DARSHAN INSTITUTE OF ENGINEERING & TECHNOLOGY RAJKOT · 5 Darshan Institute of Engineering & Technology, Rajkot DEPARTMENT OF CIVIL ENGINEERING 2150609- SOIL MECHANICS LAB MANUAL

DARSHAN INSTITUTE

OF

ENGINEERING & TECHNOLOGY

RAJKOT

SOIL MECHANICS

LAB MANUAL: 2150609

DEGREE CIVIL ENGINEERING

SEMESTER: V

Name of Student

Roll No.

Enrolment No.

Class

Department of Civil Engineering

Geotechnical Engineering Laboratory

Darshan Institute of Engineering and

Technology Rajkot

2 Darshan Institute of Engineering & Technology, Rajkot

DEPARTMENT OF CIVIL ENGINEERING

2150609- SOIL MECHANICS LAB MANUAL

INDEX

Sr. No Name of Experiments Date Pg. No. Mark Sign.

SECTION 1: DETERMINATION OF COMPACTION PROPERTIES

1 Standard Proctor Test (IS : 2720 Part 7-1980)

4

2 Modified Proctor Test (IS : 2720 Part 8-1983)

4

SECTION 2: DETERMINATION OF FIELD DENSITY

3 Proctor Penetration Test 9

SECTION 3: DETERMINATION OF SHEAR PARAMETERS OF SOIL

4 Direct Shear Test (IS : 2720 Part 13-1986)

12

5 UCS Test (IS : 2720 Part 10-1973)

17

6 Vane Shear Test (IS : 2720 Part 30-1987)

22

7 Triaxial Teat (IS : 2720 Part 11-1973)

26

SECTION 4: DETERMINATION OF CONSOLIDATION PROPERTIES

8 Consolidation Test (IS : 2720 Part 15-1986)

37

SECTION 5: DETERMINATION OF SWELL PROPERTIES

9 Free Swell Index Test (IS : 2720 Part 40-1977)

47

10 Swelling Pressure Test (IS : 2720 Part 41-1987)

--

SECTION 6: DETERMINATION OF SUB GRADE STRENGTH

11 CBR Test

(IS : 2720 Part 16-1979) 50

12 Plate Bearing Test (IS : 9214-1979)

--

SECTION 7: SOIL SAMPLING

13 Augur method (Disturbed)

57

14 Hand Operating Sampler (Undisturbed)

57




CONTENTS

Experiment No 1: Light & Heavy Compaction Test .................................................. 4

Experiment No 2: Direct Shear Test ...................................................................... 12

Experiment No 3: Unconfined Compressive Strength (Ucs) Test ............................ 17

Experiment No 4: Vane Shear Test........................................................................ 22

Experiment No 5: Triaxial Test .............................................................................. 26

Experiment No 6: Consolidation Test .................................................................... 37

Experiment No 8: Free Swelling Index Test ........................................................... 47

Experiment No 8: CBR Test .................................................................................. 50

Experiment No 9: Boring Methods of Exploration & Sampling............................... 57




EXPERIMENT NO 1: LIGHT & HEAVY COMPACTION TEST

THEORY:

In geotechnical engineering, soil compaction is the process in which a stress

applied to a soil causes densification as air is displaced from the pores

between the soil grains. It is an instantaneous process and always takes place

in partially saturated soil (three phase system). The Proctor compaction test

is a laboratory method of experimentally determining the optimal moisture

content at which a given soil type will become most dense and achieve its

maximum dry density.

NEED & SCOPE:

Determination of the relationship between the moisture content and density

of soils compacted in a mould of a given size with a 2.5 kg rammer dropped

from a height of 31 cm. the results obtained from this test will be helpful in

increasing the bearing capacity of foundations, Decreasing the undesirable

settlement of structures, Control undesirable volume changes, Reduction in

hydraulic conductivity, Increasing the stability of slope sand so on.

APPARATUS REQUIRED:

Oven

Steel Straightedge - Mixing Tools

Trowel and spatula

Metal Rammer

Spoon

Mould: 1000 cc for light compaction in small mould and 2250 cc for heavy

compaction in large mould

Balance: 10 kg sensitive to 1 g and other of capacity 200 g sensitive to 0.01 g

Sample Extruder: (Optional)




SAMPLE PREPARATION

Light compaction: Heavy compaction:

Small mould 1000cc

A representative portion of air-dried

soil material about 5 kg of material

passing a 19-mm IS Sieve shall be

taken.

Large mould 2207cc



passing 40 -mm IS Sieve shall be

taken.

Small mould 1000cc



passing a 19-mm IS Sieve shall be

taken.

Large mould 2207cc



passing a 37.5-mm IS Sieve shall be

taken.

COMPACTION

Light Compaction: Heavy Compaction:

Small Mould:1000 cc

No of layer 3

No of blow 25

Weight of Hammer 2.6 kg

Falling height of hammer 31 cm

Large mould: 2207 cc

No of layer 3

No of blow 55


Small Mould:1000 cc

No of layer 5

No of blow 25


Falling height of hammer 45 cm

Large mould: 2207 cc

No of layer 5

No of blow 55


AMOUNT OF WATER

Clayey soil Sandy soil

Initial water :12%to 16% below

plastic limit

Water added for each stage: 2 to 4 %

Initial water :3% to 5%

Suitable

Water added for each stage: 1

to 2 %




Light and Heavy compaction mould and rammer

How to Compact soil in Mould

MDD & OMC Graph and Principle of Compaction




PROCEDURE:

1. Obtain a sufficient quantity of air-dried soil and pulverize it. Take about 5

kg of soil passing through 19 mm sieve in a mixing tray for light

compaction in small mould as per above table.

2. Weigh the mould with base plate and apply grease lightly on the interior

surfaces. Fit the collar and place the mould on a solid base.

3. Add initial water to the soil as per criteria given in above table then mix it

thoroughly using the trowel until the soil gets a uniform color.

4. As per guideline given in above table for light compaction in small mould

compact the moist soil in three equal layers using a rammer of mass 2.6

kg and having free fall of 31 cm.

5. Distribute the blows evenly, and apply 25 blows in each layer. Ensure that

the last compacted layer extends above the collar joint.

6. Rotate the collar so as to remove it, trim off the compacted soil flush with

the top of the mould, and weigh the mould with soil and base plate.

7. Extrude the soil from the mould and collect soil samples from the top,

middle and bottom parts for water content determination.

8. Place the soil back in the tray, add a water based on the original soil mass,

and re-mix as in step 3.

9. Repeat steps 4 and 5 and 6 until a peak value of compacted soil mass is

reached followed by a few samples of lesser compacted soil masses.

10. Calculate the bulk density of each compacted soil specimen.

11. Calculate the average moisture content of the compacted specimen and

then its dry density.

12. Plot the dry densities obtained as ordinates against the corresponding

moisture contents as abscissa, draw a smooth compaction curve passing

through them, and obtain the values of maximum dry density (MDD) and

optimum moisture content (OMC).

On the same graph, plot a curve corresponding to 100% saturation,

calculated from




γd = (GS . γw ) / (1+ (wGs/ Sr))

Where,

Sr = degree of saturation,

Gs = specific gravity of solids, and

Ƴw = unit weight of water.

CALCULATIONS:

Bulk Density – γb in g/cc, of each compacted specimen shall be calculated

from the equation:

Ƴ𝑏 =𝑀2 − 𝑀1

𝑉𝑚

Where,

Ml = Empty weight of mould in gm

M2 = Mould + Wet soil in gm mass in g of mould, base and soil; and

Vm = volume of mould in cm3

The dry density, γd in g/cc, shall be calculated from the equation:

Ƴd =100Ƴ𝑏

100 + w

Where,

w = water content of soil in percent.

γb= Bulk Density g/cc

γd= Dry Density g/cc

The dry densities, 𝛄𝐝 obtained in a series of determinations shall be plotted

against the corresponding moisture contents w (%). A smooth curve shall be




drawn through the resulting points and the position of the maximum on this

curve shall be determined.

REPORTING OF RESULTS:

The dry density in g/cc corresponding to the maximum point on the moisture

content/ dry density curve shall be reported as the maximum dry density to

the nearest 0.01.

FIELD CONTROL TEST- PROCTOR NEEDLE

THEORY

Field control tests may be destructive or non-destructive.

Core cutter & Sand Replacement test are destructive test and Proctor

Needles is non-destructive test.

Proctor needle test is used for quick evaluation of maximum soil density in

the field. Standard Compaction curves showing moisture contents versus

densities are drawn in laboratory using standard compaction method and

penetration of the proctor needles are correlated. Proctor needles are also

known as Proctor Penetrometers.

INSTRUMENTS

The instrument consists of a needle attached to a spring loaded plunger, the

stem of which is calibrated to read 0 to 40 kg division. Load stem is graduated

at every 12.5 mm to read depth of penetration and for use with needles of

larger areas. The small penetration stem is also graduated in 12.5 mm

division and is used with needles of smaller areas. Needle points one each of

0.25, 0.5, 1.0, 1.5, 2.0, 3.5 and 6.0 sq. cm. and one tommy pin is supplied.

The needle, fitted with a tip of knowing bearing area, is forced in to the

compacted soil in the mould in the laboratory compaction test at the rate of

1.25 cm per second to depth of 7.5 cm and penetration resistance in kg/cm2

is noted. A calibration chart is prepared by plotting the moulding water

content against penetration resistance.




Proctor Needle and Penetration Resistant Curve




Observation table for Determination of Water Content – Dry Density

Relation Using Light/Heavy Compaction

Type of test (Standard/ Modified proctor test)

Volume of mould (cm3) (1000cm3/2250cm3)

TEST 1 2 3 4 5

Container No.

Empty weight of container

Container + wet soil( gm)

Container+ dry soil (gm)

Mass of mould (gm)

Mass of mould + compacted soil

(gm)

Mass of compacted soil, Wt.(gm)

Bulk density (g/cc)

Needle Resistance(kg/cm2)

Average water content w (%)

Dry density (g/cc )

Dry density at 100% saturation (g/cc )

Result Summary (after plotting a graph)

Maximum Dry Density……………gm/cc

Optimum Moisture Content……………%

CONCLUSION:




EXPERIMENT NO 2: DIRECT SHEAR TEST OR BOX SHEAR

TEST

THEORY & CONCEPT:

The concept of direct shear is simple and mostly recommended for granular

soils, sometimes on soils containing some cohesive soil content. The cohesive

soils have issues regarding controlling the strain rates to drained or

undrained loading.

In granular soils, loading can always assumed to be drained. A schematic

diagram of shear box shows that soil sample is placed in a square box which

is split into upper and lower halves. Lower section is fixed and upper section

is pushed or pulled horizontally relative to other section; thus forcing the soil

sample to shear/fail along the horizontal plane separating two halves. Under

a specific Normal force, the Shear force is increased from zero until the sample

is fully sheared. The relationship of Normal stress and Shear stress at failure

gives the failure envelope of the soil and provide the shear strength

parameters (cohesion and internal friction angle).

NEED & SCOPE:

The value of internal friction angle and cohesion of the soil are required for

design of many engineering problems such as foundations, retaining walls,

bridges, sheet piling.

Direct shear test can predict these parameters quickly.

APPARATUS REQUIRED:

1) Direct shear box apparatus and Loading frame (motor attached).

2) Two Dial gauges, Proving ring, Weighing Balance with accuracy of 0.01g.

3) Sample Extractor (Undisturbed sample) / Sampler for preparation of

remolded sample of dimension (60mm*60mm*25mm).

4) Tamper, Straight edge, Spatula.

5) Filter paper

6) Two porous stones




7) Two corrugated metallic plates with perforation (drained) / metallic

imperforated plates with corrugation (undrained)

8) Metallic Pressure pad Balance - Balance of I kg capacity sensitive to 0.1 g.

PREPARATION OF SPECIMEN:

Undisturbed Specimens - Specimens of required size shall be prepared in

accordance with IS: 2720 (Part I)-1983.

Remoulded Specimens

a. Cohesive soils may be compacted to the required density and moisture

content (MDD & OMC), the sample extracted and then trimmed to

required size. Alternatively, the soil may be compacted to the required

density and moisture content directly into the shear box after fixing the

two halves of the shear box together by means of the fixing screws.

b. Cohesionless soils may be tamped in the shear box itself with the base

plate and grid plate or porous stone as required in place at the bottom of

the box. The cut specimen shall be weighed and trimmings obtained during

cutting shall be used to obtain the moisture content. Using this

information, the bulk dry density of the specimen in the shear box shall be

determined.

PROCEDURE:

Undrained Test -The shear box with the specimen, plain grid plate over the

base plate at the bottom of the specimen and plain grid plate at the top of the

specimen should be fitted into position in the load frame.

The grooves of the grid plates should be at right angles to the direction of

shear the loading pad should be placed on the top grid plate.

The required normal stress should be applied and the rate of longitudinal

displacement/shear stress application so adjusted that no drainage can

occur in the sample during the test.

The upper part of the shear box should be raised such that a gap of

about 1 mm is left between the two parts of the box.




Accessories Placement in Shear box Application of Normal Load

Shearing of Soil in Box Direct Shear Test Instrument

Setup of Test




The test may now be conducted by applying horizontal shear load to

failure or to 20 percent longitudinal displacement, whichever occurs

first.

The shear load readings indicated by the proving ring assembly and the

corresponding longitudinal displacements should be noted at regular

intervals.

CALCULATIONS AND OBSERVATION SHEET

The loads so obtained divided by the corrected cross-sectional area of the

specimen gives the shear stress in the sample. The corrected cross-sectional

area shall be calculated from the following equation:

Corrected area = Ao (1 −𝛿

3)

Where,

Ao = initial area of the specimen in cm2, and

𝛿 = displacement in cm.




From the Graph;

Cohesion:

Angle of Internal Friction:

CONCLUSION

OBSERVATION SHEET

Depth- Size of box(cm)- Mass of soil (gm)-

Rate of strain - Area of box (cm2)- OMC - %

Type of test - Volume of box(cm3)- MDD - gm/cc

Least count of disp. dial gauge (mm/div.):

Proving ring constant (kg/div.):

Dial gauge reading Proving Ring

Reading

(1)

Horizontal Load

(kg)

(2)

Shear Stress

(kg/cm2)

(3)

Normal Stress

(kg/cm2)

(4)

Horizontal

Dial Gauge

Vertical

Dial Gauge

0.5

1.0

1.5

2.0

Remarks-




EXPERIMENT NO 3: UNCONFINED COMPRESSIVE STRENGTH

(UCS) TEST

THEORY

Unconfined compression test also known as uniaxial compression tests, is a

special case of a triaxial test, where confining pressure is zero. UC test does

not require the sophisticated triaxial setup and is simpler and quicker test to

perform as compared to triaxial test. In this test, a cylindrical specimen of soil

without lateral support is tested to failure in simple compression, at a

constant rate of strain. Compressive load per unit area required to fail the

specimen is called unconfined compressive strength of the soil.

NEED AND SCOPE:

It is not always possible to conduct the bearing capacity test in the field.

Sometimes it is cheaper to take the undisturbed soil sample and test its

strength in the laboratory. Also to choose the best material for the

embankment, one has to conduct strength tests on the samples selected.

Under these conditions it is easy to perform the unconfined compression test

on undisturbed and remolded soil sample. Now we will investigate

experimentally the strength of a given soil sample.

APPARATUS REQUIRED:

1. Loading frame with constant rate of movement.

2. Proving ring of 0.01 kg sensitivity for soft soils; 0.05 kg for stiff soils.

3. Soil trimmer, evaporating dish (Aluminum container).

4. Frictionless end plates (Perspex plate with silicon grease coating) of

required diameter (diameter of the plate is selected according to the

diameter of the sample).

5. Dial gauge (0.01 mm accuracy), Dial gauge (sensitivity 0.01mm), Vernier

calipers

6. Balance of capacity 200 g and sensitivity to weigh 0.01 g.

7. Oven, thermostatically controlled with interior of non-corroding material.




8. Soil sample of required dimensions (diameter and height), Sample

extractor and split sampler

Unconfined Compressive Machine Mechanism of Deformation

Test progression




TEST PROCEDURE

Preparation of test specimen:

Undisturbed:

Undisturbed cylindrical specimen may be cut from the bigger undisturbed

sample obtained from the field.

A wire saw may be used to trim the ends parallel to each other. a lathe or

trimmer may be used to trim the specimen to circular cross-section.

Alternatively, field sample may be obtained directly in a thin sampling tube

having the same internal diameter as the specimen to be tested. The split

mould is oiled lightly from inside and the sample is then pushed out of the

tube into the split mould. The split mould is opened carefully and sample

taken is out.

Disturbed

Remolded sample may be prepared by compacting the soil at the desired

water content and dry density in a bigger mould, and then cut by the

sampling tube. Alternatively, remoulded specimen may be prepared directly

in the split mould.

Compression Test

1. Measure the initial length and diameter of the specimen.

2. Put the specimen on the bottom plate of the loading device. Adjust the

upper plate to make contact with the specimen. Set the load dial gauge

and the strain (compression) dial gauge to zero.

3. Compress the specimen until cracks have definitely developed of the stress

strain curve is well past it speak or until a vertical deformation of 20

percent reached. Take the load dial readings approximately at every 1 mm

deformation of the specimen.

4. Sketch the failure pattern; measure the angle between the cracks and the

horizontal, if possible and if the specimen is homogeneous.




Tabulation of observed data

Initial diameter or specimen D0:

Initial length (L0):

Initial area (A0) :

Initial density:

Initial water content:

Determination of Unconfined Compressive Strength.

Sr.

No.

Proving Ring

Reading

Load

(Kg)

Deformation

(cm)

Change in

Length

(∆𝐿)

Axial

Strain

(∈)

Corrected Area

(cm2)

Stress

(kg/cm2)

1

2

3

4

5

6

7

8

Calculation:

Corrected Area = 𝐴0

1−∈

The axial strain ∈ is determined by the following equation: ∈=∆𝑳

𝑳𝒐

Where:

L = Change in specimen, as read from the strain dial.

L0 = Initial length of specimen.




CONCLUSION:




EXPERIMENT NO 4: VANE SHEAR TEST

THEORY:

The objective of this test is to find the shear strength of soil. This test is

performed to find shear strength of a given (generally very soft) soil specimen.

Vane shear test is a useful method of measuring the shear strength of soft

clay. It is a cheaper and quicker method. The test can be conducted in field

as well as in laboratory. The laboratory vane shear test for the measurement

of shear strength of cohesive soils is useful for soils of low shear strength (less

than 0.3 kg/cm2) for which unconfined tests cannot be performed.

NEED AND SCOPE:

The structural strength of soil is basically a problem of shear strength.

Vane shear test is a useful method of measuring the shear strength of

clay. It is a cheaper and quicker method. The test can also be conducted

in the laboratory. The laboratory vane shear test for the measurement of shear

strength of cohesive soils is useful for soils of low shear strength (less than

0.3 kg/cm2) for which triaxial or unconfined tests cannot be performed.

The test gives the undrained strength of the soil. The undisturbed and

remolded strength obtained are useful for evaluating the sensitivity of soil.

APPARATUS REQUIRED:

1. Vane shear apparatus

2. Soft Soil Specimen

3. Specimen container

4. Vernier Caliper

5. Sensitive weighing balance with 0.01 g accuracy




Derivation of formula & Theory

Vane Shear Test Instrument with Vane




PROCEDURE:

Prepare two or three specimens of the soil sample of dimensions of at least

37.5 mm diameter and 75 mm length in specimen. (L/D ratio 2 or 3).

Mount the specimen container with the specimen on the base of the vane

shear apparatus. If the specimen container is closed at one end, it should

be provided with a hole of about 1 mm diameter at the bottom.

Gently lower the shear vanes into the specimen to their full length without

disturbing the soil specimen. The top of the vanes should be at least 10

mm below the top of the specimen. Note the readings of the angle of twist.

Rotate the vanes at a uniform rate say 0.1o/s by suitable operating the

torque application handle until the specimen fails.

Note the final reading of the angle of twist.

Find the value of blade height in cm.

Find the value of blade width in cm.

CALCULATIONS:

Shear Strength, S = 𝑇

𝜋(𝐷2𝐻

2+

𝐷3

6)

Where,

S = Shear Strength of Soil in kg/Cm2

T = Torque in cm Kg

D = Overall Diameter of Vane in Cm

T = 𝑆𝑝𝑟𝑖𝑛𝑔 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡

180°× Difference in Degrees

H = Height of Blade in cm




OBSERVATIONS SHEET

Sr.

No.

Initial

Reading

(Deg. s)

Final

Reading

(Deg.)

Difference

(Deg.)

Spring

Constant

kg cm

G =

𝝅(𝑫𝟐𝑯

𝟐+

𝑫𝟑

𝟔)

S = T × G

kg/cm2

CONCLUSION:




EXPERIMENT NO 5: TRIAXIAL TEST

OBJECT AND SCOPE:

Determination of shear strength parameters of soils under triaxial loading

conditions.

APPARATUS REQUIRED

Triaxial cell,

Compression machine,

Cell pressure application system,

Pore pressure measuring device,

Volume change measuring device,

Proving ring,

Deformation dial gauge,

Split mould,

Trimming knife,

Rubber membrane,

Membrane stretcher,

Rubber ‘O' rings,

Balance,

Apparatus for moisture content determination




Triaxial cell Cell pressure

application system

Compression

machine

Volume change measuring device

Pore pressure measuring device




THEORY:

1. A loading frame in which the load is applied by yoke acting through an

elastic dynamometer, more commonly called a proving ring which used to

measure the load. The frame is operated at a constant rate by a geared screw

jack. It is preferable for the machine to be motor driven, by a small electric

motor.

2. A hydraulic pressure apparatus including an air compressor and water

reservoir in which air under pressure acting on the water raises it to the

required pressure, together with the necessary control valves and pressure

dials.

3. A triaxial cell to take 3.8 cm diameter and 7.6 cm long samples, in which

the sample can be subjected to an allround hydrostatic pressure, together

with a vertical compression load acting through a piston. The vertical load

from the piston acts on a pressure cap. The cell is usually designed with a

non-ferrous metal top and base connected by tension rods and with walls

formed of Perspex.

PROCEDURE:

1. The sample is placed in the compression machine and a pressure plate is

placed on the top. Care must be taken to prevent any part of the machine or

cell from jogging the sample while it is being setup, for example, by knocking

against this bottom of the loading piston. The probable strength of the sample

is estimated and a suitable proving ring selected and fitted to the machine.

2. The cell must be properly set up and uniformly clamped down to prevent

leakage of pressure during the test, making sure first that the sample is

properly sealed with its end caps and rings (rubber) in position and that the

sealing rings for the cell are also correctly placed.

3. When the sample is setup water is admitted and the cell is filled until water

escapes from the bleed valve, at the top, which is then closed.




4. The air pressure in the reservoir is then increased to raise the hydrostatic

pressure in the required amount (say 100 kPa, 150 kPa and 300 kPa

or100kPa, 200 kPa and 300 kPa as per the depth where the sample is brought

and the application requirements). The pressure gauge must be watched

during the test and any necessary adjustments must be made to keep the

pressure constant.

5. The handle wheel of the screw jack is rotated until the underside of the

hemispherical seating of the proving ring, through which the loading is

applied, just touches the cell piston.

6. The piston is then moved down mechanically until it is just in touch with

the pressure plate on the top of the sample, and the proving ring seating is

again brought into contact for the beginning of the test.

OBSERVATION & RECORDING:

The machine is set in motion (or if hand operated the hand wheel is turned

at a constant rate) to give a rate of strain 0.1% to 1% per minute. At particular

intervals of strain, dial gauge readings and the corresponding proving ring

readings are taken, and the corresponding load is determined using proving

ring constant. The experiment is stopped at the strain dial gauge reading for

20% of length of the sample or 20% strain.

Data Sheet for Triaxial Test (UU)

Sample No. :

Length of specimen. : cm

Diameter of specimen. : cm

Initial area of specimen (A0). : cm2

Initial Volume (Vo). : cm3

Strain rate. : mm/minute

Proving ring constant. : kg/division

Strain dial least count (const.) :




OBSERVATION SHEET FOR UU TEST

Cell

pressure

kPa (σ3)

Dial gauge

reading

(divisions)

Deformation mm

(divisions*least

count)

Strain (%), ξ =

(deformation/ht.

of specimen*100)

Proving ring

reading

(divisions)

Load taken (N)

(divisions*provi

ng ring

constant)

Corrected

area (m2 )

= (A0/{1-

ξ/100)

Deviator Stress,

(σd) kPa (= load

taken*corrected

area)/1000

100

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

700




Cell

pressure

kPa (σ3)

Dial gauge

reading

(divisions)

Deformation mm

(divisions*least

count)

Strain (%), ξ =

(deformation/ht.

of specimen*100)

Proving ring

reading

(divisions)

Load taken (N)

(divisions*provi

ng ring

constant)

Corrected

area (m2 )

= (A0/{1-

ξ/100)

Deviator Stress,

(σd) kPa (= load

taken*corrected

area)/1000

200

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

700




Cell

pressure

kPa (σ3)

Dial gauge

reading

(divisions)

Deformation mm

(divisions*least

count)

Strain (%), ξ =

(deformation/ht.

of specimen*100)

Proving ring

reading

(divisions)

Load taken (N)

(divisions*provi

ng ring

constant)

Corrected

area (m2 )

= (A0/{1-

ξ/100)

Deviator Stress,

(σd) kPa (= load

taken*corrected

area)/1000

300

25

50

75

100

125

150

175

200

225

250

275

300

325

350

375

400

425

450

475

500

525

550

575

700




Sample

No.

Bulk

density

(g/cc)

Cell

pressure

(kPa)

Compressi

ve stress

at failure

(kPa)

Strain

at

failure

(%)

Moisture

content,

(%)

Shear

strength

(kPa)

Angle of

shearing

resistance,

(0)

1 2

3

*σ1 = σ3+ σd;

*Plot σd vs , (Deviatory stress vs. strain plot);

*Plot p versus q for the peak values from three tests (Modified failure

envelope);

GENERAL REMARKS:

a) It is assumed that the volume of the sample remains constant and that the

area of the sample increases uniformly as the length decreases. The

calculation of the stress is based on this new area at failure, by direct

calculation, using the proving ring constant and the new area of the sample.

By constructing a chart relating strain readings, from the proving ring,

directly to the corresponding stress.

b) The strain and corresponding stress is plotted with stress abscissa and

curve is drawn. The maximum compressive stress at failure and the

corresponding strain and cell pressure are found out.

c) The stress results of the series of triaxial tests at increasing cell pressure

are plotted as a Modified failure envelope using p = (σ1+σ3)/2 as abscissa and

q = (σ1-σ3)/2 as ordinate. In this diagram a best fit line is plotted with in

which the slope represents the value of ψ while the intercept represents the

value of a.

d) From the relation, sinφ = tan ψ,

a = c* cosφ;

The value of cohesion, c and the angle of shearing resistance, φ will be

determined as the soil shear strength parameters.




CONCLUSION:




Based on Drainage Condition UU test Theory




CU test Theory CD test Theory




EXPERIMENT NO 6: CONSOLIDATION TEST

THEORY:

When a compressive load is applied to soil mass, a decrease in its volume

takes place, the decrease in volume of soil mass under stress is known as

compression and the property of soil mass pertaining to its tendency to

decrease in volume under pressure is known as compressibility. In a

saturated soil mass having its void filled with incompressible water, decrease

in volume or compression can take place when water is expelled out of the

voids. Such a compression resulting from a long time static load and the

consequent escape of pore water is termed as consolidation. Then the load is

applied on the saturated soil mass, the entire load is carried by pore water in

the beginning. As the water begins escaping from the voids, the hydrostatic

pressure in water gets gradually dissipated and the load is shifted to the soil

particles which increases effective stress on them, as a result the soil mass

decrease in volume. The rate of escape of water depends on the permeability

of the soil.

Consolidation of soil is the process of compression by gradual reduction of

pores under a steady applied pressure.

The main purpose of the consolidation test is to obtain soil data required

for predicting the rate and amount of settlement of structures.

Two most important soil properties provided by a consolidation test are the

coefficient of compressibility (ay) though which one can determine the

magnitude of compression and the coefficient of consolidation (cy) which

enable the determination of the rate of compression under a load increment.

The data from laboratory consolidation test also give useful information

about stress history of soil.

Terzaghi theory of one dimensional consolidation is used to extrapolation of

laboratory data to predict the settlement of structure in field.

The data can also be used to develop void ratio (e) versus pressure (p) curve generally

for cohesive soil




NEED AND SCOPE:

The test is conducted to determine the settlement due to primary

consolidation.

a. Rate of consolidation under normal load.

b. Degree of consolidation at any time.

c. Pressure-void ratio relationship.

d. Coefficient of consolidation at various pressures.

e. Compression index.

The above information can be used to predict the time rate and extent of

settlement of structures founded on fine-grained soils. It is also helpful in

analyzing the stress history of soil.

The void ratio (e) of a soil specimen under any applied pressure (p) may be

computed using the following relationship, e = 𝐻−𝐻𝑠

𝐻𝑠

Where,

H = Height of soil specimen at the end of each pressure increment (cm)

Hs = equivalent height of solids (cm), which is determined as follows:

Hs = 𝑊𝑠

𝐺×𝛾𝑤×𝐴

Where,

Ws= dry weight of the specimen

G = specific gravity of the solid particles

𝛾𝑤= unit weight of water (g/cc)

A = cross-sectional area of the soil specimen (cm2)




APPARATUS REQUIRED:

1. Consolidometer consisting essentially;

a) A ring of diameter = 60mm and height = 20mm,

b) Two porous stones

c) Guide ring.

d) Outer ring.

e) Water jacket with base.

f) Pressure pad.

2. Loading device consisting of frame, lever system, loading yoke dial gauge

fixing device and weights.

3. Dial gauge (accuracy of 0.01 mm), Thermostatically controlled oven,

Stopwatch, sample extractor, balance, soil trimming tools, spatula, filter

papers, sample containers.




Apparatus Required

Consolidation Apparatuses




SAMPLE PREPARATION:

1. Undisturbed Sample:

From the sample tube, eject the sample into the consolidation ring. The

sample should project about one cm from outer ring. Trim the sample smooth

and flush with top and bottom of the ring by using wire saw. Clean the ring

from outside and keep it ready for weighing.

2. Remolded sample:

a. Choose the density and water content at which sample has to be compacted

from the moisture-density curve, and calculate the quantity of soil and water

required to mix and compact.

b. Compact the specimen in compaction mould in three layers using the

standard rammers.

c. Eject the specimen from the mould using the sample extractor.

PROCEDURE

Soak the porous stones in water and place the bottom porous stone on the

base of the consolidation cell. Keep a filter paper over the stone. Attach

guide ring to one or both ends of the consolidation ring containing soil

specimen (as required) and place it gently on the porous stone. Place

another filter paper on the top of specimen and keep upper porous stone

and loading point. Adjust a steel ball in the groove of the loading cap to

provide uniform loading on the specimen.

Place this whole arrangement properly in position in the loading device.

Check and adjust the loading beam and the counter balancing system.

Level the loading beam with the help of a spirit level. Clamp the dial gauges

in position for recording the compression/swelling of the soil specimen.

Read the initial dial reading and place a 0.05kg/cm2seating pressure on

the pan of weight hanger. Connect the base plate of the consolidation cell

to water reservoir by means of rubber/plastic tubing for saturating the soil

specimen. Allow the saturation of the specimen for 24 hrs. Or more to

attain an almost constant dial gauge reading.

Select appropriate sequence of pressures to be applied. It is customary




that the pressure applied at any loading stage is twice that of the

proceeding stage pressure. The test, therefore, may be carried out for

loading sequence, to apply pressure on the soil specimen in the range of

0.125, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 kg/cm2. However some other

combination of loads may also be taken as per Table 8.1. The maximum

pressure to be applied should be more than the effective vertical pressure

envisaged due to in-situ over burden and the proposed structure to be

constructed on that soil.

Take the dial gauge readings after application of each load according to a

time sequence i.e. total elapsed such as 0.25, 1.00, 2.25, 4, 6.25, 9, 12.25,

16, 20.25, 25, 36, 49, 64, 100, 144, 196, 225, 256 minutes and thereafter

24 hours. A period of 24 hours is generally sufficient for completion of

primary consolidation of the soil specimen for a particular load. A longer

time. May be required in case of hard soil. i.e., soil containing clay particles

25% or (N) SPT values= 30 or qu i.e. unconfined compressive strength> 4.0

kg/cm2). With the help of the above time sequence it is easy to plot the

specimen thickness against square root of time or logarithm of time. If the

object of the study is to obtain pressure-void ratio relationship only, the

time versus dial gauge readings may be avoided and record only the final

dial gauge reading for each load increment after 24hours.

After completing the dial gauge observations at maximum pressure,

release the applied pressure to zero (0.05 kg/cm'' seating pressure) and

leave the soil specimen to swell by water for 24 hours. Record the final

reading of the dial gauge. If required, the loads may be reduced in stages

and time-swelling readings may also be taken accordingly.

Remove the seating load (0.05 kg/cm') and dismantle the consolidation

ring. Wipe off water from the ring and remove filter papers from both the

ends of the specimen. Weigh the ring and record it as (W') g with the

specimen and then place it in a container and dry in an oven (105°-

110°C).Alternatively push the soil specimen out of the ring carefully so

that no soil particle is lost, weigh the specimen and dry. After drying, weigh

the ring with the specimen and record it as (W3) g. Determine the specific




gravity of the soil from the dried specimen. Place the porous stones in a

container filled with water and boil for about 20-30 minutes and then clean

to remove any soil particle therein for their further use.

CALCULATIONS:

Height of solids (HS):

Is calculated from the equation HS = WS/ (GS.w.A)

Void ratio (e)

Voids ratio at the end of various pressures are calculated from equation e =

(H – HS)/HS

Coefficient of consolidation.

The Coefficient of consolidation at each pressure increment is calculated by

using the following equations:

Cv = 0.197 d2 /t50 (Log fitting method)

Cv = 0.848 d2 /t90 (Square fitting method)

In the log fitting method, a plot is made between dial readings and logarithmic

of time, and the time corresponding to 50% consolidation is determined. In

the square root fitting method, a plot is made between dial readings and

square root of time, and the time corresponding to 90% consolidation is

determined. The values of Cv are recorded in below Table.

Compression Index.

To determine the compression index, a plot of voids ratio (e) Vs log (t) is made.

The virgin compression curve would be a straight line and the slope of this

line would give the compression index Cc.

Coefficient of compressibility.

It is calculated as follows

av= e/

e – Change in void ratio

- Change in vertical stress

Coefficient of permeability.

It is calculated as follows k = Cv.av.w/ (1+eo).




GRAPHS:

1. Dial reading vs. log of time or

2. Dial reading vs. square root of time.

3. Voids ratio vs. log (average pressure for the increment).

OBSERVATION AND READING (LOADING):

Data Sheet for Consolidation Test: Time-Displacement Relationship

Ring Dimensions: Diameter (cm): ____________ Area (cm2): _____________

Height (cm): _____________ Initial Data: Specimen Ht (cm).___________ Specific

Gravity of Soil: ___________ Weight of wet soil + Ring (g): __________ Weight of

Ring (g): ___________ Bulk Density (g/cc): _________

Pressure

Intensity

(Kg/cm2 )

Time

(min)

0

0.25

1

2

4

8

15

30

1 hr




2 hr

3 hr

4 hr

8 hr

24 hr

OBSERVATION AND READING (UNLOADING):

Removed Pressure (kg/cm2 )

Retained Pressure (kg/cm2 ) Dial

Gauge reading

Water Content determination:

Weight of Saturated Sample + Ring (g): ____________

Weight of oven dried soil +Ring (g): ____________

Water Content (%): _________




Data Sheet for Consolidation Test: Pressure-Voids Ratio

Applied

pressure

Final

dial

reading

Change in

specimen

height

Final

specimen

height

Height of

solid

Height

of voids

Void

ratio

Average height

during

consolidation

Fitting

time,

t90

Coefficient of

consolidation

cv





EXPERIMENT NO 8: FREE SWELLING INDEX TEST

OBJECT AND SCOPE:

This standard (Part 40) covers the method for Free Swell Index of soils. [As

per IS: 2720 (Part 40) -1986 (Reaffirmed 2011)]

APPARATUS:

Sieve – 425 micron 1S Sieve.

Glass Graduated Cylinders - Two100-ml Capacity

PROCEDURE:

Take two 10 g soil specimens of oven dry soil passing through 425 micron IS

Sieve.

Each soil specimen shall be poured in each of the two glass graduated

cylinders of 100 ml capacity.

One cylinder shall then be filled with kerosene and the other with distilled

water up to the 100 ml mark. After removal of entrapped air (by gentle shaking

or stirring with a glass rod), the soils in both the cylinders shall be allowed to

settle. Sufficient time (not less than 24 h) shall be allowed for the soil sample

to attain equilibrium state of volume without any further change in the

volume of the soils.

The final volume of soils in each of the cylinders shall be read out.

CALCULATION:

The level of the soil in the kerosene graduated cylinder shall be read as the

original volume of the soil sample &, kerosene being a non-polar liquid does

not cause swelling of the soil.

The level of the soil in the distilled water cylinder shall be read as the free

swell level. The free swell index of the soil shall be calculated as follows:





Free Swelling After 24 Hr.





Free swell index, percent =𝑉𝑑−𝑉𝐾

𝑉𝐾×100

Where,

Vd = the volume of soil specimen read from the graduated cylinder

containing distilled water, and

Vk = the volume of soil specimen read from the graduated cylinder

containing kerosene.

CALCULATION:

CONCLUSION:





EXPERIMENT NO 8: CBR TEST

THEORY:

California Bearing Ratio (CBR) is defined as the ratio expressed in percentage

of force per unit area required penetrating a soil mass with a circular plunger

of 50 mm diameter at the rate of 1.25 mm/min to that required for

corresponding penetration in a standard material. Tests are performed out on

natural or compacted soils in water soaked or un-soaked conditions and the

results so obtained are compared with the curves of standard test.

APPARATUS REQUIRED:

1. CBR mould with detachable perforated base plate

2. Spacer disc with a removable handle (to be placed inside the mould)

3. Collar of 50mm high

4. Penetration plunger of 50 mm diameter

5. One annular and a few slotted surcharge masses 2.5 kg each 6. Rammer

(2.6 kg with 310mm drop for standard proctor results) and (4.89 kg with

450mm drop for modified proctor results)

6. Straight cutting edge

7. Loading machine of 50 kN capacity fitted with a calibrated proving ring to

which plunger has to be attached

8. Penetration measuring dial gauge of 0.01mm accuracy

9. Soaking tank

10. Swelling gauge consisting of perforated plate with adjustable extension

stem

PREPARATION OF TEST SPECIMEN:

The test may be performed:

a) On undisturbed specimens, and

b) On remoulded specimens which may be compacted either statically or

dynamically.





Soil Sample -The material used in the remoulded specimen shall pass a 19-

mm IS Sieve.

Allowance for larger material shall be made by replacing it by an equal amount

of material which passes a 19-mm IS Sieve but is retained on 4.75-mm IS

Sieve.

Statically Compacted Specimens

The mass of the wet soil at the required moisture content to give the desired

density when occupying the standard specimen volume in the mould shall be

calculated, A batch of soil shall be thoroughly mixed with water to give the

required water content. The correct mass of the moist soils shall be placed in

the mould and compaction obtained by pressing in the displacer disc, a filter

paper being placed between the disc and the soil.

Dynamically Compacted Specimen

For dynamic compaction, a representative sample of the soil weighing

approximately 4.5 kg or more for fine-grained soils and 5.5 kg or more for

granular soils shall be taken and mixed thoroughly with water. If the soil is

to be compacted to the maximum dry-density at the optimum water content

determined in accordance with IS: 2720 (Part 7)-1980 or IS: 2720 (Part 8)-

1983, the exact mass of soil required shall be taken and the necessary

quantity of water added so that the water content of the soil sample is equal

to the determined optimum water content.





CBR Apparatuses

Load vs. Penetration Graph





PROCEDURE:

Test for Swelling:

A filter paper shall be placed over the specimen.

Weights to produce a surcharge equal to the weight of base material and

pavement to the nearest 2.5 kg shall be placed on the compact soil

specimen.

The whole mould and weights shall be immersed in a tank of water allowing

free access of water to the top and bottom of the specimen.

The tripod for the expansion measuring device shall be mounted on the

edge of the mould and the initial dial gauge reading recorded.

This set-up shall be kept as such undisturbed for 96 hours.

Noting down the readings everyday against the time of reading.

A constant water level shall be maintained in the tank throughout the

period.

At the end of the soaking period, the final reading of the dial gauge shall

be noted, the tripod removed and the mould taken out of the water tank.

The free water collected in the mould shall be removed and the specimen

allowed draining downward for 15 minutes. Care shall be taken not to

disturb the surface of the specimen during the removal of the water.

The weights, the perforated plate and the top filter paper shall be removed

and the mould with the soaked soil sample shall be weighed and the mass

recorded.

PENETRATION TEST:

The mould, containing the specimen, with the base plate in position, but

the top face exposed, shall be placed on the lower plate of the testing

machine.

To prevent upheaval of soil into the hole of the surcharge weights, 2.5 kg

annular weight shall be placed on the soil surface prior to seating the

penetration plunger after which the remainder of the surcharge weights

shall be placed.





The initial load applied to the plunger shall be considered as the zero load

when determining the load penetration relation.

Load shall be applied to the penetration plunger so that the penetration is

approximately 1.25 mm per minute. Reading of the load shall be taken at

penetrations of 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 4.0, 5.0, 7.5, 10.0 and 12.5 mm

The maximum load and penetration shall be recorded it if occurs for a

penetration of less than 12.5 mm.

About 20 to 50 g of soil shall be collected from the top 30 mm layer of the

specimen and the water content determined.

CALCULATION:

Load Penetration Curve:

The load penetration curve shall be plotted.

Bearing Ratio:

California bearing ratio = 𝑃𝑇

𝑃𝑆 X 100

Where,

PT = corrected unit (or total) test load corresponding to the chosen penetration

from the load penetration curve, and

PS = unit (or total) standard load for the same depth of penetration as for PT

taken from Table

REPORT:

The CBR value shall be reported correct to the first decimal place.





PERFORMA FOR CALIFORNIA BEARING RATIO TEST:

Dial

Gauge Reading

Penetration

in (mm)

Proving

Ring (Red)

Load (Kg)

Corrected

Load (kg)

Load in (kg/cm2)

0 0.0

50 0.5

0 1.0

50 1.5

0 2.0

50 2.5

0 3.0

50 3.5

05 4

0 4.5

50 5

0 5.5

50 6

0 6.5

50 7

0 7.5

0 8

50 8.5

0 9

50 9.5

0 10

50 10.5

0 11

50 11.5

0 12

50 12.5





STANDARD LOAD

Penetration Depth (mm)

Unit Standard Load (Kg/cm2 )

Total Standards load (Kg)

2.5 70 1370

5.0 105 2055

7.5 134 2630

10.0 162 3180

12.5 183 3600

RESULT

From Graph Correction CBR at 2.5 mm CBR at 5 mm

CBR-1

CBR-2

CBR-3

Average CBR

CONCLUSION:





EXPERIMENT NO 9: BORING METHODS OF EXPLORATION &

SAMPLING

The boring methods are used for exploration at greater depths where direct

methods fail. These provide both disturbed as well as undisturbed samples

depending upon the method of boring. In selecting the boring method for a

particular job, consideration should be made for the following:

The materials to be encountered and the relative efficiency of the various

boring methods in such materials

The available facility and accuracy with which changes in the soil and ground

water conditions can be determined possible disturbance of the material to

be sampled

The different types of boring methods are:

Displacement boring

Wash boring

Auger boring

Rotary drilling

Percussion drilling

Continuous sampling

DISPLACEMENTBORING

It is combined method of sampling & boring operation. Closed bottom

sampler, slit cup, or piston type is forced in to the ground up to the desired

depth. Then the sampler is detached from soil below it, by rotating the piston,

& finally the piston is released or withdrawn. The sampler is then again forced

further down & sample is taken. After withdrawal of sampler & removal of

sample from sampler, the sampler is kept in closed condition & again used

for another depth.

Features: Simple and economic method if excessive caving does not occur.

Therefore not suitable for loose sand. Major changes of soil character can be





detected by means of penetration resistance. These are 25mm to 75mm holes.

It requires fairly continuous sampling in stiff and dense soil, either to protect

the sampler from damage or to avoid objectionably heavy construction pit.

Wash boring: It is a popular method due to the use of limited equipments.

The advantage of this is the use of inexpensive and easily portable handling

and drilling equipments. Here first an open hole is formed on the ground so

that the soil sampling or rock drilling operation can be done below the hole.

The hole is advanced by chopping and twisting action of the light bit. Cutting

is done by forced water and water jet under pressure through the rods

operated inside the hole. In India the “Dheki” operation is used, i.e., a pipe of

5cm diameter is held vertically and filled with water using horizontal lever

arrangement and by the process of suction and application of pressure, soil

slurry comes out of the tube and pipe goes down. This can be done upto a

depth of 8m –10m (excluding the depth of hole already formed beforehand)

Just by noting the change of colour of soil coming out with the change of soil

character can be identified by any experienced person. It gives completely

disturbed sample and is not suitable for very soft soil, fine to medium grained

cohesionless soil and in cemented soil.

Auger Boring this method is fast and economical, using simple, light, flexible

and inexpensive instruments for large to small holes. It is very suitable for

soft to stiff cohesive soils and also can be used to determine ground water

table. Soil removed by this is disturbed but it is better than wash boring,

percussion or rotary drilling. It is not suitable for very hard or cemented soils,

very soft soils, as then the flow into the hole can occur and also for fully

saturated cohesionless soil.

Rotary drilling method of boring is useful in case of highly resistant strata.

It is related to finding out the rock strata and also to access the quality of

rocks from cracks, fissures and joints.

It can conveniently be used in sands and silts also.

Here, the bore holes are advanced in depth by rotary percussion method

which is similar to wash boring technique. A heavy string of the drill rod is

used for choking action. The broken rock or soil fragments are removed by





circulating water or drilling mud pumped through the drill rods and bit up

through the bore hole from which it is collected in a settling tank for

recirculation. If the depth is small and the soil stable, water alone can be

used. However, drilling fluids are useful as they serve to stabilize the bore

hole. Drilling mud is slurry of bentonite in water. The drilling fluid causes

stabilizing effect to the bore hole partly due to higher specific gravity as

compared with water and partly due to formation of mud cake on the sides of

the hole. As the stabilizing effect is imparted by these drilling fluids no casing

is required if drilling fluid is used. This method is suitable for boring holes of

diameter 10cm, or more preferably 15 to20cm in most of the rocks. It is

uneconomical for holes less than 10cm diameter. The depth of various strata

can be detected by inspection of cuttings

Percussion Drilling In case of hard soils or soft rock, auger boring or wash

boring cannot be employed. For such strata, percussion drilling is usually

adopted. Here advancement of hole is done by alternatively lifting and

dropping a heavy drilling bit which is attached to the lower end of the drilling

bit which is attached to the cable. Addition of sand increases the cutting

action of the drilling bit in clays. Whereas, when coarse cohesionless soil is

encountered, clay might have to be added to increase the carrying capacity of

slurry. After the carrying capacity of the soil is reached, churn bit is removed

and the slurry is removed using bailers and sand pumps. Change in soil

character is identified by the composition of the outgoing slurry. The stroke

of bit varies according to the ground condition. Generally, it is 45-100cm in

depth with rate of 35-60 drops/min. It is not economical for hole of diameter

less than 10cm. It can be used in most of the soils and rocks and can drill

any material. One main disadvantage of this process is that the material at

the bottom of the hole is disturbed by heavy blows of the chisel and hence it

is not possible to get good quality undisturbed samples. It cannot detect thin

strata as well.





Continuous sampling

The sampling operation advances the borehole and the boring is accomplished

entirely by taking samples continuously. The casing is used to prevent the

caving in soils. It provides more reliable and detail information on soil

condition than the other methods. Therefore it is used extensively in detailed

and special foundation exploration for important structures. It is slower

method and more expensive than intermittent sampling. When modern rotary

drilling rigs or power driven augers are not available, continuous sampling

may be used to advantage for advancing larger diameter borings in stiff and

tough strata of clay and mixed soil. In the Boston district, corps of Engineers

has made faster progress and reduced cost by use of continuous sampling in

advancing 3-inch diameter borings through compact gravelly glacial till,

which is difficult to penetrate by any boring method.

SOIL SAMPLINGS AND SAMPLERS

Soil Sampling In general soil samples are categorized in to 2 types of

samples.

Disturbed samples: The structure of the soil is disturbed to the

considerable degree by the action of the boring tools or the excavation

equipments.

The disturbances can be classified in following basic types: Change in the

stress condition, Change in the water content and the void ratio, Disturbance

of the soil structure, Chemical changes, Mixing and segregation of soil

constituents The causes of the disturbances are listed below: Method of

advancing the bore hole, Mechanism used to advance the sampler,

Dimension and type of sampler, Procedure followed in sampling and boring.

If all the constituents are present in the sample which represents the same

soil type from any place, then it is called a representative sample. In the

remolded sample the engineering properties get changed due to remoulding

Undisturbed samples: It retains as closely as practicable the true in-situ

structure and water content of the soil. For undisturbed sample the stress

changes cannot be avoided. The following requirements are looked for: No





change due to disturbance of the soil structure, No change in void ratio and

water content, No change in constituents and chemical properties

The following Different types of samplers:

Standard split spoon

Piston samplers Piston type sampler

Preservation of samples

Shelby tube etc.





DIFFERENT TYPES OF BORING METHOD AND SAMPLERS

AUGER BORING WASH BORING ROTARY BORING PERCUSSION BORING

SHELBY TUBE SAMPLER OPEN DRIVE SAMPLER PISTON SAMPLER STANDARD SPLIT SPOON

SAMPLER IN





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DARSHAN INSTITUTE OF ENGINEERING & TECHNOLOGY RAJKOT · 5 Darshan Institute of Engineering & Technology, Rajkot DEPARTMENT OF CIVIL ENGINEERING 2150609- SOIL MECHANICS LAB MANUAL