Print ISSN: 1681-6900

Online ISSN: 2412-0758

Issue 20,

Issue 20


Prediction of Square Footing Settlement under Eccentric Loading on Gypseous Soil through Proposed Surface for Dry and Soaked States

Bushra S. Z. Albusoda; Abdul-Kareem E; R. S.Hussein

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 217-237

Gypseous soils as any other soils deform under loading, this deformation differs greatly between its dry state and its soaked state. This deformation also differs when the loading is applied with eccentricity.
An experimental work was conducted on a square footing model (100 mm  100 mm) above gypseous soil 450 mm thick. Loading was applied at the center of the footing (e/B = 0) and at an eccentricity of (e/B = 0.05, 0.1, 0.15, 0.2) for its dry state and its soaked state. Settlement was obtained at the center and at the base soil of the footing for each state.
The data obtained was normalized and a proposed surface was obtained for each of the two states (dry and soaked) and at two places (center and edge). Four proposed equations were obtained represented four cases of research i) Dry center, ii) Dry edge, iii) Soaked center, and iv) Soaked edge. The four equations showed very good agreement with the data obtained from the experiment.
Artificial Neural Network model was also used to obtain a neural network representing the proposed surface for the abovementioned four cases and also a very good agreement was obtained.
It is concluded that a proposed surface for the central and eccentric loading on square footing for gypseous soil showed a good agreement with the experimental data and therefore may be used for settlement prediction.

Integration between Surface Geoelectrical and Geotechnical Datasets in Salah Al-DinArea, Central Iraq

Hussein H. Karim; T. Schanz; Ali N. Ibrahim

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 238-262

This research aims to assess some geotechnical properties and aquifer parameters and consequently the applicability of predicting its properties from surface electrical resistivity. The main output is to get several geotechnical properties particularly those concerned with groundwater studies (such as porosity, and permeability) and aquifer properties (such as resistivity, hydraulic conductivity and transmissivity). To achieve this goal, interpretations of 50 Schlumberger VES points distributed along 5 profiles, located in Salah Al-Din Governorate in central Iraq, have been carried out. Sounding curve types obtained in the area are mostly QQ and HK types. The application of VES technique has provided detailed information on the thickness and hydrogeoelectrical characteristics of the aquifers in the study area. Based on VES interpretation and their correlation with available geotechnical data, four geoelectric layers were identified; these are topsoil, unsaturated zone, saturated zone and the conductive layer. In addition, two aquifers have been identified in the area under study. The upper is unconfined appeared mainly in eastern side of Tigris River, whereas the lower is semiconfined-confined appeared mainly in the western side of the River. Different target zones for groundwater potential have been recognized on the basis of geoelectric parameters that range between poor-good groundwater potential. Generally, the quality of ground water is considered to be brackish with respect to their total dissolved solids (TDS). Several discontinuities (probably faults) have been delineated according to the form of resistivity curves and geoelectrical sections. The study states that the resistivity values increase with increasing gypsum content in dry condition. But for saturated soil with high water content, the conductivity increases and hence the resistivity decreases. Besides, the increase in gypsum content leads to increase the porosity, then the resistivity increases too. A remarkable correlation is found among topsoil gypsum content, surface resistivity and porosity with Landsat image.

Geotechnical Properties of Compacted Silty Clay Mixed With Different Sludge Contents

Bushra S. Zbar; Mohammed A. Khan; Ahmed S. Jawad

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 263-279

The presence of organic matter in soil may cause different problems depending on many factors such as type and contents of these organic materials. A testing program was carried out to study the geotechnical properties and the behavior of organic matter obtained by the addition of a sludge material brought from a sewerage treatment plant.The tests include classification, chemical, compaction, compressibility and shear strength tests. Based on the results, several conclusions have been obtained. Both liquid and plastic limits increased with increasing organic matter. Regarding compaction test, it can be noticed that both maximum dry density and optimum moisture content slightly decreased with increasing organic contents then tends to increase.Through the observation of shear strength test results, qu and cu increased with increasing organic matter contents and then tends to decrease in similar manner to the density water relation of compaction test. Regarding compressibility, organic content, water content, void ratio and arrangement of soil particles are dominant factors controlling this property. The compression behavior of organic soils varies from the compression behavior of other types of soils in two ways, first the compression of organic soils is much larger and second, the creep or secondary compression plays an important role in determining the total settlement as shown in developing a unique relationship for organic soils.

Total and Matric Suction in Unsaturated Soil with the Existence of Different Salts Content

Mohammed Y. Fattah; Asmaa Y. Yahya; Maysam Th. Al-Hadidi; Balqees A. Ahmed

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 280-298

Soils located above the groundwater table are generally unsaturated and exhibit negative pore-water pressures. A soil-water characteristic curve (SWCC) that relates the water content of a soil to matric suction is an important relationship for the unsaturated soil mechanics. The SWCC essentially shows the ability of an unsaturated soil to retain water under various matric suctions. The filter paper method is a soil suction measurement technique. Soil suction is one of the most important parameters describing the moisture condition of unsaturated soils. The measurement of soil suction is crucial for applying the theories of the engineering behavior of unsaturated soils.
In this paper, three soil samples were collected from three sites within Baghdad city in Iraq. These soils have different properties and they were prepared at different degrees of saturation. For each sample, the total and matric suction were measured by the filter paper method at different degrees of saturation. The soil samples were mixed with different percentages of Nacl salt. It was concluded that the suction increases with decrease of the degree of saturation. The relationships between the total and matric suction and the filter paper water content are approximately linear and indicate decrease of suction with increase of the filter paper water content. All soil samples exhibit unique linear relationship between the total suction and filter paper water content and matric suction. When salt exists in the soil, there is a noticeable increase in both matric and total suction.

Effect of Geotextile Reinforcement on Flexible Pavement Roads

adi; Abdul Hadi Meteab AL Sa; Najah Mahdi Lateef Al -Maimuri; Dler Abdullah Omar al-mamany

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 299-315

A field full scale flexible road is constructed and the effects of geotextile reinforcement in paved road are tested by measuring the occurred rutting. The effect of different numbers and positions of geotextile reinforcement using seven road sections are evaluated and compared with unreinforced pavement section. It is found that a maximum reduction of rut depth is 96% when using three reinforcement layers at three different road layers interfaces, and a minimum reduction is 52% when using one reinforcement layer at interface I ( between wearing and binder layers) under the effect of maximum load cycles of 10000. The minimum Traffic Benefit Ratio (TBR= ratio between load cycles on a reinforced section to that of unreinforced section for the same rut depth) is found to be 4 when using one reinforcement layer in the interfaces I , and extremely large values for other reinforcement cases. Once, the above values appear how the service life of the paved road is increased by using geotextile reinforcement.
The cost-benefit analysis is also adopted in this research and found that by using one reinforcement layer the road cost is increased by only 14% resulting in increment value of TBR to 4 (this means that the road life is doubled 4 times if all other circumstances are fixed). This is a minimum case benefit when comparing it with all other cases; it is found that TBR values are exaggerated when different numbers and positions of geotextile reinforcement layers are used.

Influence of Poypropylene Fibers on the Soil Stabilization

Heba Dawood Salim

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 316-323

In this paper the polypropylene fiber was chosen as the additive material to know how it is effect on the soil stabilization, which it is used as additive for concret mixture; the polypropylene fiber is inert material and does not interact with water. The paper studies the addition of this material to a silty clay soil and its effect on the consistency limits, shear strength and compaction of the blended materials. The results show that there is an improvement in the shear strength only when the addition of the rate 1% and 2%from soil weight; either the effective of the consistency limit it was increasing the water content with increasing the rate of the addition material, because it have drink of water. At the compaction test it was founded that the increasing in dry density at the addition of 1% and 2% and reducing its value at the addition of 3% with increasing of water optimization.

Stability Behavior of Lime Stabilized Gypseous Soil

Abdulrahman Aldaood; Marwen Bouasker; Amina A Khalil; Ibrahim Al-Kiki

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 324-338

In arid and semi-arid zones, gypsum (CaSO4.2H2O) is one of the soluble of the common minerals that found in soils. In Iraq, gypseous soils is a worldwide stability problem that causes extensive damage upon wetting, and occur in certain areas characterized by variation of climatic conditions. The results of the stability behavior of lime stabilized gypseous soil where present in this paper under different tests. These tests were erosion, leaching and soaking. Erosion test was conducted under different variables such as water temperature, water velocity and flow duration. The soil used in this study was taken from a site near Al – Hader district about (80 km) from Mosul city. Its main geotechnical index properties are liquid limit is (46%), plastic limit (22%) and specific gravity is 2.58. The amount of the gypsum was 20%. The soil samples were treated with optimum lime percent (4%) depending on the Illinois procedure. A gypseous soil with 20% gypsum content was used and stabilized with 4% lime. All stabilized soil samples were cured for 2 days at 490 C. The results indicate that, the loss in weight increased for samples subjected to the flowing water, further increase in weight losses with increasing flow duration. High water velocity causes increasing in weight losses and loss in gypsum content , more loss in weight and more loss in gypsum content, for all values of flow duration and water temperature. Unconfined compressive strength decreased during the soaking process and further decrease in strength with increasing soaking duration. The leaching effect causes a continuous increasing in the permeability value of unstabilized soil samples, while it has an insignificant effect on the permeability of lime stabilized soil samples. Leaching

is a time-dependent process. The results showed that the pH values of natural and lime stabilized soil samples decreases during leaching process.

Effect of Suction on Volumetric Yielding Behavior under Different Initial Conditions for Fine-Grained Soils

Yasir Al-Badran; Tom Schanz

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 339-358

The unsaturated soils are difficult to consider within the framework of classical (saturated) soil mechanics. In general, the unsaturated soil is stiffer than the saturated one (hardening), so the location and slope of normal consolidated line (NCL) or the volumetric yielding behavior of unsaturated soil is different from the saturated behavior. This work investigates the volumetric yielding behavior of unsaturated soil; by determine the One-dimensional normal consolidated lines (NCL’s) under different suctions. Two materials namely pure Calcigel bentonite (100B) and a mixture of 30% Calcigel bentonite and 70 % Haider sand (30B) were prepared at two initial conditions (i.e. slurry and loose states). In this type of test, after reaching to the designed suction, the net stress is increased through the test while the suction is kept constant. Thirteen 30B specimens and two 100B specimens were tested under constant suction condition. The constant applied suction in this study was varied from 0 kPa till 39000 kPa because of the possibility to increase the preconsolidation pressure (yield stress) more than 24000 kPa (the maximum limit of the used one-dimensional high stress consolidation equipments). Two techniques (i.e. axis translation technique and vapor equilibrium technique) were used to apply and control suction on tests. The controlled-suction one-dimensional high stress consolidation tests results show that the position and the slope of NCL’s depend on both net stress and suction. The NCL’s either, for low suction value, has void ratio lower than the saturated NCL (associated with slope lower than the saturated NCL), or the NCL has void ratio higher than the saturated NCL (associated with slope higher than the saturated NCL) for higher suction value.

Total Suction Measurement of Unsaturated Artificial Gypsified Soil Using the Chilled-Mirror Hygrometer Technique

Qasim A.J. Al-Obaidi; Tom Schanz

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 359-374

Total suction is the sum of the matric and the osmotic suction of the soil. Various methods are used to measure the total suction of the soil. One of the methods is the chilled–mirror hygrometer technique. The chilled-mirror device employs a dew-point procedure, which is one of the most accurate and valuable methods for measuring total suction in the mid- to high- total suction range.
The effect of the percentage of gypsum on the total suction estimation for a gypsum-sand mixture has been investigated rarely in the past. In this paper, the total suction is determined for soil specimens containing different percentages of gypsum additive mixed with Silber sand. The soil specimens were prepared at different initial conditions of density and degree of saturation in order to investigate a wide range of physical soil properties. The test results showed that an incremental increase in the percentage of gypsum and degree of saturation of a soil mixture caused a reduction in the measured value of total suction, while an increase in the initial dry density caused the measured total suction to remain almost unchanged. No constant trend is observed with respect to the effect of the curing time on the measured total suction.

Effect of Recharging Primary Treated Domestic Wastewater on the Soil Characteristics

Ahmed Hazim AbdulKareem

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 375-387

A study was carried out to investigate the effects of recharging primary treated domestic wastewater on soil characteristics by special recharge-recovery method developed and practiced in the laboratory working model. Recently, the amounts of wastewater are sharply increasing and the kinds of pollutants are also varied as the world wide industry is being developed incessantly. The subbase soil is brought from Jerashi quarry, northeast of Ramadi and placed in model which is made from plexus glass with dimensions (1.1 m * 1.1 m * 0.6 m). Wastewater characteristics, main soil and soil samples after recharging of wastewater 330L, 420L, 510L, and 600L, for one time every seven days and comparing the means for soil chemical characteristics before and after experiment. Soil reaction (pH), electrical conductivity (EC), organic matter (OM), chloride ions (CL), sulphate content (SO3), gypsum content (GC), total dissolved salt, (TSS), and total dissolved solids (TDS). The soil-aquifer system (SAT) can be used efficiently as a wastewater treatment plant. After recharging wastewater, there were slightly increase of pH and OM in comparison with EC, CL, SO3, GC, TSS, and TDS which might cause problems in the long term if the land was used for construction purposes.

Behavior of Experimental Model of Piled Raft Foundations on Clayey Soils

Mahmoud AL-Qaissy; Hussein H. Karim; Mudhafar K. Hameedi

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 288-408

Piled raft foundations are a geotechnical composite construction consisting of three elements: piles, raft and soil. In the design of piled rafts, the load is assumed to be shared between the piles and the raft. Therefore, this may improve the ultimate load capacity and reduce settlements in a very economic way as compared with the traditional foundation concepts. Due to the development of structures that use piled rafts as a foundation system, an extensive experimental study was performed by two different scale models with the same L/Dp (Embedment length to pile diameter ratio) and L/Br (Embedded length to raft width ratio Br) to achieve the scale effect and plane stress condition for the large scale model and plane strain condition for the small scale model. The load carrying capacity of the piles and raft have been studied and presented as load-settlement illustrations. From a comparison between the two models of the experimental work, it is found that the effect of scale cause an increase in carrying load of piled raft with increasing the number of piles. It was found that the percentage of the load carried by raft to the total applied load of the experimental model in the case of four piles with raft is ranged between 60.6 - 64.8 %.

A Comparative Study between Piled-Raft and Two Soil Improvement Techniques

Maki Jafar M. Al-Waily; Ala; a Ali S. Al-Ta; Suad Mohammed H. Al-Janabi

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 409-421

This investigational study was directed to establish the correlation between piled raft foundation and two soil improvement techniques, stone columns and lime columns to evaluate the bearing improvement ratio BCR for the soft clay soil with three values of undrained shear strength, 8 kPa,10 kPa and 12 kPa. The 12 model tests was conducted in the present work, three models of untreated soil, three models of soil with piled raft, three models of soil treated with stone columns and three models of soil treated with lime columns. The container used in experimental works was made of steel with plane area of 500 mm * 500 mm and 500mm in height. The thickness of soil sample inside the container was 400 mm.
The study showed that the piled raft was more efficient in the bearing capacity improvement than the two soil improvement techniques. The bearing improvement ratio were 3.39, 3.27 and 2.78 in the three model tests of piled-raft for three samples of soil, respectively, while the lime columns provided the lowest values of the bearing improvement ratio were 1.64, 1.67 and 1.8 respectively.

Distribution of some Heavy Metals Pollution Caused byAl- Daura Refinery in the Surrounding Region

Riyad H. AL-Anbari; Mohammed M. AL-kaissi; Mohammed A. Al-Ameri

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 422-434

Due to the higher increase in the oil industry activities in Iraq, since there are a little information of the environmental status of the areas around the refinery locations, and the concerns of a possible environmental pollution that will cause health and life threats to living organisms, this study was carried out.To understand the status of heavy metals pollution in areas inside and surrounding Al-Daura refinery activities, (17) testing locations were chosen, ten locationsoutsidethe refinery and sevenlocationsinside it.One additional location was chosen in a rural (control) area, in the University of Baghdad, to compare between the heavy metals concentration in the study area and a sample from the rural area not affected by the pollution. The soil samples have been taken from (5 and 60 cm) depth from the top surface of the soil. Three samples were taken from each depth for each location to take an average of results.All the samples of soil were taken during the period from Dec/2010 to Feb/2011.The experimental work has been includes the heavy metals concentrations, such as Zinc, Nickel, Lead and Cadmium, have been measured at each selected depth for each testing locations.The results indicate that the mean concentration of Zn and Ni is (62.4 µg/g) and (100.5 µg/g) respectively and this valuesexceeded the mean allowable value by (Alloway, 1995 [2]; Kabata-Pendias and Pendias, 1992 [6]).The most concentrations of Zn, Ni and Pb, with some exceptions, accumulate at the top soil and decrease with the depth except Cd.

Experimental Study on the Behavior of Skirted Foundation Rested on Soft Clayey Soils

Mahmoud AL-Qaissy; Huda Muwafak

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 434-443

The purpose of this study is to investigate the behavior of skirted strip model footing founded on beds of soft clays and to evaluate the improvement values in bearing capacity. A series of laboratory model tests were conducted to determine the optimal vertical capacities of skirted foundation within different skirted embedded depth (D/B) ratio (embedded depth to footing width) ranged between (0.0-2.5). The results of model tests based on the load-settlement behavior, revealed that the insertion of skirt structure into the soft clayey soil has a clear increasing the magnitude of bearing capacity with increasing (D/B) ratio according to the lateral confining pressure as compared with the soft clay state without lateral confining (D/B = 0). As a principal part in this study is to knowledge the adequate skirts embedment depth for improvement the ultimate bearing capacity value. It is found that the appropriate skirted embedded depth as the skirt depth to foundation width of 0.5 (D/B=0.5).

Improvement of Soft Soil Properties Using Dynamic Compaction with Stone Columns: Case Study (AL-Mualla Site-Yeman)

Suhail I. Khattab; kaythar A. Ibrahim; Amina A. Khalil

Engineering and Technology Journal, 2013, Volume 31, Issue 20, Pages 1-10

Dynamic compaction was considered as one of a deep compaction method which was used to improve the soil properties. Also it was used to save cost and time in comparison with other methods.
The aims of the present studies were to study the improvement and changes in soil properties that occurred in Al-Mualla Site-Yeman using dynamic compaction. The site soils classified as Silty Sand with small boulder with Clayey-Silt layer extend from 2.2 m to 3.2 m deep.
Cone penetration test was done before and after treatment process using dynamic compaction for approximately the same two tested boreholes. As a result of the treatment and based on how the soil properties changes, the soil was divided into three zones varied from (1.2 to 5, 5 to 8.6, and 8.6 to 11 m) respectively. Field results show that there was increased in bearing capacity from 80 kN/m2 to 110 kN/m2. Cone penetration test for the first zone increased from (1.2 to 8.35 MN/m2), and from (2.43 to 7.07 MN/m2) for the first and third zone respectively at the first tested borehole and also from (2.05 to 6.8 MN/m2), and (2.14 to 5.0 MN/m2) for the second tested borehole. Also can be noted that the cone penetration test results decreased from (5.22 to 3.77 MN/m2) for the second zone at the first tested borehole, with no change was happening for the second tested boreholes.
Also the effect of soil improvement on the settlement value and effective stress distribution was studied theoretically using finite element package PLAXIS2D program. The result shows that the improvement in soil properties leads to decrease in the expected settlement.