Papers by Safa Hussain Abid Awn
Article history: Received 9 March 2021 Accepted 21 May 2021 Gets in the world at this time contin... more Article history: Received 9 March 2021 Accepted 21 May 2021 Gets in the world at this time continued growth and rapid development in the whole aspects of life. The urgent needing accomplished that is in civil engineering demands like the construction of houses, schools, hospitals, roads, and other structures. Because of that and for economic and security reasons; classifying soil and knowing its bearing capacity appeared to be very necessary conditions that offer a large domain of benefits that could not be counted. This study focused on classifying and determining the bearing capacity of some samples of soil that classified as soft soils of Baquba city the center of Diyala governorate in Iraq. Then trying to increase their bearing capacity. The California Bearing Ratio (CBR) was used in the paper to define soil strength because it is considered a force measuring parameter. Five elected physical and chemical treatments were used in predetermined percents taken from the literature an...
Key Engineering Materials
Soft clayey soils cover wide Iraqi areas specially the regions close to rivers and the southern p... more Soft clayey soils cover wide Iraqi areas specially the regions close to rivers and the southern part of this country Heavy weight structures like: highways, dams, multiple story buildings are suffering unacceptable settlement, when constructing on soft soils. The high contamination of water in such soils decrease the effective stress and reduce bearing capacity. The need was appeared to improve such problematic soil by the use of new technique of stone column treated with different percentages of natural bentonite by a series of field tests using full scale concrete footing constructed on soft soil in addition to a laboratory model to investigate settlement with time at constant stress. The soil that used in this study is natural clayey soil, brought from a location south of Diyala governorate, from a farm area. The study includes also: The effect of stone column diameter treated with bentonite on the behavior of footing constructing on soft clayey soil, The effect of stone column l...
IOP Conference Series: Earth and Environmental Science
Journal of Engineering and Sustainable Development
Natural soil is exposed, like other elements of the construction, to significant changes in tempe... more Natural soil is exposed, like other elements of the construction, to significant changes in temperatures are sources of forest fires or volcanic eruptions or natural bulky. Usually, accompanied by significant changes in temperatures of up to more than 300 degrees centigrade. Therefore, the need arises to study the effect of burning clayey soils, on the grain distribution and distribution of particleboard intricacies and atterbering limit and soil classification, in addition to the direct impact on the variables for the design of foundations such as the cohesion of the soil. The soil used was naturally clayey soil brought from Diyala province with (Liquid limit=56%, Plastic limit=51%, Specific gravity=2.59, the soil is classified as OH (Organic clays of medium to high plasticity). The soil was burned at different temperatures (75-150-300-600 ° C) using special oven for burning at high temperature, the study was directed to investigate the effect of repeat arson for each grade and study changes in soil properties and distribution particleboard and suitability of the construction. The study showed basic change in the particle distribution and Atterbering limits which means changing the engineering properties for the design of foundations construction which indicates the importance of this types of research and potential development to expand in this area and develop ways to put construction solutions for such cases. A reduction percent in plastic limit was 20% and 26% at the end of the fourth cycle at 300 o C and 150 o C respectively. Author Discoverd that the soil type changed from OH to MH after the first burning cycle at 75 o C. With the repetitive burning cycle, more changes on soil properties and type accrue. The soil is Ml after the fourth burning cycle at 75 o C.
Geotechnical Engineering Journal of SEAGS &AGSSEA, 2019
This paper presents the behavior of single tension pile in collapsible soil (Gypseous soil) by ex... more This paper presents the behavior of single tension pile in collapsible soil (Gypseous soil) by experimental work. The natural Gypseous soil with 66% gypsum used in the study was brought from Salah Al-Deen governorate in Iraq while that of the sand was brought from Karbalaa governorate, south of Baghdad, Iraq. The model pile used is smooth steel pipe pile with slenderness ratios (L/D) of 10, 15, 20 and 25. The effect of the gypsum content included in the soil as well as the effect of rest time and the effect of (L/D) on the pullout capacity of pile were studied in the laboratory scale model pile. The results showed that the pullout capacity of pile in Gypseous soil is more than its capacity in Sandy soil by about 64%. When the rest time was increased, the pullout capacity of tension pile embedded in Gypseous soil decreased. Increasing (L/D) ratio of pile in Gypseous soil from 15 to 20 increases pullout capacity of pile to about 65%, while increasing that ratio from 20 to 25 increases pullout capacity of pile to about 76% .
IEEE, 2018
Piles always used when the construction found on week or problematic soils. It also used for stru... more Piles always used when the construction found on week or problematic soils. It also used for structures which subject to tension load such as, tower, offshore structures, etc.
Due to the wide spread of the gypseous soil in the world in general form and especially in Iraq which reaches 70% in some regions. The problem of such soil appears at the first time of wetting it from any source and the soil become loose.
In the present study, we highlight on the investigation the behavior of steel pile in gypseous soil of 30%, and 60% gypsum content in both dry and soaking cases when subjected to pure tension load, and make a comparison between the pullout capacity of that pile when embedded in both type of gypseous soils. All tests of pile was conducted via used manufactured laboratory model which constructed specially for that purpose.
The gypseous soil used was brought from Salah Al-Deen governorate in Iraq, with 30%, and 60% gypsum content . The pile used is a solid steel with L/D equal to 10. The model was examined in a dry and soaking with water for 24 hour to show the effect of the presence of water on the pile capacity. Based on the result of the present study it can be recognize a substantial decrease in the pullout capacity of the pile of about 64%, and 68% after soaking of the soil-pile model for 24 hour with water for both gypseous soils of 30%, and 60% respectivily due to the dissolution of the gypsum content that related between the soil particles.
2
Which must be taken into consideration when constructing pile foundation on such collapsible soil. The results showed also that the pullout capacity of steel pile in gypseous soil of 60% gypsum content is more than that in gypseous soil of 30% gypsum content in both dry and soaking cases.
Civil Engineering Journal, 2019
As a matter of fact, the gypseous soil is usually considered as collapsible soil, such type of so... more As a matter of fact, the gypseous soil is usually considered as collapsible soil, such type of soil illustrates high resistance to settlement and high bearing capacity when it is dry, but it loses these characteristics when it is inundated and collapses excessively because of the sudden decrease in the volume of the surrounding soil mass. It is founded in the arid and semi-arid regions of the world in Asia, South Asia (Iraq, Syria, Jordan, Yemen, and Iran), North Africa, North America, moreover, it covers more than (31%) of the surface area in Iraq. Gypseous soil is one of the most difficult problems facing the process of building any project because of the difficulty of preventing leakage of water to the soil in practice. Deep foundation (piles) are one of the most common types used in collapsible soils which penetrating problematic soil layers and reaching more hard ones (end bearing piles) or transfers loads depending on skin friction (floating pile). The current work is directed to study the behavior of single and group driven pile of square pattern (4 piles) in case of floating pile (friction pile) with different spacing (2D, 4D, 6D) and length to diameter (L/D) ratio of (20) in this special medium dense soil (gypsum content 30% and 61%) under axial load condition. The investigation was carried out to measure the soil collapse before and after inundation. The results showed that the group efficiency for spacing 2D is less than one while for spacing 4D and 6D are more than that value. In addition, the spacing 4D was more efficient to carry 4 group pile in both dry and soaked cases, in addition, the result showed a high reduction in the bearing capacity at inundation state of group pile of (82% in gypsum content 30%) and ( 87% in gypsum content 61%) with respect to dry state.
Keywords: Gypseous Soil; Pile Spacing; Group Efficiency; Axial Load; Driven Pile.
Journal of Engineering and Development, Vol. 16, No.2, June 2012 ISSN 1813- 7822, 2012
The engineering problems faces civil engineer in building and construction, is almost foundation ... more The engineering problems faces civil engineer in building and construction, is almost foundation problems results from the properties of the beneath soil. One of the effected problems is the presence of gypseous soil. The presence of gypsum in some regions reaches up to 70%. Gypsum salts is one of highly dissolved salts in water. The solubility depends on temperature degree, atmospheric pressure, PH of the dissolved liquid. There are many treatments for such soils, some of them are physical like earth reinforcement, compaction. The others are chemical like the addition of lime, asphalt emulsion, oil products…etc(1).
The aim of this study is to investigate the ability of improving gypseous soil by reducing the collapsibility during wetting with water, by the addition of Portland cement with different percentages:( 1.5%, 4%, 6%,7.5%, 10%), to gypseous soil with at different densities14 kN/m3 and 11 kN/m3.
A laboratory model test consists of a cylindrical plastic container of 250 mm diameter and 400mm height. The soil was artificially prepared by mixing natural soil brought from a location near the Civil Engineering Department building in Diyala University, and mixed with 70% gypsum. The density of the soil was controlled by placing the required weight inside the container of known volume, to the required height. A rectangular footing 25mm*40mm made from steel was used. The stress was applied from a fix loading system designed especially for model tests and applying 46kPa stress. The aim of this setting is to control stress and to ensure keeping the dial gauges dry during tests.
The results of laboratory test on model samples shows a considerable reduction in collapsibility for gypsiferous soil models treated with cement and compaction, during soaking with water. The reduction percent in collapsibility was (95%) for treated model by (10%) of cement addition and with increasing soil density up to (14 kN/m3).
Keywords: gypseous soil, improvement, wetting.
Diyala Journal of Engineering Sciences, 2011
Gypseous soil is one of problematic soils facing civil engineer. The
problem appears when constru... more Gypseous soil is one of problematic soils facing civil engineer. The
problem appears when constructing heavy buildings or hydraulic structures on these soils
after wetted by water from rainfall or from the raising of water table level from any source.
On the other hand gypseous soil is considerably strong and has good properties when it
is dry. The dissolution of gypsum depends on many factors: gypsum content, temperature,
atmospheric pressure and others. Number of Remedies for these soils was carried out by
many investigators, some of these methods are not workable, and the others are expansive.
A new method of improving the collapsibility of such soil was presented by
Prewetting Gypseous soil with water many cycles using laboratory and field models with
different footing stress, which reduces the collapsibility of this soil primary. A laboratory
model of 320 mm diameter and 472 mm height made from thick plastic was used. Two soils
with different gypsum content 50% and 70%, brought from Aldor and Balad, in Salah Al
Deen government in Iraq, was used. A footing of circular base (50 mm diameter), applies 45
kN/m2 and 100kN/m2 stresses with the aid of fix weights placed on it. The results of
laboratory tests on the model samples shows a considerable reduction percent in the
deformation ratio (Settlement/width of footing (S/B)) of 63% achieved from the 3rd wetting
cycle by water for sample contain 50% gypsum. The reduction percent was 91% at the 3rd
cycle of prewetting for sample containing 70% gypsum tested at stress level up to 45kN/m2,
while it is 86% for the laboratory model with 100kN/m2 applied stress, with the same gypsum
content. The results of field test for the soil containing70% gypsum tested at 100kN/m2 stress
shows a pronounce improvement in the S/B value which gives a reduction percent reaches 90
%, which shows a considerable improvement in the collapsibility of this problematic soil.
Keywords:- Gypseous Soil, Soil Improvement.
Journal of Engineering and Development Vol. 19, No. 06, November 20 15, 2015
The presence of salts in soil may cause severe problems to structures constructed on it, because ... more The presence of salts in soil may cause severe problems to structures constructed on it, because of high dissolution of salt particles when subjected to water from any source. The primary objective for this study is to investigate the behavior of single footing over different percentages of sabkha soil (5%, 10%, 20%, and 40%). A laboratory model, manufactured locally was used for this study. The sabkha soil is prepared by mixing ordinary soil with specified quantities of sodium chloride salt to have different percentages of salinity. The footing used is 75mm diameter circular steel plate and 20mm thickness and hold fix stress, with the aid of loading frame which in turn is attached to a firm table. Dial gages is attached to the fix table and place on the footing, to record settlement with time. The study includes also the effect cement and lime addition with different percentages(1%, 3% and 5%), on the collapsibility of sabkha soil. Mixing sabkha soil with 5% of cement will reduce collapse potential (S/B%)* upon wetting, 97%. While mixing sabkha soil with 3% lime will reduce collapse settlement 47%, On the other hand, mixing sabkha soil with 1% cement slurry increase the collapsibility 3%. This study also, shines the light on the effect of compaction on the properties of sabkha soil. The collapse potential (S/B%)* reduced 50%, when increasing compaction of sabkha soil model from 17.7 to 19 kN/m3.
Keywords: Sabkha Soil, Collapsible, Chemical Additives, Treatment, Improvement.
Journal of Engineering and Development, Vol.19, No.2, march. 2015, ISSN 1813- 7822, 2015
The study includes also the effect of mixing the saline soil with some available additives: (1.5%... more The study includes also the effect of mixing the saline soil with some available additives: (1.5% and 3%) Lime material, (2% and 5%) of Cement material, with and without reinforcement. and investigates its effects on the collapsibility of such problematic collapsible soil. The best improvement was achieved by mixing the saline soil with (5% cement, and randomly distributed reinforcement using Ln/B=14.2%). this will reduce the collapsibility of such problematic soil, 90%.
First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010, 2010
Gypseous soils contains either Sodium or Calcium salts, which may be
considered the most problema... more Gypseous soils contains either Sodium or Calcium salts, which may be
considered the most problematic material for foundation engineer. It is associated with
settlement problem especially for heavy and hydraulic structures with the presence of water.
The risk begins from the first period of wetting or soaking these soils from any source:
(rainfall, rising of water table or from any reason). The water will fluctuate or infiltrate
through the soil particles and dissolve gypsum particles that fill the voids in the soil. The soil
particles will roll and slide and arrange at new positions, because of the disintegration of the
soil skeleton and the loosening of soil with the continuous dissolution of gypsum, which
translate the soil from solid to semi solid media, with time.
The dissolution of gypsum depends on many factors (gypsum content, temperature,
atmospheric pressure, and other factors). Another important factor which is the acidity of the
dissolves liquid must be considered. This study shades the lights on the effect of Acetic acid
(CH3COOH) on the collapsibility of gypseous soil.
A laboratory model includes 350mm diameter and 400mm height thick plastic
container and 18.4kN/m3 density gypsiferous soil prepared locally and compacted in three
layers, with70%gypsum content. The stress fixed at 47kPa was applied over 50mm diameter
circular footing. The relation between the soaking time and the deformation ratio
(settlement/width of footing S/B%) was investigated, with 5 cycles of soaking by the Acetic
acid.
The results of laboratory model tests show a pronounce effect of the acidity on the
collapsibility of gypsiferous soil. The results of deformation ratio S/B% was (1.22, 8, 12,
15.7, 50%) at the end of (1,2,3,4,5) prewetted cycles by CH3COOH acid, respectively. So the
Diyala Journal
of Engineering
Sciences
First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010
EFFECT OF ACETIC ACID ON THE COMPRESSIBILITY OF GYPSIFEROUS SOIL
Diyala Journal of Engineering Sciences – Special Issue
287
effect of Acetic Acid percent was considerably accelerating the collapsibility of gypsiferous
soil with cycling technique.
Keywords:- gypsiferous soil, compressibility.
Diyala Journal of Engineering Sciences, 2014
Calcareous or salty soils are the soils which are containing highly dissolved sodium or calcium s... more Calcareous or salty soils are the soils which are containing highly dissolved sodium or calcium salts in natural conditions. The dissolution of salts increases with temperature, atmospheric pressure, in addition to the acidity of the dissolves solution. Calcareous soil is stiff and very hard if it is in a dry phase; it becomes collapsible and very week when wetted with water. It is very dangerous for structures when constructing on such soil especially when high stresses are applied on it. Oil tanks or pipes may damage from any reason, and the oil products may leak from these structures to the soil and infiltrate through soil skeleton and may cause leaching to CaCO3 salt particles in some regions in Iraq, as example the Baiji Oil Station or Al-Mosel Dam, CaCO3 percent reaches more than 40%.
This study shines the lights about the behavior of Calcareous soil subjected to three oil derivatives (kerosene oil, crude oil, gas oil and a sample wetted with water to make good comparison ,and study effect of addition of this products on the collapsibility.
A laboratory model included soil with 70% and 50% CaCO3 compacted to 11 kN/m3. Fix stress system was used which applies 50 kN/m2, the loading frame was manufactured in a way that keeping the weights over footing stable without tilting. Three oil derivatives (Kerosene, Gasoil and crude oil) were used for laboratory model tests; by wetting Calcareous soil with it. One sample was wetted with water for comparison; the settlement was recorded with soaking time at a constant stress level.
The results of laboratory model tests shows that the settlements results from specimens soaked with lubricating oil, Gasoil and Kerosene, are much less than the settlements that belong to soaking with water (reduce settlement to about one third) and considered high improvement of such problematic soil by wetting with oil derivatives.
Diyala Journal of Engineering Sciences, 2014
Retaining walls may be required in a location where gypsum may present in soil in large percentag... more Retaining walls may be required in a location where gypsum may present in soil in large percentages .The behavior of retaining walls on ordinary soils is well known but the behavior of retaining walls resting on gypseons soils may be not well understood as the case of ordinary soils.
In this study it is intended to reflect the behavior of gravity retaining wall resting on collapsible soil. And to do so a small prototype model (600mm*500mm*200mm) is used with soil mixed in presumed percentages with different gypsum percentages (5%, 20%, 30%, 50%). In addition to a model with 30% gypsum and treated with 2.7% Cement dust mixed with soil founded retaining wall structure. After preparing the foundation gypseous soil, a small glass made retaining wall filled with sand, which represent gravity wall, is put over such bed and backfilled with ordinary sandy soil. Dial gauges are placed to side and top of wall to measure the rotation settlement behavior and collapse of system. 4kPa stress are applied to backfill soil as to accelerate collapse with leaching process commenced. Data are recorded and analyzed completely, which shows the behavior of such structures embedded with different gypsum content.
The improvement in rotation settlement and collapse for the retaining wall model reaches more than 89%, was gained after treating the embedded gypseous soil layer, with 2.7% cement dust.
Diyala Journal of Engineering Sciences, 2010
Gypseous soil is one of soils which presents a risk for engineering
structures, specially with hi... more Gypseous soil is one of soils which presents a risk for engineering
structures, specially with high contamination of gypsum, because of the problem of collapse
of soil under the footings, during soaking of these soils with water from any source. There is
another problem causes by leaching process and the continuous dissolution of the residual
undissolved gypsum inside the soil skeleton (A. Awn 2004), which creates cavities below
hydraulic structures and irrigation channels and reduce the bearing capacity of soil below
these heavy structures. It arises during the last two decades, the need for more practical and
easier method to measure the collapsibility in the laboratory and field, since more than 10%
of the total Iraqi area was gypseous soil and contain 15% to 70% gypsum.
During the last two decades the need was appear for constructing a new practical
device to measure the collapsibility during the soaking or leaching test, which is easier than
the conventional single or double odometer test (Jennings, J.E. and Knight, K. 1957), (Knight
K. 1963). This modified device which is designed and constructed locally, was effective to
measuring the collapsibility at field and laboratory in addition to the ability to measure the
compressibility at long time leaching for these types of problematic soil.
A model test includes a cylindrical plastic container with 45cm diameter and 500cm
height open from top to fix a water control system for fixing the head of water. An artificial
gypseferous soil was prepared with (70%, 60%, 50%, 40% and 30% gypsum) was placed
inside the container with 17.3kN/m3 density. A standards circular shaft applied 100kPa
stress was applied at all stages of tests.
The results of model tests and the new device used in this study shows a simple, high
activity in measuring the collapsibility, in addition to the ability to measure the
compressibility of such soil at leaching process, at the same time.
Gypseous soil is one of soils which presents a risk for engineering structures, specially with hi... more Gypseous soil is one of soils which presents a risk for engineering structures, specially with high contamination of gypsum, because of the problem of collapse of soil under the footings, during soaking of these soils with water from any source. There is another problem causes by leaching process and the continuous dissolution of the residual undissolved gypsum inside the soil skeleton (A. Awn 2004), which creates cavities below hydraulic structures and irrigation channels and reduce the bearing capacity of soil below these heavy structures. It arises during the last two decades, the need for more practical and easier method to measure the collapsibility in the laboratory and field, since more than 10% of the total Iraqi area was gypseous soil and contain 15% to 70% gypsum.
International Journal of Engineering Trends and Technology (IJETT) – Volume 51 Number 3 September 2017, 2017
This study is presented to investigate the
behavior of concrete pile in gypseous soil with 30%,
a... more This study is presented to investigate the
behavior of concrete pile in gypseous soil with 30%,
and 66% gypsum content subjected to tension load,
also including a comparison to illustrate the
behavior of solid steel and concrete piles types
(slenderness ratio (L/D) = 10) embedded in the
same soil (66% gypsum content) for both dry and 24
hr soaked specimens. The results showed 82%, and
45% capacity decrease to soaked specimens for
both 30%, and 66% gypsum content samples
respectively. It is argued that this lack in capacity is
due to the dissolution of the gypsum. The latter
reason interprets the 66% lack in the pullout
capacity for the steel pile embedded in 66% gypsum
content. Increasing gypsum content enhanced
capacity of concrete piles for both dry and soaked
samples. The pullout capacity of steel pile illustrates
general trend to be more than the corresponding
values of concrete types to about 46% for dry and
5% for soaked samples. That behavior can be
attributed to the friction or adhesion between pile
and soil particles for steel is more than concrete
types.
Keywords- pullout, piles, gypseous soil, laboratory
model, soaking, pile capacity
Geotechnical Engineering Journal of the SEAGS & AGSSEA Vol. 48 No. 4 December 2017 ISSN 0046-5828, 2017
To model the behavior of expansive soil, it seems necessary to move towards Elastoplast models t... more To model the behavior of expansive soil, it seems necessary to move towards Elastoplast models that have been used for
different types of clay. Hardening soil model is chosen in this study. Retaining walls rested on expansive soils are subjected to uplift and
lateral forces due to soil swelling. More importantly, the swelling in expansive soil tends to cause additional lateral pressure on wall that
caused deformations and bending. Various pattern types of helical piles are used to reduce the vertical and lateral movement of retaining
wall constructed on expansive soil. The back fill soil beyond retaining wall is affected by swelling of expansive soil that caused additional
lateral earth pressure on the wall of retaining wall. This study showed that the use of inclined helical piles beside vertical helical piles under
the base of retaining wall decreased vertical movement 94% and lateral movement 70% for ratio of length of helical pile to depth of
expansive soil (L/H) equal to 3.2. In general, the presence of helical piles below retaining wall resisted and controlled the vertical movement
but do not control lateral movement except the case of using inclined helical piles.
The presence of salts in soil may cause severe problems to structures constructed on it, because ... more The presence of salts in soil may cause severe problems to structures constructed on it, because of high dissolution of salt particles when subjected to water from any source. The primary objective for this study is to investigate the behavior of single footing over different percentages of sabkha soil (5%, 10%, 20%, and 40%). A laboratory model, manufactured locally was used for this study. The sabkha soil is prepared by mixing ordinary soil with specified quantities of sodium chloride salt to have different percentages of salinity. The footing used is 75mm diameter circular steel plate and 20mm thickness and hold fix stress, with the aid of loading frame which in turn is attached to a firm table. Dial gages is attached to the fix table and place on the footing, to record settlement with time. The study includes also the effect cement and lime addition with different percentages(1%, 3% and 5%), on the collapsibility of sabkha soil. Mixing sabkha soil with 5% of cement will reduce collapse potential (S/B%)* upon wetting, 97%. While mixing sabkha soil with 3% lime will reduce collapse settlement 47%, On the other hand, mixing sabkha soil with 1% cement slurry increase the collapsibility 3%. This study also, shines the light on the effect of compaction on the properties of sabkha soil. The collapse potential (S/B%)* reduced 50%, when increasing compaction of sabkha soil model from 17.7 to 19 kN/m3.
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Papers by Safa Hussain Abid Awn
Due to the wide spread of the gypseous soil in the world in general form and especially in Iraq which reaches 70% in some regions. The problem of such soil appears at the first time of wetting it from any source and the soil become loose.
In the present study, we highlight on the investigation the behavior of steel pile in gypseous soil of 30%, and 60% gypsum content in both dry and soaking cases when subjected to pure tension load, and make a comparison between the pullout capacity of that pile when embedded in both type of gypseous soils. All tests of pile was conducted via used manufactured laboratory model which constructed specially for that purpose.
The gypseous soil used was brought from Salah Al-Deen governorate in Iraq, with 30%, and 60% gypsum content . The pile used is a solid steel with L/D equal to 10. The model was examined in a dry and soaking with water for 24 hour to show the effect of the presence of water on the pile capacity. Based on the result of the present study it can be recognize a substantial decrease in the pullout capacity of the pile of about 64%, and 68% after soaking of the soil-pile model for 24 hour with water for both gypseous soils of 30%, and 60% respectivily due to the dissolution of the gypsum content that related between the soil particles.
2
Which must be taken into consideration when constructing pile foundation on such collapsible soil. The results showed also that the pullout capacity of steel pile in gypseous soil of 60% gypsum content is more than that in gypseous soil of 30% gypsum content in both dry and soaking cases.
Keywords: Gypseous Soil; Pile Spacing; Group Efficiency; Axial Load; Driven Pile.
The aim of this study is to investigate the ability of improving gypseous soil by reducing the collapsibility during wetting with water, by the addition of Portland cement with different percentages:( 1.5%, 4%, 6%,7.5%, 10%), to gypseous soil with at different densities14 kN/m3 and 11 kN/m3.
A laboratory model test consists of a cylindrical plastic container of 250 mm diameter and 400mm height. The soil was artificially prepared by mixing natural soil brought from a location near the Civil Engineering Department building in Diyala University, and mixed with 70% gypsum. The density of the soil was controlled by placing the required weight inside the container of known volume, to the required height. A rectangular footing 25mm*40mm made from steel was used. The stress was applied from a fix loading system designed especially for model tests and applying 46kPa stress. The aim of this setting is to control stress and to ensure keeping the dial gauges dry during tests.
The results of laboratory test on model samples shows a considerable reduction in collapsibility for gypsiferous soil models treated with cement and compaction, during soaking with water. The reduction percent in collapsibility was (95%) for treated model by (10%) of cement addition and with increasing soil density up to (14 kN/m3).
Keywords: gypseous soil, improvement, wetting.
problem appears when constructing heavy buildings or hydraulic structures on these soils
after wetted by water from rainfall or from the raising of water table level from any source.
On the other hand gypseous soil is considerably strong and has good properties when it
is dry. The dissolution of gypsum depends on many factors: gypsum content, temperature,
atmospheric pressure and others. Number of Remedies for these soils was carried out by
many investigators, some of these methods are not workable, and the others are expansive.
A new method of improving the collapsibility of such soil was presented by
Prewetting Gypseous soil with water many cycles using laboratory and field models with
different footing stress, which reduces the collapsibility of this soil primary. A laboratory
model of 320 mm diameter and 472 mm height made from thick plastic was used. Two soils
with different gypsum content 50% and 70%, brought from Aldor and Balad, in Salah Al
Deen government in Iraq, was used. A footing of circular base (50 mm diameter), applies 45
kN/m2 and 100kN/m2 stresses with the aid of fix weights placed on it. The results of
laboratory tests on the model samples shows a considerable reduction percent in the
deformation ratio (Settlement/width of footing (S/B)) of 63% achieved from the 3rd wetting
cycle by water for sample contain 50% gypsum. The reduction percent was 91% at the 3rd
cycle of prewetting for sample containing 70% gypsum tested at stress level up to 45kN/m2,
while it is 86% for the laboratory model with 100kN/m2 applied stress, with the same gypsum
content. The results of field test for the soil containing70% gypsum tested at 100kN/m2 stress
shows a pronounce improvement in the S/B value which gives a reduction percent reaches 90
%, which shows a considerable improvement in the collapsibility of this problematic soil.
Keywords:- Gypseous Soil, Soil Improvement.
Keywords: Sabkha Soil, Collapsible, Chemical Additives, Treatment, Improvement.
considered the most problematic material for foundation engineer. It is associated with
settlement problem especially for heavy and hydraulic structures with the presence of water.
The risk begins from the first period of wetting or soaking these soils from any source:
(rainfall, rising of water table or from any reason). The water will fluctuate or infiltrate
through the soil particles and dissolve gypsum particles that fill the voids in the soil. The soil
particles will roll and slide and arrange at new positions, because of the disintegration of the
soil skeleton and the loosening of soil with the continuous dissolution of gypsum, which
translate the soil from solid to semi solid media, with time.
The dissolution of gypsum depends on many factors (gypsum content, temperature,
atmospheric pressure, and other factors). Another important factor which is the acidity of the
dissolves liquid must be considered. This study shades the lights on the effect of Acetic acid
(CH3COOH) on the collapsibility of gypseous soil.
A laboratory model includes 350mm diameter and 400mm height thick plastic
container and 18.4kN/m3 density gypsiferous soil prepared locally and compacted in three
layers, with70%gypsum content. The stress fixed at 47kPa was applied over 50mm diameter
circular footing. The relation between the soaking time and the deformation ratio
(settlement/width of footing S/B%) was investigated, with 5 cycles of soaking by the Acetic
acid.
The results of laboratory model tests show a pronounce effect of the acidity on the
collapsibility of gypsiferous soil. The results of deformation ratio S/B% was (1.22, 8, 12,
15.7, 50%) at the end of (1,2,3,4,5) prewetted cycles by CH3COOH acid, respectively. So the
Diyala Journal
of Engineering
Sciences
First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010
EFFECT OF ACETIC ACID ON THE COMPRESSIBILITY OF GYPSIFEROUS SOIL
Diyala Journal of Engineering Sciences – Special Issue
287
effect of Acetic Acid percent was considerably accelerating the collapsibility of gypsiferous
soil with cycling technique.
Keywords:- gypsiferous soil, compressibility.
This study shines the lights about the behavior of Calcareous soil subjected to three oil derivatives (kerosene oil, crude oil, gas oil and a sample wetted with water to make good comparison ,and study effect of addition of this products on the collapsibility.
A laboratory model included soil with 70% and 50% CaCO3 compacted to 11 kN/m3. Fix stress system was used which applies 50 kN/m2, the loading frame was manufactured in a way that keeping the weights over footing stable without tilting. Three oil derivatives (Kerosene, Gasoil and crude oil) were used for laboratory model tests; by wetting Calcareous soil with it. One sample was wetted with water for comparison; the settlement was recorded with soaking time at a constant stress level.
The results of laboratory model tests shows that the settlements results from specimens soaked with lubricating oil, Gasoil and Kerosene, are much less than the settlements that belong to soaking with water (reduce settlement to about one third) and considered high improvement of such problematic soil by wetting with oil derivatives.
In this study it is intended to reflect the behavior of gravity retaining wall resting on collapsible soil. And to do so a small prototype model (600mm*500mm*200mm) is used with soil mixed in presumed percentages with different gypsum percentages (5%, 20%, 30%, 50%). In addition to a model with 30% gypsum and treated with 2.7% Cement dust mixed with soil founded retaining wall structure. After preparing the foundation gypseous soil, a small glass made retaining wall filled with sand, which represent gravity wall, is put over such bed and backfilled with ordinary sandy soil. Dial gauges are placed to side and top of wall to measure the rotation settlement behavior and collapse of system. 4kPa stress are applied to backfill soil as to accelerate collapse with leaching process commenced. Data are recorded and analyzed completely, which shows the behavior of such structures embedded with different gypsum content.
The improvement in rotation settlement and collapse for the retaining wall model reaches more than 89%, was gained after treating the embedded gypseous soil layer, with 2.7% cement dust.
structures, specially with high contamination of gypsum, because of the problem of collapse
of soil under the footings, during soaking of these soils with water from any source. There is
another problem causes by leaching process and the continuous dissolution of the residual
undissolved gypsum inside the soil skeleton (A. Awn 2004), which creates cavities below
hydraulic structures and irrigation channels and reduce the bearing capacity of soil below
these heavy structures. It arises during the last two decades, the need for more practical and
easier method to measure the collapsibility in the laboratory and field, since more than 10%
of the total Iraqi area was gypseous soil and contain 15% to 70% gypsum.
During the last two decades the need was appear for constructing a new practical
device to measure the collapsibility during the soaking or leaching test, which is easier than
the conventional single or double odometer test (Jennings, J.E. and Knight, K. 1957), (Knight
K. 1963). This modified device which is designed and constructed locally, was effective to
measuring the collapsibility at field and laboratory in addition to the ability to measure the
compressibility at long time leaching for these types of problematic soil.
A model test includes a cylindrical plastic container with 45cm diameter and 500cm
height open from top to fix a water control system for fixing the head of water. An artificial
gypseferous soil was prepared with (70%, 60%, 50%, 40% and 30% gypsum) was placed
inside the container with 17.3kN/m3 density. A standards circular shaft applied 100kPa
stress was applied at all stages of tests.
The results of model tests and the new device used in this study shows a simple, high
activity in measuring the collapsibility, in addition to the ability to measure the
compressibility of such soil at leaching process, at the same time.
behavior of concrete pile in gypseous soil with 30%,
and 66% gypsum content subjected to tension load,
also including a comparison to illustrate the
behavior of solid steel and concrete piles types
(slenderness ratio (L/D) = 10) embedded in the
same soil (66% gypsum content) for both dry and 24
hr soaked specimens. The results showed 82%, and
45% capacity decrease to soaked specimens for
both 30%, and 66% gypsum content samples
respectively. It is argued that this lack in capacity is
due to the dissolution of the gypsum. The latter
reason interprets the 66% lack in the pullout
capacity for the steel pile embedded in 66% gypsum
content. Increasing gypsum content enhanced
capacity of concrete piles for both dry and soaked
samples. The pullout capacity of steel pile illustrates
general trend to be more than the corresponding
values of concrete types to about 46% for dry and
5% for soaked samples. That behavior can be
attributed to the friction or adhesion between pile
and soil particles for steel is more than concrete
types.
Keywords- pullout, piles, gypseous soil, laboratory
model, soaking, pile capacity
different types of clay. Hardening soil model is chosen in this study. Retaining walls rested on expansive soils are subjected to uplift and
lateral forces due to soil swelling. More importantly, the swelling in expansive soil tends to cause additional lateral pressure on wall that
caused deformations and bending. Various pattern types of helical piles are used to reduce the vertical and lateral movement of retaining
wall constructed on expansive soil. The back fill soil beyond retaining wall is affected by swelling of expansive soil that caused additional
lateral earth pressure on the wall of retaining wall. This study showed that the use of inclined helical piles beside vertical helical piles under
the base of retaining wall decreased vertical movement 94% and lateral movement 70% for ratio of length of helical pile to depth of
expansive soil (L/H) equal to 3.2. In general, the presence of helical piles below retaining wall resisted and controlled the vertical movement
but do not control lateral movement except the case of using inclined helical piles.
Due to the wide spread of the gypseous soil in the world in general form and especially in Iraq which reaches 70% in some regions. The problem of such soil appears at the first time of wetting it from any source and the soil become loose.
In the present study, we highlight on the investigation the behavior of steel pile in gypseous soil of 30%, and 60% gypsum content in both dry and soaking cases when subjected to pure tension load, and make a comparison between the pullout capacity of that pile when embedded in both type of gypseous soils. All tests of pile was conducted via used manufactured laboratory model which constructed specially for that purpose.
The gypseous soil used was brought from Salah Al-Deen governorate in Iraq, with 30%, and 60% gypsum content . The pile used is a solid steel with L/D equal to 10. The model was examined in a dry and soaking with water for 24 hour to show the effect of the presence of water on the pile capacity. Based on the result of the present study it can be recognize a substantial decrease in the pullout capacity of the pile of about 64%, and 68% after soaking of the soil-pile model for 24 hour with water for both gypseous soils of 30%, and 60% respectivily due to the dissolution of the gypsum content that related between the soil particles.
2
Which must be taken into consideration when constructing pile foundation on such collapsible soil. The results showed also that the pullout capacity of steel pile in gypseous soil of 60% gypsum content is more than that in gypseous soil of 30% gypsum content in both dry and soaking cases.
Keywords: Gypseous Soil; Pile Spacing; Group Efficiency; Axial Load; Driven Pile.
The aim of this study is to investigate the ability of improving gypseous soil by reducing the collapsibility during wetting with water, by the addition of Portland cement with different percentages:( 1.5%, 4%, 6%,7.5%, 10%), to gypseous soil with at different densities14 kN/m3 and 11 kN/m3.
A laboratory model test consists of a cylindrical plastic container of 250 mm diameter and 400mm height. The soil was artificially prepared by mixing natural soil brought from a location near the Civil Engineering Department building in Diyala University, and mixed with 70% gypsum. The density of the soil was controlled by placing the required weight inside the container of known volume, to the required height. A rectangular footing 25mm*40mm made from steel was used. The stress was applied from a fix loading system designed especially for model tests and applying 46kPa stress. The aim of this setting is to control stress and to ensure keeping the dial gauges dry during tests.
The results of laboratory test on model samples shows a considerable reduction in collapsibility for gypsiferous soil models treated with cement and compaction, during soaking with water. The reduction percent in collapsibility was (95%) for treated model by (10%) of cement addition and with increasing soil density up to (14 kN/m3).
Keywords: gypseous soil, improvement, wetting.
problem appears when constructing heavy buildings or hydraulic structures on these soils
after wetted by water from rainfall or from the raising of water table level from any source.
On the other hand gypseous soil is considerably strong and has good properties when it
is dry. The dissolution of gypsum depends on many factors: gypsum content, temperature,
atmospheric pressure and others. Number of Remedies for these soils was carried out by
many investigators, some of these methods are not workable, and the others are expansive.
A new method of improving the collapsibility of such soil was presented by
Prewetting Gypseous soil with water many cycles using laboratory and field models with
different footing stress, which reduces the collapsibility of this soil primary. A laboratory
model of 320 mm diameter and 472 mm height made from thick plastic was used. Two soils
with different gypsum content 50% and 70%, brought from Aldor and Balad, in Salah Al
Deen government in Iraq, was used. A footing of circular base (50 mm diameter), applies 45
kN/m2 and 100kN/m2 stresses with the aid of fix weights placed on it. The results of
laboratory tests on the model samples shows a considerable reduction percent in the
deformation ratio (Settlement/width of footing (S/B)) of 63% achieved from the 3rd wetting
cycle by water for sample contain 50% gypsum. The reduction percent was 91% at the 3rd
cycle of prewetting for sample containing 70% gypsum tested at stress level up to 45kN/m2,
while it is 86% for the laboratory model with 100kN/m2 applied stress, with the same gypsum
content. The results of field test for the soil containing70% gypsum tested at 100kN/m2 stress
shows a pronounce improvement in the S/B value which gives a reduction percent reaches 90
%, which shows a considerable improvement in the collapsibility of this problematic soil.
Keywords:- Gypseous Soil, Soil Improvement.
Keywords: Sabkha Soil, Collapsible, Chemical Additives, Treatment, Improvement.
considered the most problematic material for foundation engineer. It is associated with
settlement problem especially for heavy and hydraulic structures with the presence of water.
The risk begins from the first period of wetting or soaking these soils from any source:
(rainfall, rising of water table or from any reason). The water will fluctuate or infiltrate
through the soil particles and dissolve gypsum particles that fill the voids in the soil. The soil
particles will roll and slide and arrange at new positions, because of the disintegration of the
soil skeleton and the loosening of soil with the continuous dissolution of gypsum, which
translate the soil from solid to semi solid media, with time.
The dissolution of gypsum depends on many factors (gypsum content, temperature,
atmospheric pressure, and other factors). Another important factor which is the acidity of the
dissolves liquid must be considered. This study shades the lights on the effect of Acetic acid
(CH3COOH) on the collapsibility of gypseous soil.
A laboratory model includes 350mm diameter and 400mm height thick plastic
container and 18.4kN/m3 density gypsiferous soil prepared locally and compacted in three
layers, with70%gypsum content. The stress fixed at 47kPa was applied over 50mm diameter
circular footing. The relation between the soaking time and the deformation ratio
(settlement/width of footing S/B%) was investigated, with 5 cycles of soaking by the Acetic
acid.
The results of laboratory model tests show a pronounce effect of the acidity on the
collapsibility of gypsiferous soil. The results of deformation ratio S/B% was (1.22, 8, 12,
15.7, 50%) at the end of (1,2,3,4,5) prewetted cycles by CH3COOH acid, respectively. So the
Diyala Journal
of Engineering
Sciences
First Engineering Scientific Conference-College of Engineering –University of Diyala, 22-23 Dec. 2010
EFFECT OF ACETIC ACID ON THE COMPRESSIBILITY OF GYPSIFEROUS SOIL
Diyala Journal of Engineering Sciences – Special Issue
287
effect of Acetic Acid percent was considerably accelerating the collapsibility of gypsiferous
soil with cycling technique.
Keywords:- gypsiferous soil, compressibility.
This study shines the lights about the behavior of Calcareous soil subjected to three oil derivatives (kerosene oil, crude oil, gas oil and a sample wetted with water to make good comparison ,and study effect of addition of this products on the collapsibility.
A laboratory model included soil with 70% and 50% CaCO3 compacted to 11 kN/m3. Fix stress system was used which applies 50 kN/m2, the loading frame was manufactured in a way that keeping the weights over footing stable without tilting. Three oil derivatives (Kerosene, Gasoil and crude oil) were used for laboratory model tests; by wetting Calcareous soil with it. One sample was wetted with water for comparison; the settlement was recorded with soaking time at a constant stress level.
The results of laboratory model tests shows that the settlements results from specimens soaked with lubricating oil, Gasoil and Kerosene, are much less than the settlements that belong to soaking with water (reduce settlement to about one third) and considered high improvement of such problematic soil by wetting with oil derivatives.
In this study it is intended to reflect the behavior of gravity retaining wall resting on collapsible soil. And to do so a small prototype model (600mm*500mm*200mm) is used with soil mixed in presumed percentages with different gypsum percentages (5%, 20%, 30%, 50%). In addition to a model with 30% gypsum and treated with 2.7% Cement dust mixed with soil founded retaining wall structure. After preparing the foundation gypseous soil, a small glass made retaining wall filled with sand, which represent gravity wall, is put over such bed and backfilled with ordinary sandy soil. Dial gauges are placed to side and top of wall to measure the rotation settlement behavior and collapse of system. 4kPa stress are applied to backfill soil as to accelerate collapse with leaching process commenced. Data are recorded and analyzed completely, which shows the behavior of such structures embedded with different gypsum content.
The improvement in rotation settlement and collapse for the retaining wall model reaches more than 89%, was gained after treating the embedded gypseous soil layer, with 2.7% cement dust.
structures, specially with high contamination of gypsum, because of the problem of collapse
of soil under the footings, during soaking of these soils with water from any source. There is
another problem causes by leaching process and the continuous dissolution of the residual
undissolved gypsum inside the soil skeleton (A. Awn 2004), which creates cavities below
hydraulic structures and irrigation channels and reduce the bearing capacity of soil below
these heavy structures. It arises during the last two decades, the need for more practical and
easier method to measure the collapsibility in the laboratory and field, since more than 10%
of the total Iraqi area was gypseous soil and contain 15% to 70% gypsum.
During the last two decades the need was appear for constructing a new practical
device to measure the collapsibility during the soaking or leaching test, which is easier than
the conventional single or double odometer test (Jennings, J.E. and Knight, K. 1957), (Knight
K. 1963). This modified device which is designed and constructed locally, was effective to
measuring the collapsibility at field and laboratory in addition to the ability to measure the
compressibility at long time leaching for these types of problematic soil.
A model test includes a cylindrical plastic container with 45cm diameter and 500cm
height open from top to fix a water control system for fixing the head of water. An artificial
gypseferous soil was prepared with (70%, 60%, 50%, 40% and 30% gypsum) was placed
inside the container with 17.3kN/m3 density. A standards circular shaft applied 100kPa
stress was applied at all stages of tests.
The results of model tests and the new device used in this study shows a simple, high
activity in measuring the collapsibility, in addition to the ability to measure the
compressibility of such soil at leaching process, at the same time.
behavior of concrete pile in gypseous soil with 30%,
and 66% gypsum content subjected to tension load,
also including a comparison to illustrate the
behavior of solid steel and concrete piles types
(slenderness ratio (L/D) = 10) embedded in the
same soil (66% gypsum content) for both dry and 24
hr soaked specimens. The results showed 82%, and
45% capacity decrease to soaked specimens for
both 30%, and 66% gypsum content samples
respectively. It is argued that this lack in capacity is
due to the dissolution of the gypsum. The latter
reason interprets the 66% lack in the pullout
capacity for the steel pile embedded in 66% gypsum
content. Increasing gypsum content enhanced
capacity of concrete piles for both dry and soaked
samples. The pullout capacity of steel pile illustrates
general trend to be more than the corresponding
values of concrete types to about 46% for dry and
5% for soaked samples. That behavior can be
attributed to the friction or adhesion between pile
and soil particles for steel is more than concrete
types.
Keywords- pullout, piles, gypseous soil, laboratory
model, soaking, pile capacity
different types of clay. Hardening soil model is chosen in this study. Retaining walls rested on expansive soils are subjected to uplift and
lateral forces due to soil swelling. More importantly, the swelling in expansive soil tends to cause additional lateral pressure on wall that
caused deformations and bending. Various pattern types of helical piles are used to reduce the vertical and lateral movement of retaining
wall constructed on expansive soil. The back fill soil beyond retaining wall is affected by swelling of expansive soil that caused additional
lateral earth pressure on the wall of retaining wall. This study showed that the use of inclined helical piles beside vertical helical piles under
the base of retaining wall decreased vertical movement 94% and lateral movement 70% for ratio of length of helical pile to depth of
expansive soil (L/H) equal to 3.2. In general, the presence of helical piles below retaining wall resisted and controlled the vertical movement
but do not control lateral movement except the case of using inclined helical piles.