Emptythe pycnometer,cleanitandwipe itdry.
6. Fill the pycnometer withdistilledwaterandfinditsmassas W4.
7. Now,calculate the specificgravityof soil solidsasunder:
G=[(W2-W1)/{(W2-W1)- (W3-W4)}]
density bottle method
A densitybottle of 50ml capacityis used.Bottle isdriedandcleanedattemperature of 105 -110o
C.
Mass of bottle includingstopperistaken.About5-10gof soil istakeninthe bottle andweighted.
Distilledwaterisaddedtocoversample.The soil isallowedtosoakwaterforabout2 hours.Air
entrappedisexpelledbyapplyingavacuum pressure of 55 cm of mercury.The stopperisinsertedin
bottle andmass istaken. The bottle isemptied,washedandrefilledwithdistilledwater.The massof
bottle filledwithwateristaken.
Let W1= massof emptycontainer
W2= massof container+ dry soil
W3= massof container+ wetsoil
W4=mass of bottle filledwithwater

14. G=[(W2-W1)/{(W2-W1)- (W3-W4)}]

15. 3. Dry density of soil
Core cutter method
• A core cutter isa steel cylinderopenatbothendswithone endsharpenedtoformthe cutting
edge.
• The usual dimensionsare 10cm internal diameterandheightabout12 to 15 cm
• The internal diameter,heightandmassof core-cutterare noted.
• The place where the fielddensityistobe determinedisclearedof shrubs,if any,levelledand
the core-cutterisplacedverticallyonthe groundsurface
• A steel ringabout2.5cm height(Steel Dolly) isplacedontopof the core cutterand is gently
drivenintothe groundbyblowsof a rammer,until the topof the steel ringisnearlyflushwith
the groundsurface.
• Sufficientsoil isexcavatedfromaroundthe core-cuttertoenable apersontoput hishandsand
liftthe core-cutterwithsoil inside off the ground.
• The core cutter withsoil insideisbroughttothe laboratory,the endsare trimmed,levelledand
weighed.
• The soil isremovedfromthe core-cutterandthe samplesare takenfromtop, middle and
bottompositionsforwatercontentdetermination.
• The average of the three determinationsgivesthe in-situ watercontent
1. Measure the inside dimensionsof the core cutter
2. Determine emptyweightof core cutter( W1)
3. Level the surface,about300 mm square inarea.
3. Place the dollyoverthe topof the core cutterand pressthe core cutterintothe soil massusing
the rammer.
4. Stopthe processof pressingwhenabout15 mm of the dollyprotrudesabove the soil surface.
5. Remove the soil surroundingthe core cutterand take out the core cutter.
6. Remove the dolly.Trimthe top andbottomsurface of the core cuttercarefullyusingastraight
edge.
7. Weightthe core cutter filledwiththe soil(W2).
8. Remove the core of the soil fromthe cutter.Determine the watercontent

17. 4. Particle size analysis
Particle size analysisis amethodof separationof soilsintodifferentfractionsbasedonparticle size.
Particle analysisisdone in2stages:-
Sieve Analysis
PROCEDURE
a) The test sample isdriedtoa constantweightat a temperature of 110 + 5o
C and weighed.
b) The sample is sievedbyusingasetof IS Sieves.
c) On completionof sieving,the material oneachsieve isweighed.
d) Cumulative weightpassingthrougheachsieve iscalculatedasa percentage of the total sample
weight.
Finenessmodulusisobtainedbyaddingcumulative percentage of aggregatesretainedoneachsieve
and dividingthe sumby100

18.  The consistencyof a fine grainedsoil isthe physical state inwhichitexists.
 The water contentat whichthe soil changesfromone state to otherare knownasconsistency
limitsorATTERBERG limits.
 At the same watercontentone soil maybe relativelysoft,whereasanothersoil maybe hard.

19.  Thus consistencylimitsare veryimportantpropertiesof finegrainedsoil.
Purpose:
 Thisis performedtodetermine the plasticandliquidlimitsof afine grainedsoil.The Atterberg
limitsare basedonthe moisture contentof the soil.
 The plastic limit:isthe moisture contentthatdefineswhere the soil changesfromasemi-solid
to a plastic(flexible)state.
 The liquidlimit:isthe moisture contentthatdefineswherethe soil changesfromaplastictoa
viscousfluidstate.

20. 5. Liquid limit Procedure
1) The liquidlimitdevice isadjustedtohave a free fall of cupof 1cm thisis done withthe helpof
adjustingscrewprovidednearthe cuphinge.
2) Take 100gm of soil sample afterpassingfrom425µ ISsieve.
3) Add15% waterinsoil by weightof soil.
4) Mix itthoroughlytomake uniformpaste.
5) Put wetsoil incup andleveleditatlowestspotandsqueezeddownwithspatulatohave a
uniformspace.
6) Thenwiththe helpof casegrande’stool ,divided intotwopartsbygroovingup to bottom
surface of cup.
7) Rotate handle at the rate of 2 no.per secondand cup will startprocessof up and down.
8) Countthe rotationof handle until the bottomsurface of groove isconnected.
9) Thenadd wateras 3% of soil and mix thoroughlyandrepeatprocess.
10) The processof addingwateriscontaineduntil connectingof groove iscompletelyin25 blows.
11) Thenget the resultof Liquidlimit.
12) Water contentisplottedagainstlogof blows.
13) Beststraightline fittingthe pointsdrawn.
14) Moisture contentat 25 blowisthe LiquidLimitof the soil.

23. Plastic limit
Theory
• Sample of soil ismixedwithdistilledwateruntil itissufficientlyplastictobe rolledintoaball
betweenpalmsof hands.
• A small portionof the ball isthenrolledona smoothplate intoa threadof 3mm diameter,and
the threadis lookedforsignsof cracking.
• If no cracks are seen,the threadispickedupand againrolledintoa ball betweenpalms.
• The water contentisreducedbythe heatof the fingers.
• The ball is thenrolledonsmoothplate intoathreat of 3mm diameter.
• The stepsare repeateduntil a3mm diameterthreatfirstshowssignsof cracking.
• A portionof the threatis takenfor watercontentdeterminationwhichgivesthe plasticlimit.
Procedure
 The minimumwatercontentatwhicha soil will justbegintocrumble whenitisrolledintoa
threadof approximately3mmin diameter.
 Whenpointisreachedwhere threadiscrackingand cannot be re-rolledto3 mmdiameter,
collectat least6 grams and measure watercontent.
 The test isrepeatedtakingafreshsample eachtime.Plasticlimitistakenasaverage of three
values.

27. Sedimentation Analysis
The firstanalysisismeantforcoarse grainedsoil (particle size >75 micron).Whereas sedimentation
analysisisforfine grainedsoils.( particle size<75 micron).
Particle size smallerthan0.2 microncan be determinedbyanelectronmicroscope orbyX-ray
technique.

28. 7. ModifiedCompactiontest

37. 8. Permeability
General
Permeabilityisa soil property indicatingthe ease with which water will flowthrough the soil.
Permeabilitydependson the followingfactors:
1) the size of soil grains
2) the propertiesof pore fluids
3) the void ratio of the soil
4) the shapesand arrangementof pores
5) the degree ofsaturation
There are fourlaboratorymethodstypicallyusedformeasuringthe permeabilitycoefficient:
1) the variable-head(falling-head) test
2) the constant-headtest
3) the capillarymethod
4) back calculationfromthe consolidationtest
Generally,soilswhichcontain10%or more particlespassingthe No.200 sieve are testedusingthe
falling-head method. The constant-headmethodislimitedto disturbedgranular soilscontainingnot
more than 10% passing the No.200 sieve.
The constant head test methodis usedfor permeable soils(k>10-4
cm/s), and the fallingheadtestis
mainlyusedforlesspermeable soils(k<10-4
cm/s).

39. Procedure
1. Usingthe relative densitiesgivenbyTA (32,34,36) determinethe densityof the specimen, γ
2. Measure the diameterandlengthof specimenmold,calculate the volume,V.Then,determine
the weightof the sample neededatthe particularrelativedensity,W
3. Set upthe permeameter
a. . Loosenthe lowerhose clamponthe topcouplingandremove the reservoirtube.
b. Place testsample inthe mold,levelwithastraightedge,place inthe bucket
c. Measure the diameterof boththe reservoirtube andbubble tube,lengthof mold,L.
d. Measure the distance betweenthe topof the moldand topof bucket,H1
e.Take the moldout of the bucket,place the reservoirtube backonthe moldandtightenthe
clamps
f.Measure the distance fromthe bottomof the bubble tube tothe topof the mold,H2; the
waterheaddifference willbe H2-H1
g. Place permeametersinthe bucketandfill slowlyallowingwatertosaturate the sample from
the bottomup
h. Whenwateroverflows,openthe upperandlowerportstoallow waterinthe reservoirtube,
keepthe wateroverflowingthe bucket
i.Seal the top of the bubble tube,use vacuum, draw the waterintothe bubble tube sothatthe
waterlevel isbetween20and 25cm highas markedon the reservoirtube.Close the portswith
clamps.Note the mark at whichitstarts
j. Openthe bubble tube andstartthe timer,endtestwhenthe waterlevel dropstothe bottom
of the bubble tube,orstopafterbetween15and 30 minutes.
Calculation
 Dry density
γd= (γdmax *γdmin ) / [Dr*(γdmax –γdmin) –γdmax
Where γdmax=108.5 pcf, γdmin=90.3 pcf, Dr=32, 34, 36, respectively

40.  Sample Weight
W=Volume * γd
 Water Head
H=H1-H2
 Gradient
i=H/L
 Flow
Q=(Hstart-Hfinish)*A
Where A=area of reservoirtube - areaof bubble tube
 Hydraulic conductivityor permeability
k=flow/(iAt)
External analysis
(1) Take temperature intoconsideration:
KT =Q/iA
(2) The viscosityof the waterchangeswithtemperature.Astemperature increasesviscositydecreases
and the permeabilityincreases.The coefficientof permeabilityisstandardizedat20°C,and the
permeabilityatanytemperature TisrelatedtoK20 bythe followingratio:
K20=KTηT/ η20
Where:
η20 and ηT are the viscositiesatthe temperature 20and T, respectively,andcanbe foundfromtables;

41. CONSTANTHEAD PERMEABILITYTEST
Equipments:-
 Permeabilitymould,internal diameter=100mm, effectiveheight=127.3mm, capacity=
1000ml, complete withall accessories
 Constantheadtank.
 Graduatedcylinder,stopwater,thermometer.
 Filterpaper,vacuumpump.
 Weightingbalance,0.1gm accuracy.

42. Procedure
1. Measure internal dimensionsof the mould.Applyalittlegrease onthe inside tothe mould.
2. Take about 2.5kg of the soil,froma thoroughlymixedwetsoil,inthe mould.Compactthe soil at
the requireddrydensityusingasuitable compactingdevice.
3. Remove the collarandbase plate.Trimthe excesssoil levelwiththe topof the mould.
4. Cleanthe outside of the mould.Findthe massof the soil inthe mould.Take a small specimenof
the soil incontainerforthe water constantdetermination.
5. Saturate the porousstones.
6. Place the porousstone (disc) onthe drainage base andkeepa filterpaperonthe porousstone.
7. Place the mouldwithsoil onthe drainage base.
8. Place a filterpaperanda porousstone on the top of specimen.
9. Connectthe constantheadtank to the drainage cap inlet.
10. Openthe stop cock, andallowthe waterdownwardsothat all the air is removed,thenclose
the stop cock.
11. Now,againopenthe stopcock andat the same time start the stopwatch.Collectthe water
flowingoutof the base ina measuring flaskforsome convenienttime interval.

43. 12. Measure the difference of head(h) inlevelsbetweenthe constantheadtank and the outletin
the base
Calculations
• c/s area of specimen= A = (π/4) x D2
(cm2
)
• Volume of mould = V = (π/4) x D2
x L (cm3
)
• Mass of wetsoil inthe mould= M= M2 – M1
Where,M1 = massof emptymould.
M2 = mass of mould+ wetsoil
• Bulkdensityof soil, = _____ gm/cm3
• Dry densityof soil, = _____ gm/cm3
Results:-
The coefficientof permeabilityof agivensoil sample is…………cm/sec
FALLING HEAD PERMEABILITYTEST

44. Test Procedure:-
1. Prepare the remouldedsoil specimeninthe permeameterandsaturate it.
2. Keepthe permeametermouldinthe bottom tankandfill the bottomtank withwaterup toits
outlet.
3. Connectthe waterinletnozzle of the mouldtothe standpipe filledwith water.Permitwater
to flowforsome time till steadystate of flow isreached.
4. Nowopenthe valve of standpipe andrecord the time (t) to fall the headfromh1 to h2. Repeat
thisstepat leasttwice.
Normally,
 Constantheadpermeabilitytestisusedformore permeable soilslikesand.
 Fallingheadpermeabilitytestisusedfor lesspermeable soilslikeclay.

45. 9. Consolidationtest
ConsolidationTest
Two typesof consolidometers(oedometers)commonlyused:
Floating-ring
Fixedring
Thislab usesthe fixed-ringconsolidometer
ASTMD 2435

47. Procedure
Measure the inner diameter and height of the consolidation cutter/ring and record its
mass
Prepare a soil specimen for the test by trimming and placing the soil in the ring
Determine the mass of ring + soil
Collect some excess soil for moisture content
Assume Gs = 2.7
Saturate the lower (larger) porous stone on the base of the consolidometer
Place the specimen and ring and place the upper stone/disk Follow the rest in your lab
manual
Place 1.5 kg (1st day), 3kg (2nd day), 6kg (3rd day), 12kg (4th day)

52. 10. CaliforniaBearing Ratio ( CBR) ofsoil
General
California bearingratio (CBR) is a penetrationtest forevaluationof the mechanical strengthof road
subgradesand basecourses
I The California Bearing Ratio devised by engineers of the
California Division of Highways in nine years period to 1938.
I The California bearing ratio (CBR) is a penetration test for
evaluation of the mechanical strength of road subgrades
and base courses .
I The test is performed by measuring the pressure required
to penetrate a soil sample with a plunger of standard area .
I The measured pressure is then divided by the pressure required
to achieve an equal penetration on a standard crushed
rock material .

53. CBRTestrevalance
It is used for the evaluation of sub-grade strength of roads
and pavements.
I The results obtained by these tests are used with the empirical
curves to determine the thickness of pavement and
its componentlayers.
I CBR-value is used as an index of soil strength and bearing
capacity.
I Indian Roads Congress (IRC)has standardized the guidelines
for the designof flexible pavements based on CBR test
(IRC: 37-2001).
I The CBR test can be conducted forboth sub-grade soil and
Granular sub-base material.

55. Sample Preparation
Undisturbed specimen
Samples are obtained from the file soil by cutting mould. Remoulded
Specimen
I Prepare the remoulded specimenat Proctor’s maximum dry
density or any other density at which C.B.R> is required.
I Maintain the specimenat optimum moisture content or the
field moisture as required.
I The material used should pass 20 mm I.S. sieve but it should
be retained on 4.75 mm I.S. sieve.
I Prepare the specimeneither by dynamic compactionor by
static compaction.
DynamicCompaction
I Take about 4.5 to 5.5 kg of soil and mix thoroughly with the
required water.
I Fix the extension collar and the base plate to the mould.
Insert the spacerdisc over the base.
I Place the filter paper on the top of the spacerdisc.

56. I Compactthe mix soil in the mould using either light compaction
or heavy compaction.For light compaction,compact
the soil in 3 equal layers, each layer being given 55
blows by the 2.6 kg rammer. For heavy compactioncompact
the soil in 5 layers, 56 blows to each layer by the 4.89
kg rammer.
I Remove the collar and trim off soil.
Turn the mould upside down and remove the base plate and
the displacer disc.
I Weigh the mould with compacted soiland determine the
bulk density and dry density.
I Put filter paper on the top of the compacted soil(collar side)
and clamp the perforated base plate on to it.
StaticCompaction
I Calculate the weight of the wet soil at the required water
content to give the desired density when occupying the
standard specimenvolume in the mould from the expression.
Soaking
Place the swell plate with adjustable stem on the soil sample
in the mold and apply sufficientannular weights to produce
an intensity of loading equal to the mass of the subbase and
base courses and surfacing above the tested material.
I Place the tripod with dial indicator on top of the mold and
make an initial dial reading.
I Immerse the mold in water to allow free access of water to
top and bottom of the specimen.During soaking, maintain
the water level in the mold and the soaking tank approximately
25 mm (1 in.) above the top of the specimen.Soak
the specimen96 hours (4 days).

57. At the end of 96 hours, make a final dial reading on the
soaked specimens and calculate the swell as a percentage
of the initial sample length:
]
Penetrationtest
Place the mould assemblywith the surcharge weights on
the penetration test machine.
I Seat the penetration piston at the center of the specimen
with the smallestpossible load, but in no case in excess
of 4 kg so that full contact of the piston on the sample is
established.
I Set the stress and strain dial gauge to read zero. Apply the
load on the piston so that the penetration rate is about 1.25
mm/min.
I Record the load readings at penetrations of 0.5, 1.0, 1.5,
2.0, 2.5, 3.0, 4.0, 5.0, 7.5, 10 and 12.5 mm.
I Note the maximum load and corresponding penetration if it
occurs for a penetration less than 12.5 mm.
Detach the mould from the loading equipment.Take about
20 to 50 g of soil from the top 3 cm layer and determine the
moisture content.

58. Observation
I Optimum Moisture Content (%) =
I Dry Density (g/cc) =
I Weight of empty mould =
I Weight of Mould + CompactedSpecimen=
I Volume of specimen=
I PR Constant =

59. PenetrationResult
I A load penetration curve of load against penetration is then
plotted with load in ordinate axis and penetration in abscissa
axis
I the loads corresponding to 2.5 and 5.0mm penetration values
are noted.
I Sometimes a curve with initial upward concave may also
be obtained due to surface CBR% irregularities and in this
case a correctionis to be done.
I A tangent is drawn at a point of greatest slope.
I The point where this tangent meets penetration axis is the
corrected zero reading of penetration

60. Results