Lab Course Work

8/2/2019 Lab Course Work

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School of Civil Engineering

Module CE2SMG

Physical Properties and Compaction of Soils

G2 and G3 Laboratory Reports

Giannis Kallika1027449

University of Birmingham

College of Engineering and Physical Sciences

School of Civil Engineering

Edgbaston

Birmingham

B15 2TT

United Kingdom (Date 27/02/2012)


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Table of Contents

Executive Summary 1

1.Introduction 2

1.1 Aim and Objectives 2

1.2. Experimentation Procedures 2

1.2.1 Triaxial shear stress test 2

1.2.2 Sieving Test 2

1.2.3 Dieter Compaction Test 2

1.2.4 Penetrometer Test 2

1.2.5 Oedometer Test 2

1.3 Standards Followed 21.4 Soils 2

1.5 Structure of the report 2

2. Results 3

2.1 Compaction Results 3

2.2 Plastic Limits and Activity 3

2.3 Permeability of the Compacted Soil 4

2.4 Particle Size Distribution 5

2.5 Untrained Shear Strength 5

3. Discussion 6

3.1 Test Description 6

3.1.1 Triaxial Shear Stress 6

3.1.2 Sieving Test 6

3.1.3 Compaction Test 6

3.1.4 Cone penetrometer method and Roll test 6

3.1.5 Oedometer Test 6

3.2 Data description from an engineering point of view 7

3.2.1 China clay 7

3.2.2 China clay & Bentonite 7

3.2.3 Silty Clay 7

3.2.4 Clayey Clay 7

3.3 Identification of soils 8

3.3.1 Initial Categorisation 8

3.3.2 Secondary Categorisation 8

4. Conclusion 8


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5. References 9

List of FiguresFigure 1Compaction Test Results with Air void curves 3

Figure 2- Penetrometer Cone Test result 4

Figure 3- Particle size Distribution curve of all soils 5

Figure 4 Undrained Shear strength results of SL-SMCC-2952 6

List of Tables

Table 1- Summary of the results 1

Table 2-Brief Description of the soils 2

Table 3- Dry Densities and Water Content 3

Table 4- Plastic and Liquid limits & indexes (incl. Activity) 3

Table 5- Oedometer Test results and coefficient of permeability 4

Table 6-Undrained shear strength results 5

List of Symbols

Symbol Unit Definition

m m Metre

mm mm Millimetre

m MicroAc Dimensionless Activity

k m/s Coefficient of Permeability

k k kilo

Pa Pa Pascal

LL % Liquid Limit

PL % Plastic Limit

PI % Plasticity Index

LI dimensionless Liquidity IndexCu Apparent Cohesion (Undrained)


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A m2

Area of specimen

V m3

Volume of specimen

Cv m2/s Coefficient of Consolidation

Hi mm Initial height

Hf mm Final height

ei dimensionless Initial void ratio

ef dimensionless Final void ratiow kN/m

3Water unit weight

OMC % Optimum moisture content

Su kPa Undrained Shear Strength

t90 min Square root of time when 90%consolidation occurs

kg/m3 Density


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1

Executive Summary

The report investigates the following soil samples, SL-SMCC-2961, SL-SMCC-2957, SL-SMCC-

2952, and SL-SMCC-2964, and recommends the most suitable for the construction of the low

permeability blanket. The four soils are identified using various tests, such as the Oedometer test,

Penetrometer test, Dieter Compaction test and Triaxial test and a summary of the tests results canbe found in the table below. By using the Plasticity Index we identified the four soils.

Specification/

Soil CodeSL-SMCC-2961 SL-SMCC-2957 SL-SMCC-2952 SL-SMCC-2964

Unit weight, at

least 12 kN/m3

11 kN/m3

No

12 kN/m3

Yes

17 kN/m3

Yes

14 kN/m3

Yes

Air voids after

compaction

5% No No Yes Yes

Water content

less than plastic

limit of the soil

Yes Yes Yes Yes

Permeability1.5x10

-9 7.96 x10-10

Yes2.70 x10-10

Yes2.83 x10-10

Yes4.55 x10-10

Yes

Not prone to

shrink or swell

(activity)

1.68 (active)

No

0.27 (Inactive)

Yes

0.94 (Normal)

Yes

0.51 (Inactive)

Yes

Constant Shear

strength with

changes to

water content

41kPa 51kPa 132kPa 128kPa

Plasticity index 96% 21% 24% 33%

Soil NameChina and

Bentonite clay China clay Clayey silt Silty clay

Table 1- Summary of the results

The soil that passes all the requirements is the Clayey silt because it has a high value of Shear

strength, it will not collapse due to seepage of water, it is inactive (soil particles do not bond with

water giving high plasticity), as a result the soil will not shrink or swell, and the compaction will

give the required density with less than 5% water and air present in the soil. Therefore the Shear

Strength will be high and the soil will not fail due to loading.


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1 Introduction1.1Aim and Objectives

The aim is to identify the four given samples and choose the most suitable by taking into

consideration the six end product specifications. The results of the Oedometer test,

Penetrometer test, Dieter Compaction test and Triaxial test will be analysed and the soil

that meets all the specifications will be chosen for the construction of the Low

Permeability Blanket

1.2Experimentation Procedures(1)The experiment has been carried out by using the following tests:

1.2.1 Triaxial shear stress testPlot a graph of stress against strain and by taking the maximum value we

calculate the maximum shear strength of the soil being tested

1.2.2 Sieving testThe soil is identified by the percentage of particles passing through each sieve

which has a known filtering size1.2.3 Dieter compaction test

The soils dry density is determined and by using the compaction curve, the void0,5,10 % ratio can be analysed and discussed

1.2.4 Penetrometer testThe soils plastic index can be found by using this testsince the tests aim is tofind the plastic and liquid limit.

1.2.5 Oedometer testLoad is applied to the sample and the penetration of the soil is measured (change

in height). Using the Square Root method, the coefficient of consolidation and

the change in height, the coefficient of permeability is measured.

1.3Standards followed(2)All of the above tests except the Dieter test follow the British Standard code 1377, year

of 1990.

1.4SoilsSoil name Grain size

)Behaviour

)

English China Clay China clay


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reasons of which soils is which will be presented with the aid of diagrams and tables.

The report will come to a conclusion with a summary of the key pertinent findings

presented in the previous sections.

2 Results2.1Compaction Results

Figure 1Compaction Test Results with Air void curves

Soil Sl-2952 Sl-2964 Sl-2957 Sl-2961

Water Content 13% 23% 29% 21%

Maximum Dry Density 1894kg/m3

1518kg/m3

1379kg/m3

1353kg/m3

95% Dry Density 1880kg/m3

1442kg/m3

1310kg/m3

1286kg/m3

95% Dry Unit Weight 17kN/m

314kN/m

312kN/m

311kN/m

3

Table 3- Dry Densities and Water Content

2.2Plastic Limits and ActivitySoil Sl-2952 Sl-2964 Sl-2957 Sl-2961

Plastic Limit 3% 25% 33.3% 27%

Liquid Limit 27% 59% 54.9% 123%

Water Content 13% 23% 29% 21%

PlasticityIndex 24% 33% 21% 96%

Liquidity 0.4 -0.5 -1.9 -0.06

Dietert Com action Test Results for the soils


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4

Index


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5

40

50

60

70

80

90

100

1 10 100 1000

PercentagePas

sedThrough(%)

Log particle size (m)

Particle Size Distribution

Soil 2957

Soil 2961

Soil 2952

Soil 2964

Table 5- Oedometer Test results and coefficient of permeability

2.4Particle Size Distribution

Figure 3- Particle size Distribution curve of all soils

2.5Untrained Shear Strength

Soil Sl-2952 Sl-2964 Sl-2957 Sl-2961

Av. Max strength 264kPa 256kPa 102kPa 82kPa

Su 132 kPa 128 kPa 51 kPa 41 kPa

Table 6-Undrained shear strength results

N 1.0E+05 1.0E+05 1.0E+05 1.0E+05mv m

2/N 4.6E-07 2.0E-07 4.6E-07 5.4E-07

h90 m 0.01459 0.018472 0.014982 0.015083

t90 min 8 30 14 16

d m 7.46E-03 9.29E-03 7.60E-03 7.73E-03Tv - 0.848 0.848 0.848 0.848

Cv m/s 9.8E-08 4.3E-08 5.8E-08 5.2E-08

N 10000.00 10000.00 10000.00 10000.00k m/s 4.53E-10 7.96E-11 2.70E-10 2.83E-10

Required K

value 1.5E-09 1.5E-09 1.5E-09 1.5E-09


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Figure 4 Undrained Shear strength results of SL-SMCC-2952

3. Discussion

3.1Test Description3.1.1 Triaxial Shear Stress(5)

Since every solid has an upper limit to how much shear stress it can support, a shear Triaxial test is

performed to find this value. Due to errors that might be present, a line of best fit has been used and

the equation of the line is differentiated as to find x. Then by using the value of x the maximum

shear strength is calculated.

3.1.2 Dry SievingIn order to classify which soil is which a sieving test is used. An amount of soil is weighted and it is

poured into the nest of sieves. The first sieve has the largest screen openings and the openings

decrease as the soil goes to the bottom. Each sieve is weighted and then by using its diving each

weight with the initial, a percentage of the particles passing is calculated.

3.1.3 Compaction testThis test method uses a hammer to compact the soil in order to remove most of the voids and findthe dry density of the soil. The value of the optimum water content and maximum dry unit weight is

determined from the compaction curve. A concern about the laboratory-human errors was raised;

therefore a best fit line of the compaction curve is made in order to show how the compaction curve

should be.

3.1.4 Cone penetrometer method and Roll testThe Cone penetrometer test is used to calculate the liquid limit of the sample.

The roll test is used to find the plastic limit of the sample and it is performed by rolling the sample

into a thread approximately 1/8 inch in diameter. By finding the plastic limit and liquid limit, the

plasticity index can be calculated. The Activity can be found by dividing the PI with the percentage

of 2m passing through and this will determine whether the soil will shrink or swell with changes inwater conditions.3.1.5 Oedometer test


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The Oedometer test is performed to calculate the coefficient of permeability and the coefficient of

consolidation. It stimulates the one dimensional deformation and drainage conditions that the soil

experience. A different mv and cv values are calculated because in the test of soil 2952 the final void

ratio were calculated as 0 which is wrong since there is always a small percentage of voids in the

soil.

3.2

Data from an engineering point of view3.2.1 China clay 2957According to the Table 3, the degree of compaction of the China clay which is the unit

weight is the second minimum. Therefore, the voids present in the sample are more than 5%

which reduces the strength of the soil. By using this information, the soil fails the

specification. Although the liquid limit is moderate, the plastic limit is low resulting in low

plasticity index classifying (according to the Table 4) the soil as inactive therefore it will

not swell or shrink.(6)

3.2.2 China clay & Bentonite 2961According to the Table 3, the degree of compaction of the China clay which is the unit

weight is the minimum. Therefore, the voids present in the sample are more than 5% which

reduces the strength of the soil and making it prone to shrink and swell. On the other hand, it

is the only soil that has the highest plasticity index (due to the nomenclature of Bentonite),

therefore it is able to undergo deformation without cracking. According to the table 4 it is

classified as an active soil, resulting in a soil that is prone to swelling or shrinking. The

coefficient of permeability calculated from the Oedometer test, according to Table 5, is the

lowest; therefore the water will not be able to flow in the soil resulting in an increase of the

volume. By using this information, the soil fails the specification.

3.1.1 Silty Clay 2964 from Wembley. Since both of the soils contain the same material, only the ratio changes, they have samebehaviour.The soil has the same initial and final dry density; therefore the soils particlesare well graded and thus a void reduction to less than 5% is achieved. Due to the good

compaction of the soil, the unit weight is 14kN/m3

resulting in high shear strength of the

soil. In Table 4, the soils activity is set to be inactive, meaning that it will not swell orshrink. The coefficient of permeability is lower than the others enabling the water to pass

through it (reduces the rate of settlement of a saturated soil) and its coefficient of

consolidation is also low resulting in high shear strength. It has a low plasticity index,

therefore it will crack more or rupture more when deformed compared to the other soils. The

soil has the second highest shear strength 128kPa and can withstand high stresses.3.1.2 Clayey silt 2952 from SkelmersdaleAccording to the soils compaction curve in Figure 1, the Silty clays particles are wellgraded resulting in a good compaction. Thus, void reduction to less than 5% is achieved.

Due to the good compaction of the soil, the unit weight is 17kN/m3

resulting in high shear

strength of the soil. In Table 4, the soils activity is set to be normal, meaning that it will notswell or shrink but it will if the water is drained and untrained in cycles. The coefficient of

permeability is lower than the others enabling the water to pass through it(7)

(reduces the rate

of settlement of a saturated soil) and its coefficient of consolidation is also low resulting in

high shear strength. It has a low plasticity index, therefore it will crack more or rupture more

when deformed compared to the other soils. The soil has the highest shear strength, thus it is

classified as cohesive soil, and can withstand high stresses. This soil is chosen for the


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construction of the Low Permeability blanket because it has the highest shear strength

132kPa, it has a normal activity index, therefore it will not swell in the presence of water

and it passes the permeability requirement, less than 1.5 x10-9

3.2 Identification of soils3.2.1 Initial Categorisation

Since the two quarried soils are sieved, they have smaller particles than the soils from the

construction projects; we can categorize the four samples into two groups and then subcategorize

them to find their corresponding names.

According to Figure 3, the quarried soils are 2961 & 2957 because they have high percentage of

particles passing through the first sieves. Therefore in first group (which consist of the quarried

soils) there is the China Clay & the blend of China clay and Bentonite and in the second group there

is the Silty clay and the clayey silt.

3.2.2 Subcategorize the groupBentonite has bigger particles than China clay and by using Figure 3it is found that the 2961 has

less particles passing through the 22m sieve compared to the soil that is mixed with Bentonite.Also by using and comparing the results in Table 4, we can identify that 2961 is the soil with the

Bentonite since Bentonite has a high Liquid Limit.

According to Figure 3, the 2952 is the clayey silt and 2964 is the Silty clay because clay soils tend

to have higher Plasticity Index than Silt soils.

4 ConclusionThis report has been prepared to show the experimental test results of four different soil types.

These tests are particle size distribution, compaction, Atterberg limits, consolidation and Triaxial.

Specification/

Soil CodeSL-SMCC-2961 SL-SMCC-2957 SL-SMCC-2952 SL-SMCC-2964

Unit weight, at

least 12 kN/m3

11 kN/m3

No

12 kN/m3

Yes

17 kN/m3

Yes

14 kN/m3

Yes

Air voids after

compaction

5% No No Yes Yes

Water content

less than plastic

limit of the soil

Do not pass the end product

specifications.

Yes Yes

Permeability

1.5x10-9

2.83 x10-10

Yes

4.55 x10-10

Yes

Not prone to

shrink or swell

(activity)

0.94 (Normal)

Yes

0.51 (Inactive)

Yes

Constant Shear

strength withchanges to

water content

263.81kPa 255.33kPa


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Plasticity index 24% 33%

Soil NameChina and

Bentonite clayChina clay Silty clay Clayey silt

Only two soils meet all the requirements, but the Clayey Silt has the highest value of Shear

Strength, therefore it is the selected soil for the construction of the Low Permeability Blanket.

5 References1 Barnes, G.E., 2010. Soil Mechanics Principles and Practice (Third Edition). Basingstoke:

Palgrave Macmillan

2 Craig, R.F., 2004. Soil Mechanics (Seventh Edition). London: E & FN Spon3 Geotest,2010, Soil tests, Available http://www.geotechdata.info/geotest, (Accessed

20/02/2012)

4 Murthy, V.N.S,2002. Geotechnical Engineering: Principles and Practices of Soil Mechanicsand Foundation Engineering.(First Edition CRC Press

5 Sidhu, I., 2010. An Investigation into the Undrained Shear Strength of Cohesive Materials.London: Brunel University of West London.

6 Toll, 2008, Unsaturated Soils: Advances in Geo Engineering, (First edition), CRC Press7 University of West England, Soil properties, Available

http://environment.uwe.ac.uk/geocal/SoilMech/classification/soilclas.htm (Accessed

23/02/2012

8 Unknown Author (2004) Correlations Between Soil Plasticity and Strength Parameters,Available through

http://web.mst.edu/~rogersda/umrcourses/ge441/Soil%20Plasticity%20vs%20Strength%20P

arameters.pdf, (Accessed 25/02/2012)

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