Geo-tech Lab Mannual

Sanghvi Institute Of Management & Science

Experiment No.1

NATURAL AND HYGROSCOPIC MOISTURE CONTENT

OBJECT: Study of determination of natural and hygroscopic water content.

APPARATUS REQUIRED:- (i) Balance accurate to 0.1 g (ii) Non-corrodible airtight

containers (iii) A Dissector with any desiccating agent other than sulphuric acid (iv)

Thermostatically controlled oven with interior of non corroding material to maintain the

temperature between 105 and 11 0 degrees.

THEORY:- Water present in the voids of a soil mass is called as soil water or the

moisture content. The hygroscopic water or contact moisture is the moisture which the

soil particles adsorb from atmosphere by physical forces of attraction. The property of soil

depends upon the moisture content of soil. It is pre-requisite for many other tests. Higher the

temperature less shall be the hygroscopic moisture content. Coarse gained soils have

relatively low hygroscopic moisture due to their limited specific surface. The maximum

hygroscopic capacity of various soils, i.e., the ratio of water absorbed by a dry soil in

saturated

atmosphere at a given temperature to the weight of the oven dried soil has approximately the

following average values; Sands-1.0%, Silts- 7% and clays- 17%.

For determination of moisture content of a soil, the soil sample selected depends upon

the quantity required for good representation, which is influenced by the gradation and

maximum size of particles, and on the accuracy of weighing. The following quantities are

recommended for general lab use:

Size of particles Max quantity of sample, wt in g

Passing 425-micron IS Sieve 25

Passing 2-mm IS Sieve 50

1Civil Engineering Department


Passing 4.75-mm IS Sieve 200

Passing 1 0-mm IS Sieve 1000



Drier the soil higher shall be the weight of the soil taken.

PROCEDURE: The following procedure is adopted to determine the specific gravity of soil:

1. A clean non-corrodible container is weighed with lid, W1.

2. Take a moist soil sample. Place it in container and weigh again with lid, W2.

3. Place the container with soil sample in an oven for drying. The temperature should be

105- 110 degrees because higher temperature may break the crystalline structure

of clay particles and result in- loss of chemically bound water of crystallization.

Lower temperature is recommended for organic soils to avoid oxidation of organic

matter present in the sample. In case of sandy soil complete drying can be achieved in

4 to 6 hours. However, in routine practice samples are dried for 24 hours.

4. After 24 hrs sample is taken out from the oven and placed in desiccators for cooling.

5. The container with dried soil is weighed say, W3.

6. The sample is then left open to the atmosphere so that it absorbs the moisture from the

atmosphere say, W4.

CALCULATION: - The percentage moisture content is calculated as follows:

Moisture content, W = [(W2-W3)/ (W3-W1)]*100

Weight of water, Ww = W2-W3

Weight of solids Ws = W3-W1



Hygroscopic Moisture content = [(W4-W3)/ (W3-W1)]*100

Experiment No.2

LIQUID LIMIT BY CASSAGRANDE APPARATUS

OBJECT: - Study of determination liquid limit of soil using Casegrande Apparatus [IS: 2720

Part V-1985).

APPARATUS:-

(i) Mechanical Liquid limit device:- It consists of a brass cup and carnage, the base

of the device shall be of macerate Number 221 A.

(ii) Grooving Tool:- It is used for making a groove of standard size so as to fill it

while giving the soil filled in the cup a number of blows from a standard height of

1 cm.

(iii) Porcelain evaporating dish: -A porcelain-evaporating dish of about 12 cm

diameters is used for making the soil paste.

(iv) Spatula: - A flexible spatula with the blade about 8 cm long and 2 cm wide is used

for working with the soil.

(v) Balance: - A balance of capacity 200 g and sensitivity of 0.01 g is required to

weigh the soil sample.

(vi) Oven: Thermostatically controlled with interior of non-corroding material to

maintain the temperature between 105 and 110 C.

(vii) Container:- Airtight containers to determine the moisture content are required.

(viii) A 425-micron sieve

(ix) Desiccators

(x) Wash bottle containing distilled water.



SOIL SPECIMEN:- A specimen weighing about 120 g from the thoroughly mixed portion of

the material passing 425micron IS Sieve is taken.

THEORY:- Liquid limit (Wl) is the water content corresponding to the arbitrary limit

between liquid and plastic state of consistency of soil. It may be defined as the minimum

moisture content at which the soil is still in liquid state but having a small shearing

strength against flowing, which can be measured by standard available means. At liquid

limit all soils possess certain small shear strength. This arbitrarily chosen shear strength

is probably the smallest value that is feasible to measure in a standardised procedure.

PROCEDURE:-

Adjustment of the mechanical device:-

The liquid limit device shall be inspected to determine that it is clean, dry and in

good working order, that the cup falls freely and it does not have too much side play at its

hinge. The grooving tool shall also be inspected to determine that it is clean, dry and the

critical dimension is as shown in the figure. By means of the gauge on the handle of the

grooving tool and the adjustment plate, the height through which the cup is lifted and

dropped shall be adjusted so that the point on the cup which comes in contact with the

base fall through exactly one centimeter for one revolution of the handle. The adjustment

plate shall then be secured by tightening the screw.

i. Take about 120 g of air-dried soil from thoroughly mixed portion of the material

passing 425 micron Sieve and mix it with distilled water in an evaporating desiccators

or on a glass plate. Leave the soil for sufficient time so that water may permeate

throughout the soil mass. In case of fat clays, this maturing time may be taken as 24

hours. For an average soil, thorough mixing for about 15 to 30 minutes may be

sufficient. Certain soils may require as much as 40 minutes of continuous mixing

immediately before testing. The prepared paste shall have a consistency that will

require 30-35 drops of the cup.

ii. Take a portion of the paste with the spatula and place it in the center of the cup so that

it is almost half filled. Level off the top of the wet soil symmetrically with the

spatula, so that it is parallel to the rubber base and the maximum depth of the soil is 1 4

Civil Engineering Department


cm.

(a) Determination of mass of Sand in the cone 1 2

I. Mass of sand and cylinder before pouring (g)

2. Mean mass of sand in the cone (g)

(b) Determination of bulk density of sand

3. Volume of calibrating container (cm3)

4. Mean mass of sand and cylinder after pouring in the container (g)

5. Mass of sand tilling the calibrating container (g)M=M1-M3-M2

6. Bulk density of sand pHs = M/V

(C) Bulk density and unit weight of in situ soil

7 Mass of wet oil from the hole (g)

8. Mass sand and cylinder after po11ring in the hole

9. Mass of sand in the hole M, M1-M2-M(g)

10. Bulk density of soil p = M*ps/M in g/cm3

11. Bulk unit weight γv = 9.81 p

(d) Water content determination -

12. Container No.

13. Mass of container + wet soil (g)

14 Mass of container + dry soil (g)

15. Mass of container (g)

16. Mass of dry soil (g)= (13) -(14)

17. Mass of water (g)= (13) - (15)

18 Moisture content t w = r(16)/(17)*100

19 Specific Gravity (G)

20 Void Ratio (e) (19)/



Experiment No.3

PERMEABILITY BY CONSTANT HEAD

OBJECT:- Study of determination of Coefficient of Permeability by Constant Head Method

[IS: 2720 (part XVII)-1966]

APPARATUS REQUIRED:-

(i) Permeameter Mould: - Non-corrodible material having a capacity of 1000 ml with an

internal diameter of 100 ± 0.1 mm and an internal effective height of 127.3 ± 0-1 mm

(ng.l ). The mould is fitted with a detachable base plate and a removable collar

approximately 60 mm high (Fig.2). The internal surface of the mould should be

smooth. The maximum particle size in the soil to be tested in this mould should be 10

mm. For bigger soil particles a bigger mould is used.

(ii) Compaction Equipment:- (a) For Dynamic Compaction:- 50 mm diameter circular

face, weight 2.6 kg and height of fail 310 mm (b) 50 mm diameter circular face,

weight 4.89 kg and height of fall 450 mm.

(iii) Drainage Base:- A base with a porous disc, 12 mm thick having a fitting for

connection to water inlet or outlet (Fig.3). The permeability of the disc should be

more than 10 times the expected permeability of soil. The base should also be

provided with a dummy plate (Fig.4) 12 mm thick and 108 mm in diameter Which to

be used in the place of the porous stone when the soil specimen is compacted in the

mould.

(iv) Drainage Cap:- A cap with an inserted porous dia., 12 mm thick having fitting for

connection to water inlet and outlet (Fig.5). The permeability of the disc should be

more than 10 times the expected permeability of soil. The drainage base and cap

should have fittings for being clamped to the permearneter mould. They should be

provided with leak-proof seals such as rubber 0-rings or gaskets (Fig.6). The



apparatus should be such that there is no gap between the soil specimen and the top

and bottom porous discs when it is assembled ready for the test.

(v) Constant Head Tank:- A suitable water reservoir capable of supplying water to the

Permeameter.

(vi) Vacuum pump

(vii) Miscellaneous Apparatus:- IS Sieves 4.75 mm, mixing pan, graduated cylinder, meter

scale, stop watch, thermometer and de-aired water.

THEORY:- The ease with which water can flow through a saturated soil is known as

permeability. The consolidation process (the rate of settlement of day) depends upon its

permeability. The Knowledge of this property is essential in the solution of problems

involving dewatering, yield of water bearing strata, seepage through earth dams, stability of

earthen dams, and embankments as affected by seepage, settlement, etc. The quantity of

stored water escaping through and beneath an earthen dam depends upon the permeability of

embankment and foundations respectively present in the voids of a soil mass is called as soil

water or the moisture. Coefficient of permeability or simply permeability is usually evaluated

on the basis of Darcy law, which states that the rate of flow through a porous medium is

proportional to the hydraulic gradient. For this law to be valid the flow through soil should be

laminar. This method i.e. Constant Head Method is usually used for predominantly sandy

soils.

PREPARATION OF TEST SPECIMEN:-

(a) Disturbed Sample: - A 2.5 kg sample is taken from a thoroughly mixed air-dried or

oven-dried material. The moisture content is determined (Experiment No.1). The

sample is placed in an airtight container. The desired amount of water (either the

OMC or any specified moisture content) is added to the stored sample soil Spread

evenly over the sample, and after thorough mixing: the material is again placed in the

storage container. The permeameter mould is weighed empty to the nearest gram.

After greasing lightly the inside of the mould it is damped between the compaction



base plate and extension collar. The assembly is kept on & solid base.

All dimensions are in millimeter

DRAINAGE BASE



NOTE:-All dimensions are in millimeters, unless otherwise specified. The dimensional tolerance is ± 1 mm to match the assembly.

EXTENSION COLLAR

The dry density for remoulded soil sample is either MOD as found from Proctor

Compaction test, field density or any other density at which the test is desired- The amount

of oven-dried soil required can be calculated as W =yd*V (V = volume of the mould, Yd

= required density). The amount of water is evaluated by multiplying this with moisture

content (in fraction). The corn active effort may be varied to simulate field conditions. Static

compaction may also be used wherever necessary. For this, attach the 3 cm collar to the

bottom end of the 0.3 liter mould and 2.5 cm collar to its top end. Support the mould

assembly over the 2.5 cm end plug with the 2.5 cm collar resting on the split collar kept

around the 2.5 cm end plug. The 0 3 liter mould should be lightly greased from inside. After

completion of compaction the collar is removed and excess soil is trimmed level with the top

of the mould. The base is detached and the mould full of compacted specimen is weighed.

The mould with the specimen inside is assembled to the drainage base and cap having porous

discs as shown in Fig 6. The porous discs are saturated before assembling the mould.

(b) Undisturbed Sample:- Undisturbed specimen is trimmed in the form-of a cylinder not

larger than about 85 mm diameter and height equal to that of mould. The specimen is placed

centrally over the porous disc of the drainage base fixed to the mould. The annular space

between the mould and the specimen is filled with an impervious material such as cement

slurry or a mixture of 10% dry powdered Bentonite and 90% fine sand by weight to provide

sealing between the soil Specimen and the mould against leakage from the sides. When using

cement slurry the mould is kept on a flat surface other than the porous discs. The drainage

cap is then fixed over the top of the mould

TEST PROCEDURE:-

Saturation: - In case of soils of medium to high permeability the specimen is subjected to

sufficient head, flow or immersion so as to obtain full saturation. Soils of low permeability

require flow under High head for periods ranging from a" day to a week depending upon the

permeability and head. Alternately, in the case of soils having low permeability the specimen



is subjected to a gradually increasing vacuum with bottom outlet dosed so as to remove

air from the soil voids. The vacuum is increased to at least 70 cm of mercury, which is

maintained for 15 minutes or more depending upon the type of soil. Then a very slow

saturation of the specimen with de-aired water from the bottom upwards under full vacuum is

done. When the specimen is saturated both the top and bottom outlets are closed.

Now the specimen is connected through the top inlet to the constant head reservoir.

The bottom outlet is opened and when the steady state of flow has been established, the

quantity of flow for a convenient time intervals is collected and weighed or measured.

Alternatively, the inlet may be at the bottom and water may be collected from the outlet at

top. The collection of the quantity of flow for the same time interval is repeated thrice.

Note I:- In order to ensure laminar flow condition, Cohesion less soils are to be tested under

a low hydraulic gradient, which may be from 0.2 to 0.3 for loose state of compact less and

from 0.3 to 0.5 for denser state of compactness. Coarser the soil the lower shall be the

hydraulic gradient used in the test.

Note II:- De-aired water is used for the test.

OBSERVATION:-

Sample No.

Date

Time

Location of Sample

Bore No.

Depth

Diameter of specimen, in cm =

Length of Specimen (L) in cm =

Area of specimen (A), in cm2 =

Volume of specimen (V) in cm3 =



Specific Gravity of soil (G) =

Tare No. =

Weight of wet soil specimen after test, in g =

Weight of Tare, in g =

Moisture content, w =

Weight of dry specimen + Tare, in g =

Weight of dry specimen. W s in g =

Degree of saturation at the end of test in % =

CALCULATIONS:-

The coefficient of permeability may be obtained from the following equation k =

(Q*L)/(A*h) Where,

k = Coefficient of permeability in cm/s,

G-Rate of low in cm3/s,

Quantity collected in cm3/Time interval in seconds,

L = Length of specimen in cm,

A= Cross sectional area of specimen in cm2,

h = Constant hydraulic head causing the flow in cm,

The temperature correction is applied by the following formula:

Where,

k27 = Coefficient of permeability at 27° C,

k T- Coefficient of permeability at T°C

vT = Coefficient of viscosity at T°C,



v37 - Coefficient of viscosity at 27 "C.

The void ratio e is evaluated as e = (V*G-W)/Ws the degree of saturations is calculated as.

Experiment No.4

PERMEABILITY BY VARIABLE HEAD

OBJECT:- Study of determination of Coefficient of Permeability by Variable Head Method

[IS: 2720 (part XVII)-1966]

APPARATUS REQUIRED:-

(i) Permeameter Mould: - Non-corrodible material having a capacity of 1000 ml with an

internal diameter of 100 + 0.1 mm and an internal effective height of 127.3 ± 0.1 mm

(Fig.1). The mould is fitted with a detachable base plate and a removable collar

approximately 60 mm high (Fig.2). The internal surface of the mould should be

smooth. (The maximum particle size in the soil to be tested in this mould should be 10

mm. For bigger soil particles a bigger mould is used,

(ii) Compaction Equipment:- (a) For Dynamic Compaction: -50 mm diameter circular

face, weight 2.6 kg and height of fall 310 mm (b) 50 mm diameter circular face,

weight 4.89 kg and height offal! 450 mm

(iii) Drainage Base:- A base with a porous disc, ,12 mm thick having a fitting for

connection to water inlet or outlet (Fig.3). The permeability of the disc should be

more than 10 times the expected permeability of soil. The base should also be

provided with a dummy plate (Fig.4) 12 mm thick and 08 mm in diameter Which to

be used in the place of the porous stone when, the soil specimen is compacted in the

mould

(iv) Drainage Cap:- A cap with an inserted porous disc. 12 mm thick having fitting for

connection to water inlet and outlet (Fig.5). The permeability of the disc should be

more than 10 times the expected permeability of soil. This drainage base and cap

should have finings for being clamped to the Permeameter mould. They should be



provided with leak-proof seals such as rubber 0-rings or gaskets (Fig.6). The

apparatus should be such that there is no gap between the specimen and the top and

bottom porous discs when it is assembled really for the test.

(v) Constant Head sink: A suitable water reserve is capable of supplying water to the

Permeameter

(vi) Vacuum Pump

(vii) Unfocused Apparatus: -IS Sieves 4.75 mm, mixing pan, graduated cylinder, meter

scale, stop watch, thermometer and de-aired water.

THEORY:- The ease with which water can flow through a saturated soil is known as

permeability. The consolidation process (the rate of settlement of day) depends upon its

permeability. The knowledge of this property is essential in the solution of problems

involving dewatering, yield of water bearing strata, seepage through earth dams, stability of

earthen dams, and embankments as affected by seepage, settlement ale. The quantity of

stored water escaping through and beneath an earthen dam depends upon the permeability of

embankment and foundations respectively present m the voids of a soil mass is called as soil

water or the moisture. Coefficient of permeability or simply permeability is usually evaluated

on the basis of Darcy (aw, which states that the rate of flow through porous medium is

proportional to the hydraulic gradient. For this law to be valid the flow through soil should be

laminar. This method i.e. Constant Head Method is usually used for predominantly sandy

soils.

PREPARATION OF TEST SPECIMEN:-

(a) Disturbed: Sample: -A 2.5 kg sample is taken from a thoroughly mixed air-dried or oven-

dried material. The moisture content is determined (Experiment No.1). The sample is placed

in an airtight container. The desired amount of water (either the CMC or any specified

moisture content) is added to the stored sample and spread evenly over the sample, and after

thorough mixing: the material is again placed in the storage container. The Permeameter

mould is weighed empty to the nearest gram. After greasing lightly the inside of the mould K



is clamped between the .compaction base plate and extension collar. The assembly is kept on

a solid base.

The dry density for remolded soil sample is either MOD as found from Proctor

Compaction test, field density or any other density at which the test is desired. The amount

of oven-dried soil required car be calculated as W =yd*V (V- volume of the mould, Yd

required density).The amount of water is evaluated by multiplying this with moisture content

(h fraction).The compactive effort may re vary to simulate field conditions. Static

compaction may also be used wherever necessary. For this; attach the 3 cm collar to the

bottom end of the 0.3 liter mould and 2.5 cm collar to it stop end Support the mould assembly

over the 2.5 cm end plug with the 2.5 cm collar resting on the split collar; kept around the 2.5

cm end plug. The 0.3 liter mould should be lightly greased from inside. After completion of

compaction the collar is removed and excess soil is rimmed level with the top of the mould.

The base is detached and the mould full of compacted specimen is weighed. The mould with

the specimen inside is assembled to the drainage base and cap having porous discs as shown

in Fig.6. The porous discs are saturated before assembling trie mould.

(b) Undisturbed Sample:- Undisturbed specimen is trimmed in the form of a cylinder not

larger than about 85 mm in diameter and height equal to that of mould. The specimen is

placed centrally over the porous disc of the drainage case fixed to the mould. The annular

space between the mould and the specimen is filled with ar. impervious material such as

cement slurry or a mixture of 10% powdered Bentor.ile _and SCV = fine sand by weight to

provide sealing between the soil specimen and the round against leakage from the sides.

When using cement slurry the mould is kept on a flat surface other than the porous discs. The

drainage cap is then fixed over the top of the mould.

TEST PROCEDURE:- Saturation: - In the case of soils of medium to high permeability the

specimen is subjected to obtain full saturation. Soils of low permeability require flow.

Under a high head for periods ranging permeability and head. Alternately, in the case of soils

having low increasing vacuum with bottom outlet closed so as to remove air from the soil

voids. The vacuum is increased to at least 70 mm of mercury, which is maintained for 15

minutes or mere depending upon the type of soil. Then a very slow saturation of the specimen

with de-aired water from the bottom upwards under full vacuum is done. When the specimen

is saturated both the top and bottom outlets are dosed.



Now the specimen is connected through the top Inlet to a selected standpipe. The

bottom outlet is opened and the time interval required for the water level to fall from a known

initial head to a known final head as measured have center of the outlet is recorded. This

stand pipe is refilled water and the test is repeated till three successive observations give the

same time interval the time interval is recorded for the drop in head from the same

initial to final values, as in the first determination. Alternatively, time interval after

selecting the suitable initial and final heads, h1 and h2 respectively, time intervals is noted

for head to fall from tv, h 2) and similarly for (hr h2) ira to h2. The time intervals should be

the same; otherwise the observation should be repeated after refilling the M0 order to

ensure laminar flow condition, Cohesiveness soils are to be tested under a hydraulic

gradient, which may be from 0.2 to 0.3 for loose state of compactness and from 0.3 to 0.5.



Experiment No.5

PLASTIC LIMIT

OBJECT:- Study of determination of plastic limit of a soil (IS: 2720 (Part V)- 1965)

APPARATUS:-

(i) Porcelain evaporating dish:-A porcelain-evaporating dish of about 12 cm diameters

is used for making the soil paste.

(ii) Spatula:- A flexible spatula with the blade about 8 cm long and 2 cm wide is used

for working with soil.

(iii) Surface for rolling-Ground-glass plate about 20x15 cm is required for rolling

the soil threat.

(iv)Container: Airtight containers to determine the moisture content are required.

(v) Balance - a balance of capacity 200 g and sensitivity of 0.01 g is required to weigh

the soil sample.

(vi)Oven: -Thermostatically controlled with interior of non-corroding material to

maintain the temperature between 1 05C and 11 0 C.

(vii) Rod:- a rod of 3 mm diameter

SOIL SPECIMEN:- A specimen weighing about 20 g from the thoroughly mixed portion of

the material passing 425-micron IS sieve is taken.

THEORY:- Plastic limit (Wp) is the moisture content at which soil changes from plastic to



semi-solid state. Plastic limit can be defined as minimum water content at which the soil will

just begin crumble when rolled into a thread of approximately 3 mm diameter. Plastic limit

along with liquid limit and related indices is very useful for soil identification. Liquid limits

and plastic limits depend on both the type and amount of clay. Compressibility of soil

increases markedly with increasing plastic limit, whereas strength decreases. On the other

hand, the strength of soil increases with increasing plasticity index. Shearing strength, though

constant al liquid limits, varies at plastic limits for all days. High plastic clay (sometimes

called fat clay) has shearing strength at plastic limit. The shear strength of soil at plastic limit

is about 100 times that at liquid limit i.e. 1.76 kg/cm2.

PROCEDURE:- The following procedure is employed to determine the plastic limit Wp of

the soil sample:

(i) Take about 20 g of air-dried soil passing through 425-micron IS Sieve. Mix it

thoroughly with distilled water in an evaporating dish till the soil mass becomes

plastic enough to be easily moulded with fingers. In case of clayey soils the plastic

soil mass should be left to stand for a sufficient time (24 hours) to allow water to

permeate throughout the soil mass.

(ii) Take about 8 g of this plastic soil, make a ball of it. And roll it on the glass plate with

hand with just sufficient pressure to roll the mass into a thread of uniform diameter

throughout its length. The rate of roiling shall be between 80 and 90 strokes per

minute counting a stroke as one complete motion of the hand forward and back to

starting position again.

(iii) The rolling should be done till the thread diameter is 3 mm. The soil shall then be

needed together to a uniform mass and rolled gain.

(iv) Continue the process until thread just crumbles at 3 mm diameter.

(v) Collect the crumbled soil threads in the airtight container and keep if for water content

determination. The test is repeated twice more. Thus three readings are

obtained for determination.



TABULATION OF OBSERVATIONS:-

The observations are tabulated as show on next page:

Calculations:- The plastic limit may be calculated as shown in the table

Calculation- The liquid limit of soil which corresponds to the moisture content of a paste

which would give 25 mm penetration of the cone may be determined by following equation:

WL = Wx+ 0.01 (25-x) (wx+l5)

Where, WL == liquid limit of the soil w, moisture content of soil paste

corresponding to penetration of x and

x = depth of penetration of cone in mm.

Report:- The average moisture content in whole number as determined from above equation

is reported as the liquid limit.

Note I:- The above equation is valid only for penetration value between 20 to 30 mm.

Note II:- It is assumed that at liquid limit the shear strength of soil is about 17.6 g/cm2

which the penetrometer gives for a depth of 25 mm under total siding load of 148 g.



Experiment No.6

SIEVE SIZE ANALYSIS

OBJECT:- Study of Grain Size Analysis by sieving (Dry analysis) [IS: 2720 (part IV) -

1965]

APPARATUS:-

(i) Balance accurate to 0.1% of the weight of sample to be weighed.

(ii) Set of sieves 100 mm to 75-micron.

(iii) Rubber Pestle and mortar.

THEORY:-

In broad sense soils may be divided into two major groups depending upon the

size of particles namely coarse-grained and. fine- grained. When more than the half

material •is retained on 75-micron sieve it is called as coarse-grained soil On the other

hand if more than a half the material passes through the 75-miron sieve it is called as

fine-grained soil. The coarser fractions of soil consist of gravel and sand. Silt and clay

consists the finer fractions of the soil. Anyone grain of this fraction generally consist

of only one mineral. Grain along with the consistency limits is used for soil

classification. The dry or the mechanical analysis is carried out for coarse-grained

soil. Using a set of standard sieves carries out sieve analysis. According standard, the

sieve number is the mesh with expressed in mm or microns.

PROCEDURE:-



The following procedure can be adopted:

1. Using a riffler, take a representative sample of soil received from the field and dry it in the

oven.

2. Weigh the required quantity of the dry soil. Keep it in a tray and soak it with water [IS:

2720 (part IV)-1965] recommends the following quantities of soil depending the

maximum sieve of soil particles present in the soil mass.

Maximum size of particle present in substantial quantities

(mm)

Weigh of soil to be taken for test

(kg)

63 50

20 6.5

10 1.5

4.75 0.375

3. Puddle the sample thoroughly on the water and transfer the slurry to 4.75 mm sieve. Wash

the slurry with a jet of water. Collect the material retained on 4.75 mm sieve and material

passing through it in a separate container. Keep the material passing retained on 4.75 mm

sieve in the oven.

4. Wash the material through the 4.75 mm sieve through a 15-micron sieve. Collect the

material passing through and retained on 75-micron sieve in separate containers and them

in the oven. The soil passing through the 75-micron sieve is used for sedimentation.

5. Sieve the dried soil retained on 4.75 mm sieve. The following set of sieves is used for

coarse grained soils: IS 63, 20, 10 and 4.75 mm. sieve the dried material retained on 75-

micron sieve. The sieve used for these soils are 21 mm, 600, 425,300, 212, 150 and 75

microns IS sieves. Arranging the various sieves one over the other in the order of their

mesh openings the largest aperture sieve at the bottom, sieving is performed. A receiver is

kept at the bottom and a cover at the top of the whole assembly. The oven-dried sample of

known weight is put on the top sieve, and the whole assembly is fitted oil a sieve-shaking

machine.

6. At least 10 minutes of shaking is desirable for soils with small particles. The portion of



the soil sample retained on each sieve is weighed. The amount of soil retained on each

sieve is noted carefully. The percentage of soil retained on each sieve is calculated on the

basis of the total mass of soil sample taken and from these results percentage passing

through each sieve is calculated.

Note: If a sizable portion is retained on 75-micron sieve (BS 200 number), it should be

washed. This is done by placing the 75-micron sieve on a pan and pouring clean water. In

this process silt and clay particles sticking to the sand particles are dislodged. Two

grams of sodium hexametaphosphate is added per liter of water used. Washing should

be continued till the water passing 75-micron sieve substantially clean. The fraction

retained on the 75-micron sieve size is dried in the oven. The dried portion is then

received again through 2 mm, l mm, 600, 425, 300, 212, 150 and 75 micron IS sieve.

The portion passing 75-micron while washing is also dried separately and its mass is

determined to get percentage finer than 75-micron.

TABULATION AND OBSERVATION:- The observation are tabulated in the following

tabular form.

S.No.

Sieve size in

mm

Weight retained

in gms % weight retained

% cumulative weight

retained % passing

1 25.4

2 20

3 10

4 4.75

5 2.35

6 1.18

7 0.6

8 0.425

9 0.3

10 0.212

11 0.15



12 0.075

SANGHVI INSTITUTE OF MANAGEMENT AND SCIENCE

DEPARTMENT OF CIVIL ENGINEERING

LABORATORY MANUAL

OF

GEOTECHNICAL ENGINEERING – I

SUBMITTED TO:- SUBMITTED BY:-



Mr. Prakash Patidar

(Sr. lecturer)

DEPARTEMENT OF CIVIL ENGINEERING

CONTENTS

Sr.No. NAME OF EXPERIMENT PgNo. REM.

1. Natural and Hygroscopic moisture content 1

2. Liquid Limit By Cassagrande Apparatus 3

3. Permeability By Constant Head 6

4. Permeability By Variable Head 12

5. Plastic Limit 16

6. Sieve Size Analysis 19


Geo-tech Lab Mannual

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