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1

ENEN20002 Earth Processes for Engineering

Laboratory report

Nikola Tastanoski

766492

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Table of Contents

ABSTRACT ......................................................................................................................... 3

INTRODUCTION ................................................................................................................. 4

AIM ................................................................................................................................... 5

METHODS OF CLASSIFYING AND IDENTIFYING BH1, BH2 AND BH3 .................................... 5

VISUAL CLASSIFICATION ............................................................................................................. 5

BH1 ................................................................................................................................................ 5

BH2 ................................................................................................................................................ 5

BH3 ................................................................................................................................................ 5

GRAIN SIZE DISTRIBUTION .......................................................................................................... 6

ATTERBERG LIMITS ..................................................................................................................... 7

LIQUID LIMIT .................................................................................................................................. 7

PLASTIC LIMIT ................................................................................................................................ 8

EART DAM ......................................................................................................................... 9

STABILITY ZONE .......................................................................................................................... 9

CORE ZONE ............................................................................................................................... 10

FILTER ZONE ............................................................................................................................. 10

PROPOSED CONSTRACTION SOILS ............................................................................................ 10

CONCLUSION ................................................................................................................... 10

APPENDEX ....................................................................................................................... 11

REFERENCE ...................................................................................................................... 14

3

ABSTRACT

A laboratory study has been done over 3 soil samples taken from three different borehole

locations in order to assess the soil properties and suitability for building an earth dam.

Visual classification, grain size limits, plasticity, liquid limit, plastic limit and atterberg limits

tests has been conducted over the soil samples.

KEYWORDS: plasticity, liquid limit, borehole, soil, atterberg limits, LL, grain size

4

INTRODUCTION

A constructing firm named “Sustainable Earth” has been commissioned to conduct a feasible

study for a project that includes the construction of an earth dam. The project team was

required to assess three samples taken from three different borehole locations (Figure 1).

These samples have been collected for further investigation and classification in order to

assess the properties and suitability for constructing the earth dam (Practical exercise, 2016).

Figure 1 Map displaying the three borehole locations

Figure 2 visually displays the proposed cross-section structure of the earth dam, which is

divided in three different zones.

1. Stability zone

2. Core zone

3. Filter zone

Figure 2 Cross section of the earth dam

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AIM

The Aim of this report is to analyse and discover the best suited soil for each zone of the earth

dam, after performing analysis on three different soil samples BH1, BH2 and BH3 taken from

three different locations on the site.

METHODS OF CLASSIFYING AND IDENTIFYING BH1, BH2 AND BH3

VISUAL CLASSIFICATION

In the process of visual classification of the three samples, the Unified soil classification chart

(used as USCC in text) (Check Appendix) has been used in order to visually asses and classify

the soil samples.

All three soils had different colour. Also the grain size was visible with naked eye, which means

they were bigger than 0.075 mm.

BH number Dry strength

(crushing or not)

Latency Toughness

BH1 N/a N/a N/a

BH2 Light to medium MH Quick to slow ML Slight to medium

BH3 Medium to high CI Slow to none MH High

Figure 3. Visual classification data

BH1

A visual classification has been performed over BH1. It had yellowish colour with a dry-sandy

structure. The grain size was a mixture of small and big particles with size not exciding 0.1

mm. In contact with water, it doesn’t react, in other words it does not absorb water.

According to USCC BH1 is SP, poorly graded ands, gravely sands, little or no fines.

BH2

During the visual classification of BH2 it has been noticed that it is dry with light brown colour.

Its structure was mainly fine with minimal course in it. In contact with water it reacts and

absorbs it. It had light strength which was confirmed by breaking small piece between two

fingers using extremely small amount of force.

According to USCC BH2 is described as OH, Organic clays of medium to high plasticity.

BH3

On the visual classification it has been determined that it has brown colour. In contact with

water it absorbs it and it has fine structure with minimal course in it which is more rough than

BH2. Under dry conditions it is harder to break than BH2.

Using USCC BH3 is classified as SM, silty sands, poorly graded sand- silt mixtures.

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GRAIN SIZE DISTRIBUTION

Results for Sieve analysis of sample collected from BH1

Sample size: 510 gm

Figure 4 Sieve analysis data

Mass retained = mass of sieve + soil retained minus mass of sieve

Percent retained= !\"#\"$%&\'() #%++ ,)&%\'-).

/01 '∗' 100

Percent finder = 100- percent retained

Figure 5 Grain size distribution D10 (blue, D30 (red) and D60 (Yellow)

Cc (Coefficient of curvature) and Cu (Coefficient of uniformity) are measurements of gradation of any

Sieve

Aperture

Mass of Sieve

+ soil retained

Mass of

Sieve

Mass

retained

Cumulative

Mass

retained

Percent

retained

Percent

finer

[mm] [gm] [gm] [gm] [gm] [%] [%]

4.75 559.31 559.31 0 0 0 100

2.36 554.5 534.29 20.21 20.21 3.96 96.04

1.18 670.75 509.55 161.2 181.41 35.57 64.43

0.6 737.87 473.65 264.22 445.63 87.38 12.62

0.3 485.64 432.34 53.3 498.93 97.83 2.17

0.15 419.55 410.74 8.81 507.74 99.56 0.44

0.075 412.66 411.74 0.92 508.66 99.74 0.26

Pan 395.21 395.11 0.1

Total 508.76 99.76 0.24

mass 4235.49 3726.73 508.76

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soil samples

According to the Unifies Soil Classification System

- Well graded gravel GW has Cu>4 and 1<Cc<3

- Poorly graded soil GP is considered if the above conditions are not met

- Well graded sand SW has Cu≥6 and 1<Cc<3

- Poorly graded sands SP occurs if both conditions are not met.

Cc = 56178

591'∗'501

Cu = 591

501

D10=0.6 mm

D30=0.8 mm

D60=1.1 mm

After plugging in this data in the equations above we get that BH1 is a SP, poorly gadded sand

due to not meeting the criteria for Cu to be bigger than 4.

ATTERBERG LIMITS

Results for Atterberg limit tests of sample collected from BH3:

LIQUID LIMIT

Test number 1 2 3 4

No of Blow 43 30 28 19

Container number C#15 C#14 C#22 C#13

Mass of Container + wet soil[gm] 86.12 89.71 71.01 102.02

Mass of Container + dry soil[gm] 80.16 84.11 63.31 88.99

Mass of Container[gm] 61.6 72.67 49.41 68.59

Mass of Wet soil 24.52 17.04 21.6 33.43

Mass of Dry soil 18.56 11.44 13.9 20.4

Mass of water 5.96 5.6 7.7 13.03

Moisture content(%) 24.31 32.86 35.65 38.98

Figure 6 Atterberg limits data

Moisture content = :;++ <= >%&),

:%++ <= .,? +<\'$ '∗' 100

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Figure 7 Liquid limit results

Liquid limit of BH3 is 32.95

PLASTIC LIMIT

Test number 1 2 3

Container number D#31 D#34 D#39

Mass of Container + wet soil [gm] 17.02 16.46 16.34

Mass of Container + dry soil[gm] 16.76 16.23 16.17

Mass of Container[gm] 15.22 14.82 15.04

Mass of Wet soil 1.8 1.64 1.3

Mass of Dry soil 1.54 1.41 1.13

Mass of water 0.26 0.23 0.17

Moisture content (%) 14.44 14.02 13.08

Figure 8 Plastic limit results

Moisture content = :%++ <= >%&),

:%++ <= .,? +<\'$ '∗' 100

Plastic limit for BH3 is 13.95

Plasticity index is the difference between liquid limit and plastic limit.

PI=LL-PL=33-14=19

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Figure 9 Plasticity chart

According to the chart above and the data obtained from the laboratory practical, BH3 sits in

the CL area.

EART DAM

STABILITY ZONE

Figure 10 Cross section of the Earth dam

Stability zone occupies the biggest part of the earth dam, divided into upstream and

downstream slopes. It covers the core zone and protects it from cracks and drainage. Both

slopes have to protect the core zone from waves, pressure and drainage.

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CORE ZONE

It is located in the centre of the dam where it provides stability, water tightness and adequate

shear resistance. Because of its role, the core zone has to be made of the tightest soil. The

soil shouldn’t contain much organic content I order to minimise the swelling and change in

volume.

FILTER ZONE

The filter zone controls the seepage water, allowing it to flow through it by reducing the

pressure in the dam and making it more stable. The horizontal filter helps in rapid

consolidation, while the vertical one is placed along the horizontal due to becoming inefficient

under large scale of stratification. The desired soil for this part of the dam is the one with

bigger particles in it.

PROPOSED CONSTRACTION SOILS

BH1 for the core zone

BH2 for the filter zone

BH3 for the stability zone

CONCLUSION

Visual classification, atterberg limits tests and grain size distribution analysis test have been

performed over three different samples of soils and using the United Soil Classification System

we’ve been able to classify the samples and determine their properties, to be able to

determine which, one should be used in constructing each part of the earth dam. From the

results it has been concluded that BH1 is suitable for the core zone, BH2 for the filter zone

and BH3 for the stability zone.

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APPENDEX

BH number Dry strength

(crushing or not)

Latency Toughness

BH1 N/a N/a N/a

BH2 Light to medium MH Quick to slow ML Slight to medium

BH3 Medium to high CI Slow to none MH High

Figure 3. Visual classification data

Figure 4 Sieve analysis data

Figure 5 Grain size distribution D10 (blue, D30 (red) and D60 (Yellow)

Sieve

Aperture

Mass of Sieve

+ soil retained

Mass of

Sieve

Mass

retained

Cumulative

Mass

retained

Percent

retained

Percent

finer

[mm] [gm] [gm] [gm] [gm] [%] [%]

4.75 559.31 559.31 0 0 0 100

2.36 554.5 534.29 20.21 20.21 3.96 96.04

1.18 670.75 509.55 161.2 181.41 35.57 64.43

0.6 737.87 473.65 264.22 445.63 87.38 12.62

0.3 485.64 432.34 53.3 498.93 97.83 2.17

0.15 419.55 410.74 8.81 507.74 99.56 0.44

0.075 412.66 411.74 0.92 508.66 99.74 0.26

Pan 395.21 395.11 0.1

Total 508.76 99.76 0.24

mass 4235.49 3726.73 508.76

12

Test number 1 2 3 4

No of Blow 43 30 28 19

Container number C#15 C#14 C#22 C#13

Mass of Container + wet soil[gm] 86.12 89.71 71.01 102.02

Mass of Container + dry soil[gm] 80.16 84.11 63.31 88.99

Mass of Container[gm] 61.6 72.67 49.41 68.59

Mass of Wet soil 24.52 17.04 21.6 33.43

Mass of Dry soil 18.56 11.44 13.9 20.4

Mass of water 5.96 5.6 7.7 13.03

Moisture content(%) 24.31 32.86 35.65 38.98

Figure 6 Atterberg limits data

Figure 7 Liquid limit results

Test number 1 2 3

Container number D#31 D#34 D#39

Mass of Container + wet soil [gm] 17.02 16.46 16.34

Mass of Container + dry soil[gm] 16.76 16.23 16.17

Mass of Container[gm] 15.22 14.82 15.04

Mass of Wet soil 1.8 1.64 1.3

Mass of Dry soil 1.54 1.41 1.13

Mass of water 0.26 0.23 0.17

Moisture content (%) 14.44 14.02 13.08

Figure 8 Plastic limit results

13

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REFERENCE

Mishra G. 2016. DESIGN PRINCIPLES OF EARTH DAMS. [ONLINE] Available at:

http://theconstructor.org/water-resources/design-principles-of-earth-dams/9469/. [Accessed

14 October 2016].

Mishra, G. (2013). EARTHFILL DAMS & ITS CLASSIFICATION. The Constructor. Available at

http://theconstructor.org/water-resources/earthfill-dams-its-classification/2273/ [ Accessed

14 October 2016].

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