Study of Geotechnical properties of black cotton soil
contaminated by castor oil and stabilization of contaminated soil
by sawdust
Ms. Arpita V PatelAsst. Professor, Department of Civil
Engineering,
Parul Institute of Engineering and Technology, Waghodia,
Vadodara.E-mail ID: [email protected]
Abstract:The environment is being polluted by humans & in
doing so,
not only air & water but land is also being contaminated.
The major contaminant of soil is oil. These contaminations largely
affect the geotechnical properties of soil, specially physical
&chemical. Taking into consideration the structural safety of
structures of such location it is necessary to consider the change
in the geotechnical properties due to such contaminations. In this
paper the changes in the geotechnical properties like plastic
limit, liquid limit, specific gravity, optimum moisture content,
maximum dry density, cohesion, angle of internal friction, and
California bearing ratio ofblack cotton soil with 5%, 10% and 15%
castor oil as contaminant is represented. After that the effect of
sawdust as stabilizer on black cotton soil contaminated with 10%
castor oil is observed.
Keywords: plastic limit, liquid limit, specific Gravity, optimum
moisture content, maximum dry density, cohesion, angle of internal
friction, California bearing ratio, castor oil,contamination,
sawdust, stabilize
1. Introduction
Rapid increase in the population all over the world is directly
proportional to the development programmers in housing and
construction for industrial enhancement. Nowadays it can be shown
that geotechnical work and earning are directly related to the
industrialization that in turn brings pollution effect to the
surrounding. The rapid growth of industrialization has created
several problems in all parts of the world. In the present
situation, if industrial development for the benefit of humanity is
not properly planned then environment is being adversely affected
at a great speed. Increasing of industrialization and changes in
land use pattern have resulted in general degradation of the soil
i.e. pollution of soil, water and air which affect the technology
of the environment area and vice versa.
Oil contaminated soil is defined as any earthen material or
artificial fill that has human or natural alteration in its
physical, chemical, biological or radiological integrity resulting
from the introduction of crude oil, any fraction or derivative
there of (such as gasoline, diesel, or Motor oil) or oil based
product.
Oil contamination of soils may occur through a variety of
sources such as oil leakage from damaged pipelines, tanker
accidents, and discharge from coastal facilities or natural
seepage. One typical example is the oil spills in Kuwait during the
Gulf war. Another example is the oil spill at Valdez, Alaska
resulting from an oil tanker accident. In Saudi Arabia, soil is
being contaminated by the leakage of oil from damagedpipelines and
oil storage tanks. Despite the best efforts of both, petroleum
industry and regulatory community releases, leakages and spills of
petroleum products occurs frequently. It is estimated that in the
United States, 25% of the storage of petroleum products are
leaking. Once a spill or leakage occurs, the hydrocarbon liquid
under gravity moves down to the groundwater partially and upon
reaching the ground water table, this liquid may spread
horizontally by migration within the capillary zone, thereby
further saturating the soil. Clay particles are chemically active
soil particles. Their behavior is always affected by the
environment to variable degree depending on the clay particles
mineralogy. The particular environment includes the pore fluids,
their properties and type of ions present therein. Their behavior
can be altered substantially by the presence or permeation of
different pore fluids. Nowadays castor oil is also used in
industries like in the manufacturing of soaps, plastics, synthetic
resins, fibers, paints, varnishes, lubricants, dyes, leather
treatments, grease, hydraulic fluids, machining oils, rubbers and
as bio fuel. Due to these all uses, it may contaminate soil. Due to
soil contamination by various liquids from different sources, clay
behavior may change.Most foundation design and construction is
based on ASTM or Indian standards, in which distilled water is a
standard control pore fluid at room temperature. Since many
underground soil/water systems are polluted to some degree, some
difference in soil properties exists in laboratory and in site
conditions. Therefore certain analysis and design procedures for
foundation structures must be revised or modified. Most foundation
structures require friction or adhesive force between structure and
soil for earth pressure, pile capacity and bearing capacity
compaction. Unfortunately this force changes frequently if the
groundwater table fluctuates.
The present study shows the interaction behavior of typical CH
type black cotton soil and castor oil. To study the interaction
effects, the soil has been tested with varying percentage of oil.
The physical and engineering properties of virgin soils and
contaminated soils were determined.
13-14 May 2011 B.V.M. Engineering College,
V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering &
Technology
2. Materials & Methods
2.1 Materials:
The experimental work was conducted with Black cotton soil,
procured from Karajan, Gujarat. Castor oil was used as contaminant
and sawdust as stabilizer. The soil was contaminated in the
laboratory with varying percentage of castor oil as contaminant to
study the contaminant’s effect on various geotechnical properties
of soils.
2.2 Procedure of Contamination:Initially, the soil is air dried
and hand sorted to remove the pebbles and vegetable matter, if any.
It is then oven dried, ground, pulverized and sieved through a 425μ
sieve. The soil is then contaminated by castor oil in varying
percentage i.e. 5%, 10% and 15% by weights and tested to determine
their physical and engineering properties. After that black cotton
soil contaminated with 10% castor oil is stabilized with sawdust.
The sawdust is mixed with contaminated soil in varying percentages,
i.e. 2.5%, 5%, 7.5% &10% by weights.The aim of the
investigation is to examine the effect of contaminant and
stabilizer on various geotechnical properties of soil. Following
laboratory tests have been performed to study the geotechnical
properties of soil before and after contamination.Physical and
Engineering properties
- Atterberg’s Limits- Maximum Dry density and optimum
moisture
content- Specific gravity- Strength test- CBR test
2.3 Experimental WorkThe experimental schedule for collecting
data is shown in the following tables.
Table 1: Test performed on Black cotton Soil
Contaminated soilTest Black
cotton Soil
C5 C10 C15Atterberg Limit √ √ √ √
M.D.D √ √ √ √
O.M.C √ √ √ √
Specific gravity √ √ √ √
U.C.S √ √ √ √
Triaxial Test √ √ √ √
C.B.R test √ √ √ √
C=Castor Oil, Suffix is percentage of contamination
Table 2: work schedule for finding out effect of sawdust as
stabilizer on Black cotton soil contaminated with 10% castor
oil
Contaminated soil for stabilization (saw Dust)2.5% 5% 7.5%
10%
No. of Days No. of Days No. of Days No. of Days
Test
1 3 7 14 1 3 7 14 1 3 7 14 1 3 7 14UCS √ √ √ √ √ √ √ √ √ √ √ √ √
√ √ √Triaxial
√ √ √ √
CBR √ √ √ √
Here, No. of Days is days after mixing sawdust with contaminated
soil
3. Result & Discussion
3.1 Result:
The effect of castor oil contamination on geotechnical
properties of black cotton soil is shown in table 3 & effect of
stabilizer on geotechnical properties of black cotton soil
contaminated with 10% castor oil is shown in table 4.
Table 3: Various Geotechnical Properties of virgin black cotton
soil and contaminated black cotton soil
Contaminated black cotton soilProperties of soil
Virgin Black cotton
soilC5 C10 C15
Specific Gravity 2.58 2.14 1.99 1.97
Liquid Limit(%) 77.14 72.43 69.28 56.49
Plastic Limit (%) 38.55 37.99 36.22 33
Maximum Dry Density(gm/cc)
1.59 1.55 1.52 1.68
Optimum Moisture content (%)
20.5 16.91 14.36 7.19
Unconfined Compressive Strength
(kg/cm2)1.19 0.62 0.61 0.36
Cohesion (kg/cm2) 1.42 0.84 0.6 0.46
Angle of internal friction (Deg.)
3.08 11.18 11.49 12.95
CBR (Unsoaked) 17.83 21.34 20.77 18.53
CBR (soaked) 3.09 1.12 1.03 1.68
13-14 May 2011 B.V.M. Engineering College,
V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering &
Technology
Table 4: Effect of saw dust on engineering properties of black
cotton soil contaminated with 10% castor oil
Percentage of saw dust
Properties of soil
No. of day for aging period
Contaminated soil
2.5%
5%7.5%
10%
1 0.61 1.02 1.83 3.07 2.583 0.61 1.03 2.43 3.12 2.927 0.61 1.39
2.49 3.45 3.29
UnconfinedCompressive
Strength (kg/cm2) 14 0.61 1.73 3.03 4.17 3.96Cohesion
(kg/cm2)
14 0.6 0.52 1.2 0.53 0.14
Angle of internal friction (Degree)
14 12.9 25.8 16.1 25.9 34.6
CBR Value (Unsoaked)
1 20.77 15.3 10.1 17.1 24.7
CBR Value (soaked)
1 1.03 1.4 0.37 1.26 1.12
0.61 0.61 0.61 0.61
1.02 1.03
1.39
1.731.83
2.43 2.49
3.033.073.12
3.45
4.17
2.58
2.92
3.29
3.96
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
1 3 7 14
Aging period of stabilization (days)
Un
con
fin
ed c
om
pre
ssiv
e st
ren
gth
(k
g/c
m2)
Black cotton soilcontaminated with 10%castor oil
Black cotton soilcontaminated with 10%castor oil +2.5%
sawdust
Black cotton soilcontaminated with 10%castor oil +5% sawdust
Black cotton soilcontaminated with 10%castor oil +7.5%
sawdust
Black cotton soilcontaminated with 10%castor oil +10%
sawdust
Fig. 1 Effect of Sawdust on unconfined compressive strength of
black cotton soil contaminated with 10% custor Oil
Fig. 2 Effect of Sawdust on Cohesion and angle of internal
friiction of Black cotton soil contaminated with 10% custor oil
Fig. 3 Effect of Sawdust on CBR value (Soaked and Unsoaked) of
Black cotton soil contaminated with 10% custor oil
3.2 Discussion:The specific gravity, Liquid limit, plastic limit
and optimum moisture content of black cotton soil were observed to
be decreasing with increase in percentage of contaminant. For black
cotton soil contaminated with 5% and 10% castor oil, the maximum
dry density was found less than that of virgin soil and for 15%
contaminant, it was found more than that of virgin soil. The
unconfined compressive strength and cohesion of contaminated black
cotton soil decrease as percentage of contaminant increases while
angle of internal friction was
20.77
1.03
15.3
1.4
10.1
0.37
17.1
1.26
24.7
1.12
0
5
10
15
20
25
30
CBR Value (Unsoaked) CBR Value (soaked)
Aging Period of stabilitation (1day)
Values
Black cotton soil contaminated with10% castor oil
Black cotton soil contaminated with10% castor oil +2.5%
sawdust
Black cotton soil contaminated with10% castor oil +5%
sawdust
Black cotton soil contaminated with10% castor oil +7.5%
sawdust
Black cotton soil contaminated with10% castor oil +10%
sawdust
0.6
12.9
0.52
25.8
1.2
16.1
0.53
25.9
0.14
34.6
0
5
10
15
20
25
30
35
40
Cohesion (kg/cm2) Angle of internal friction(Degree)
Aging period of stabilization (14days)
values
Black cotton soil contaminated with10% castor oil
Black cotton soil contaminated with10% castor oil +2.5%
sawdust
Black cotton soil contaminated with10% castor oil +5%
sawdust
Black cotton soil contaminated with10% castor oil +7.5%
sawdust
Black cotton soil contaminated with10% castor oil +10%
sawdust
13-14 May 2011 B.V.M. Engineering College,
V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering &
Technology
observed to be increasing as percentage of contaminant
increased. The CBR value (soaked & unsoaked) was seen to be
decreasing as percentage of contaminant increased but unsoaked CBR
values are found greater than that of virgin soil.
The Unconfined compressive strength (UCS) of stabilized black
cotton soil contaminated with 10% castor oil increased by 67.21% at
1st day, 68.85% at 3rd day, 128.4% at 7th day and 183.31% at 14th
day with 2.5% stabilizer. It increased by 199.36% at 1st day,
298.57% at 3rd day, 308.5% at 7th day and 396.38% at 14th day with
5% stabilizer. It (UCS) found to increase by 403.41% at 1st day
411.47% at 3rd day, 465.57% at 7th day and 583.6% at 14th day with
7.5% stabilizer. It (UCS)increased by 322.76% at 1st day, 378.68%
at 3rd day, 440.08% at 7th day and 549.18% at 14th day with 10%
stabilizer.The cohesion of stabilized black cotton soil
contaminated with 10%castor oil found to decreased by 13.10% with
2.5% stabilizer, increased by 99.83% with 5% stabilizer, decreased
by 12.93% and 77.44% with 7.5% and10% stabilizer respectively. The
angle of internal friction of stabilized soil increased by 99.38%,
24.63%, 100.38% and 167.87% with 2.5%, 5%, 7.5%, and 10% stabilizer
respectively.The CBR value (unsoaked) of stabilized soil decreased
by 51.33%, 26.06%, 17.29% and 18.9% with 2.5%, 5%, 7.5% and 10%
stabilizer respectively.The CBR value (soaked) of stabilized soil
decreased by
64.05% with 2.5% stabilizer, while increased by 8.8%, 22.72% and
36% with 5%, 7.5% and 10% stabilizer respectively.
4. Conclusion
4.1Effect of contaminant:The geotechnical properties of black
cotton soil found to be greatly affected by 15% castor oil among
the various percentage of contaminant.
4.2 Effect of stabilizer (sawdust) on contaminated soil: The
unconfined compressive strength of stabilized soil increases as the
time duration increases. The maximum unconfined compressive
strength found on the 14th day with 7.5% sawdust. The angle of
internal friction was found in an irregular pattern. The cohesion
was found maximum with 5% sawdust and minimum with 10% sawdust. The
maximum unsoaked CBR value of stabilized soils found with 10%
sawdust, while minimum with 5%. The maximum soaked CBR value of
stabilized soils found with 2.5% sawdust, while minimum with 5%
sawdust.
References:A. Fotinich, V.K.Dhir, and S. Lingineni
(January-1999)”Remediation of simulated soils contaminated with
Diesel”, Journal of Enviornmental engineering, p.g 36-45
Hasan A. Al-sanad,Walid K-Eid and Nabil F-Ismael (may-1995)
“Geotechnical Properties of Oil Contaminated Kuwaiti Sand” ASCE
Journal of Geotechnical Engineering p.g.407-415
Hasan A. Al-sanad and Nabil F-Ismael (march-1997 “Agining Effect
on Oil Contaminated Kuwaiti Sand” ASCE Journal of Geotechnical and
Geoenvironmental Engineering p.g.290-293
Jay N.Meegoda (January 1999) “ Stabilization / Solidification of
Petroleum contaminated Soils with Asphalt Emulsions” Practice
Periodical of Hazardous, Toxin, and Radioactive Waste Management
p.g.46-55
Sanjay J shah, A.V.Shroff, Jignesh V Patel, K.C. Tiwari, D
Ramakrishanan (2003) “stabilization of Fuel Oil Contaminated Soil-A
Case Study” Geotechnical and Geological Engineering, p.g.415-427P
Tiwari, M.K. Gupta and R.K Srivastava (2006) “Laboratory Studies on
Surfactant Enhanced Remediation of Engine Oil Contaminated Soils”,
Indian Geotechnical Journal 36(4), p.g. 287-298
13-14 May 2011 B.V.M. Engineering College,
V.V.Nagar,Gujarat,India
National Conference on Recent Trends in Engineering &
Technology
Study of Geotechnical properties of black cotton soil
contaminated by castor oil and stabilization of contaminated soil
by sawdust
Ms. Arpita V Patel
Asst. Professor, Department of Civil Engineering,
Parul Institute of Engineering and Technology, Waghodia,
Vadodara.
E-mail ID: [email protected]
Abstract:
The environment is being polluted by humans & in doing so,
not only air & water but land is also being contaminated. The
major contaminant of soil is oil. These contaminations largely
affect the geotechnical properties of soil, specially physical
& chemical. Taking into consideration the structural safety of
structures of such location it is necessary to consider the change
in the geotechnical properties due to such contaminations. In this
paper the changes in the geotechnical properties like plastic
limit, liquid limit, specific gravity, optimum moisture content,
maximum dry density, cohesion, angle of internal friction, and
California bearing ratio of black cotton soil with 5%, 10% and 15%
castor oil as contaminant is represented. After that the effect of
sawdust as stabilizer on black cotton soil contaminated with 10%
castor oil is observed.
Keywords: plastic limit, liquid limit, specific Gravity, optimum
moisture content, maximum dry density, cohesion, angle of internal
friction, California bearing ratio, castor oil, contamination,
sawdust, stabilize
1. Introduction
Rapid increase in the population all over the world is directly
proportional to the development programmers in housing and
construction for industrial enhancement. Nowadays it can be shown
that geotechnical work and earning are directly related to the
industrialization that in turn brings pollution effect to the
surrounding. The rapid growth of industrialization has created
several problems in all parts of the world. In the present
situation, if industrial development for the benefit of humanity is
not properly planned then environment is being adversely affected
at a great speed. Increasing of industrialization and changes in
land use pattern have resulted in general degradation of the soil
i.e. pollution of soil, water and air which affect the technology
of the environment area and vice versa.
Oil contaminated soil is defined as any earthen material or
artificial fill that has human or natural alteration in its
physical, chemical, biological or radiological integrity resulting
from the introduction of crude oil, any fraction or derivative
there of (such as gasoline, diesel, or Motor oil) or oil based
product.
Oil contamination of soils may occur through a variety of
sources such as oil leakage from damaged pipelines, tanker
accidents, and discharge from coastal facilities or natural
seepage. One typical example is the oil spills in Kuwait during the
Gulf war. Another example is the oil spill at Valdez, Alaska
resulting from an oil tanker accident. In Saudi Arabia, soil is
being contaminated by the leakage of oil from damaged pipelines and
oil storage tanks. Despite the best efforts of both, petroleum
industry and regulatory community releases, leakages and spills of
petroleum products occurs frequently. It is estimated that in the
United States, 25% of the storage of petroleum products are
leaking. Once a spill or leakage occurs, the hydrocarbon liquid
under gravity moves down to the groundwater partially and upon
reaching the ground water table, this liquid may spread
horizontally by migration within the capillary zone, thereby
further saturating the soil. Clay particles are chemically active
soil particles. Their behavior is always affected by the
environment to variable degree depending on the clay particles
mineralogy. The particular environment includes the pore fluids,
their properties and type of ions present therein. Their behavior
can be altered substantially by the presence or permeation of
different pore fluids. Nowadays castor oil is also used in
industries like in the manufacturing of soaps, plastics, synthetic
resins, fibers, paints, varnishes, lubricants, dyes, leather
treatments, grease, hydraulic fluids, machining oils, rubbers and
as bio fuel. Due to these all uses, it may contaminate soil. Due to
soil contamination by various liquids from different sources, clay
behavior may change.
Most foundation design and construction is based on ASTM or
Indian standards, in which distilled water is a standard control
pore fluid at room temperature. Since many underground soil/water
systems are polluted to some degree, some difference in soil
properties exists in laboratory and in site conditions. Therefore
certain analysis and design procedures for foundation structures
must be revised or modified. Most foundation structures require
friction or adhesive force between structure and soil for earth
pressure, pile capacity and bearing capacity compaction.
Unfortunately this force changes frequently if the groundwater
table fluctuates.
The present study shows the interaction behavior of typical CH
type black cotton soil and castor oil. To study the interaction
effects, the soil has been tested with varying percentage of oil.
The physical and engineering properties of virgin soils and
contaminated soils were determined.
2. Materials & Methods
2.1 Materials:
The experimental work was conducted with Black cotton soil,
procured from Karajan, Gujarat. Castor oil was used as contaminant
and sawdust as stabilizer. The soil was contaminated in the
laboratory with varying percentage of castor oil as contaminant to
study the contaminant’s effect on various geotechnical properties
of soils.
2.2 Procedure of Contamination:
Initially, the soil is air dried and hand sorted to remove the
pebbles and vegetable matter, if any. It is then oven dried,
ground, pulverized and sieved through a 425μ sieve. The soil is
then contaminated by castor oil in varying percentage i.e. 5%, 10%
and 15% by weights and tested to determine their physical and
engineering properties. After that black cotton soil contaminated
with 10% castor oil is stabilized with sawdust. The sawdust is
mixed with contaminated soil in varying percentages, i.e. 2.5%, 5%,
7.5% &10% by weights.
The aim of the investigation is to examine the effect of
contaminant and stabilizer on various geotechnical properties of
soil. Following laboratory tests have been performed to study the
geotechnical properties of soil before and after contamination.
Physical and Engineering properties
· Atterberg’s Limits
· Maximum Dry density and optimum moisture content
· Specific gravity
· Strength test
· CBR test
2.3 Experimental Work
The experimental schedule for collecting data is shown in the
following tables.
Table 1: Test performed on Black cotton Soil
Test
Black cotton Soil
Contaminated soil
C5
C10
C15
Atterberg Limit
√
√
√
√
M.D.D
√
√
√
√
O.M.C
√
√
√
√
Specific gravity
√
√
√
√
U.C.S
√
√
√
√
Triaxial Test
√
√
√
√
C.B.R test
√
√
√
√
C=Castor Oil, Suffix is percentage of contamination
Table 2: work schedule for finding out effect of sawdust as
stabilizer on Black cotton soil contaminated with 10% castor
oil
Test
Contaminated soil for stabilization (saw Dust)
2.5%
5%
7.5%
10%
No. of Days
No. of Days
No. of Days
No. of Days
1
3
7
14
1
3
7
14
1
3
7
14
1
3
7
14
UCS
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
√
Triaxial
√
√
√
√
CBR
√
√
√
√
Here, No. of Days is days after mixing sawdust with contaminated
soil
3. Result & Discussion
3.1 Result:
The effect of castor oil contamination on geotechnical
properties of black cotton soil is shown in table 3 & effect of
stabilizer on geotechnical properties of black cotton soil
contaminated with 10% castor oil is shown in table 4.
Table 3: Various Geotechnical Properties of virgin black cotton
soil and contaminated black cotton soil
Properties of soil
Virgin Black cotton soil
Contaminated black cotton soil
C5
C10
C15
Specific Gravity
2.58
2.14
1.99
1.97
Liquid Limit(%)
77.14
72.43
69.28
56.49
Plastic Limit (%)
38.55
37.99
36.22
33
Maximum Dry Density(gm/cc)
1.59
1.55
1.52
1.68
Optimum Moisture content (%)
20.5
16.91
14.36
7.19
Unconfined Compressive Strength (kg/cm2)
1.19
0.62
0.61
0.36
Cohesion (kg/cm2)
1.42
0.84
0.6
0.46
Angle of internal friction (Deg.)
3.08
11.18
11.49
12.95
CBR (Unsoaked)
17.83
21.34
20.77
18.53
CBR (soaked)
3.09
1.12
1.03
1.68
Table 4: Effect of saw dust on engineering properties of black
cotton soil contaminated with 10% castor oil
Properties of soil
No. of day for aging period
Contaminated soil
Percentage of saw dust
2.5%
5%
7.5%
10%
Unconfined Compressive Strength (kg/cm2)
1
0.61
1.02
1.83
3.07
2.58
3
0.61
1.03
2.43
3.12
2.92
7
0.61
1.39
2.49
3.45
3.29
14
0.61
1.73
3.03
4.17
3.96
Cohesion (kg/cm2)
14
0.6
0.52
1.2
0.53
0.14
Angle of internal friction (Degree)
14
12.9
25.8
16.1
25.9
34.6
CBR Value (Unsoaked)
1
20.77
15.3
10.1
17.1
24.7
CBR Value (soaked)
1
1.03
1.4
0.37
1.26
1.12
0.610.610.610.61
1.02
1.03
1.39
1.73
1.83
2.43
2.49
3.03
3.07
3.12
3.45
4.17
2.58
2.92
3.29
3.96
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
13714
Aging period of stabilization (days)
Unconfined compressive strength (kg/cm2)
Black cotton soil
contaminated with 10%
castor oil
Black cotton soil
contaminated with 10%
castor oil +2.5% sawdust
Black cotton soil
contaminated with 10%
castor oil +5% sawdust
Black cotton soil
contaminated with 10%
castor oil +7.5% sawdust
Black cotton soil
contaminated with 10%
castor oil +10% sawdust
Fig. 1 Effect of Sawdust on unconfined compressive strength of
black cotton soil contaminated with 10% custor Oil
SHAPE \* MERGEFORMAT
Fig. 2 Effect of Sawdust on Cohesion and angle of internal
friiction of Black cotton soil contaminated with 10% custor oil
Fig. 3 Effect of Sawdust on CBR value (Soaked and Unsoaked) of
Black cotton soil contaminated with 10% custor oil
3.2 Discussion:
The specific gravity, Liquid limit, plastic limit and optimum
moisture content of black cotton soil were observed to be
decreasing with increase in percentage of contaminant. For black
cotton soil contaminated with 5% and 10% castor oil, the maximum
dry density was found less than that of virgin soil and for 15%
contaminant, it was found more than that of virgin soil. The
unconfined compressive strength and cohesion of contaminated black
cotton soil decrease as percentage of contaminant increases while
angle of internal friction was observed to be increasing as
percentage of contaminant increased. The CBR value (soaked &
unsoaked) was seen to be decreasing as percentage of contaminant
increased but unsoaked CBR values are found greater than that of
virgin soil.
The Unconfined compressive strength (UCS) of stabilized black
cotton soil contaminated with 10% castor oil increased by 67.21% at
1st day, 68.85% at 3rd day, 128.4% at 7th day and 183.31% at 14th
day with 2.5% stabilizer. It increased by 199.36% at 1st day,
298.57% at 3rd day, 308.5% at 7th day and 396.38% at 14th day with
5% stabilizer. It (UCS) found to increase by 403.41% at 1st day
411.47% at 3rd day, 465.57% at 7th day and 583.6% at 14th day with
7.5% stabilizer. It (UCS) increased by 322.76% at 1st day, 378.68%
at 3rd day, 440.08% at 7th day and 549.18% at 14th day with 10%
stabilizer.
The cohesion of stabilized black cotton soil contaminated with
10%castor oil found to decreased by 13.10% with 2.5% stabilizer,
increased by 99.83% with 5% stabilizer, decreased by 12.93% and
77.44% with 7.5% and10% stabilizer respectively. The angle of
internal friction of stabilized soil increased by 99.38%, 24.63%,
100.38% and 167.87% with 2.5%, 5%, 7.5%, and 10% stabilizer
respectively.
The CBR value (unsoaked) of stabilized soil decreased by 51.33%,
26.06%, 17.29% and 18.9% with 2.5%, 5%, 7.5% and 10% stabilizer
respectively.
The CBR value (soaked) of stabilized soil decreased by 64.05%
with 2.5% stabilizer, while increased by 8.8%, 22.72% and 36% with
5%, 7.5% and 10% stabilizer respectively.
4. Conclusion
4.1Effect of contaminant:
The geotechnical properties of black cotton soil found to be
greatly affected by 15% castor oil among the various percentage of
contaminant.
4.2 Effect of stabilizer (sawdust) on contaminated soil:
The unconfined compressive strength of stabilized soil increases
as the time duration increases. The maximum unconfined compressive
strength found on the 14th day with 7.5% sawdust. The angle of
internal friction was found in an irregular pattern. The cohesion
was found maximum with 5% sawdust and minimum with 10% sawdust. The
maximum unsoaked CBR value of stabilized soils found with 10%
sawdust, while minimum with 5%. The maximum soaked CBR value of
stabilized soils found with 2.5% sawdust, while minimum with 5%
sawdust.
References:
A. Fotinich, V.K.Dhir, and S. Lingineni
(January-1999)”Remediation of simulated soils contaminated with
Diesel”, Journal of Enviornmental engineering, p.g 36-45
Hasan A. Al-sanad,Walid K-Eid and Nabil F-Ismael (may-1995)
“Geotechnical Properties of Oil Contaminated Kuwaiti Sand” ASCE
Journal of Geotechnical Engineering p.g.407-415
Hasan A. Al-sanad and Nabil F-Ismael (march-1997 “Agining Effect
on Oil Contaminated Kuwaiti Sand” ASCE Journal of Geotechnical and
Geoenvironmental Engineering p.g.290-293
Jay N.Meegoda (January 1999) “ Stabilization / Solidification of
Petroleum contaminated Soils with Asphalt Emulsions” Practice
Periodical of Hazardous, Toxin, and Radioactive Waste Management
p.g.46-55
Sanjay J shah, A.V.Shroff, Jignesh V Patel, K.C. Tiwari, D
Ramakrishanan (2003) “stabilization of Fuel Oil Contaminated Soil-A
Case Study” Geotechnical and Geological Engineering,
p.g.415-427
P Tiwari, M.K. Gupta and R.K Srivastava (2006) “Laboratory
Studies on Surfactant Enhanced Remediation of Engine Oil
Contaminated Soils”, Indian Geotechnical Journal 36(4), p.g.
287-298
0.6
12.9
0.52
25.8
1.2
16.1
0.53
25.9
0.14
34.6
0
5
10
15
20
25
30
35
40
Cohesion (kg/cm2)
Angle of internal friction
(Degree)
Aging period of stabilization (14days)
values
Black cotton soil contaminated with
10% castor oil
Black cotton soil contaminated with
10% castor oil +2.5% sawdust
Black cotton soil contaminated with
10% castor oil +5% sawdust
Black cotton soil contaminated with
10% castor oil +7.5% sawdust
Black cotton soil contaminated with
10% castor oil +10% sawdust
10% castor oil +10% sawdust
Black cotton soil contaminated with
10% castor oil +7.5% sawdust
Black cotton soil contaminated with
10% castor oil +5% sawdust
Black cotton soil contaminated with
10% castor oil +2.5% sawdust
Black cotton soil contaminated with
10% castor oil
Black cotton soil contaminated with
Values
Aging Period of stabilitation (1day)
CBR Value (soaked)
CBR Value (Unsoaked)
30
25
20
15
10
5
0
1.12
24.7
1.26
17.1
0.37
10.1
1.4
15.3
1.03
20.77