Upload
giovanni-kallika
View
228
Download
0
Embed Size (px)
Citation preview
8/2/2019 Lab Course Work
1/13
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)
8/2/2019 Lab Course Work
2/13
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
8/2/2019 Lab Course Work
3/13
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)
8/2/2019 Lab Course Work
4/13
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
8/2/2019 Lab Course Work
5/13
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.
8/2/2019 Lab Course Work
6/13
2
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
8/2/2019 Lab Course Work
7/13
3
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
8/2/2019 Lab Course Work
8/13
4
Index
8/2/2019 Lab Course Work
9/13
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
8/2/2019 Lab Course Work
10/13
6
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
8/2/2019 Lab Course Work
11/13
7
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
8/2/2019 Lab Course Work
12/13
8
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
8/2/2019 Lab Course Work
13/13
9
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)