Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 31, Issue 19

Volume 31, Issue 19, November 2013, Page 1-215

Water Infiltration Characteristics for Artificial Lake in Bahr Al-Najaf

Namir K. S. Al-Saoudi; Mohammed Sh. M. Al-Shakerchy; Salam A. Abbas Al-Janabi

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 1-12

Al-Najaf is one of the important cities in Iraq due to its high spiritual and religious reputation that attracts Moslems from different parts of the world to visit the holy shrine of Al-Imam Ali (peace be upon him). The city of Al-Najaf and particularly Bahr Al-Najaf area, is expecting a number of large scale construction activities, among these development activities are the planning of a new tourist city called Sayf Thulfiqar city. Sayf Thulfiqar city is planned to be the largest tourist city in Iraq. The area of the proposed tourist city is about 63 hectares, consists of an artificial lake 1000m long surrounded by twelve towers and a number of small dwellings. This lake is considered as a big challenge in planning, construction, and sustainability. The challenging points primarily are the sources of water required to fill the lake, infiltration characteristics of the soil at site, weather conditions, etc.
The present paper focuses on investigating the rate of water infiltration through the base and side walls of a pit with dimensions 3m by 3m and 0.5m in depth excavated and filled with water in the location of artificial lake. The process of filling was repeated several times with full observation and continuous field measurements. The results revealed some useful characteristics and correlations regarding the infiltration of water of artificial lake in Bahr Al-Najaf.

Bearing Capacity of Shallow Footing on Compacted Dune Sand Underlain Iraqi Collapsible Soil

Bushra S. Z. Albusoda; Rusul S. Hessain

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 13-28

Gypsies Soils are disturbed in many regions in the world including Iraq, which cover about (30 %) of the surface area of the country (Al-Dulaimi, 2004). Existence of these soils, sometimes with high gypsum content, caused difficult problems to the buildings and strategic projects due to dissolution and leaching of gypsum by the action of water flow through soil mass. In this research, a new technique is adopted to investigate the performance of replacement and geosynthetic reinforcement materials to improve the gypseous soils behavior through experimental set up manufactured locally specially for this work. A series of tests including dry and wet tests were carried out using steel container (600×600×500) mm. A square footing (100×100) mm was placed at the center of the top surface of the bed soil. The results showed that the most effective thickness for dune sand layer with geotextile at the interface, within the tested range, was found to be almost equal to the width of foundation. Therefore, under this depth, the soil was reinforced with geogrid and geotextile. The bearing capacity increases to (1.5-2.0) time under concentric loads and (2.5-3.0) under eccentric loads after replacement and reinforcement of gypseous soil.

Effect of Stress Level on Behavior of Bored Piles Embedded in Medium Sandy Soil

Kais T. Shlash; Mohammad A. Al-Neam; Saif I. Akoobi

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 29-43

In this paper investigation in the end bearing and shaft resistance of bored piles embedded in medium sand and subjected to axial load for wide rang of stress levels starting from laboratory dimensions and go toward field dimensions were made by utilizing the finite element method. The soil is modeled using hyperbolic soil model with empirical equation account for reduction of angle of internal friction Ø with increase in stress level while the bored pile assumed as a linear elastic material. It was found that the stress level has a significant effect on pile’s behavior and the small scale model in laboratory dimension not represent the real behavior of pile in field dimensions and if the results from such dimensions are adopted, it will lead to overestimate of bearing capacity factor Nq. Also, the effect of embedment ratio (L/D) on pile’s behavior is examined in this study and the results showed that the embedment ratio (L/D) increases the bearing capacity factor Nq up to a certain length beyond it the effect of embedment ratio (L/D) diminished.

Simulation of Behavior of Plate on Elastic Foundation under Impact Load by the Finite Element Method

Mohammed Y. Fattah; Mohammed J. Hamood; Sura Amoori Abbas

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 44-58

Transient response and vibrations of an elastic plate resting on sandy soil are presented. Plates are commonly used structural elements and are subjected to wide variety of static and dynamic loads. Such studies are of particular interest in analytical investigations related to structural foundation on soil media. The influence of impact induced high strain-rates within the structure, which causes property changes in all used materials, has to be regarded according to experimental results.
The main objective of the present paper, using the finite element approach through ANSYS program is the simulation of the dynamic response of the foundation under impact load. As a case study, previous experimental work included application of a dynamic load generated by dropping a steel ball (38.1 mm in diameter, 2.22 N in weight) from a height of 609.6 mm onto an aluminum target plate (203.2 mm in diameter, 12.7 mm thick) placed on top of a sand medium. The impact load is defined as a product of the loading magnitude and a time varying function which is assumed to be a Hanning's function for a monopeak, smooth-shaped curve. The problem is discretised by using four types of elements; Solid 45 to model the soil, Shell 63 to model the aluminum plate and Target 170 and Contact 174 are used to model the contact between the plate and soil. Shell 63 (elastic shell) has both bending and membrane capabilities.
It is noticed that the finite element analysis agrees well with the experimental results throughout the entire range of behavior, and the difference in the ultimate displacement is about 6.2%. It can be concluded that ANSYS program is well suited for impact analyses of soil and structural dynamics problems in the non-linear range.

Effect of Loading Duration on the Parameters Obtained from Consolidation Test

Mohammed A. Mahmud Al-Neami

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 59-69

Consolidation properties of clay soils are evaluated in the laboratory using the one-dimensional consolidation test. The one-dimensional consolidation testing procedure was first suggested by Terzaghi (1925). In this procedure, the load on the specimen is applied and usually kept for 24 hours. After that, the load is doubled. Therefore, the duration of this test may continue at least 1 week and this duration is unpreferable for traditional purposes if the work is huge.
In this paper, decreasing of applied loading test time has been studied through a new proposed time for applied loading. The results of a new time procedure have been compared with standard (conventional) Oedometer tests that they have been carried out on remolded samples of clay to investigate the difference percentage if quick tests are adopted instead of long tests.
The comparison shows that the compression index increases with the increase test time, therefore, the compression index must be modified (use 1.1 Cc) when employed to calculate the settlement of soil. Also, the elapsed time of test is significant to the determination of swelling index. So, the test time of applied load should be not less than 2hrs.
The results show that two hours are enough to reach 90 % consolidation (t90). The values of pre-consolidation pressure predicted depending on the results of quick test are always smaller than those predicted depending on the results of conventional test results. Finally, two hours LID is enough for calculating the coefficient of permeability depending on the parameters obtained from consolidation test.

Characteristics of 2-D Electrical Resistivity Imaging Survey for Soil

Hussein H. Karim; Imzahim Abdul Kareem Alwan; Mohammed A. Al-Neami

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 70-89

The present work is aimed to show the efficiency of 2-D Electrical Resistivity Imaging (ERI) in probing the subsurface soil for site investigation, in addition to highlight some capabilities and characteristics of the sections acquired by 2D-ERI survey. In the field survey, where the University of Technology site is chosen for such investigation, ERI technique has been used implementing three common arrangements (Wenner, Wenner-Sclumberger and dipole-dipole). Different resolving powers have been obtained for the used arrays. Wenner-Schlumberger array gives moderate number of possible measurements and has a median depth of investigation of about 10% larger than that for the Wenner array. It is moderately sensitive to both horizontal and vertical structures, thus it might be a good compromise between the Wenner and the dipole-dipole arrays. Good agreements have been obtained between the stratigraphic columns of the site with the inversion models using the different arrays. The distribution of resistivity of the inversion models for the study site reflects the highly inhomogeneous subsurface soil with a wide variation of soil resistivity at different depths.

A Study of the Behavior of Shell Footings using Finite Element Analysis

Adel A. Al-Azzawi

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 90-102

In this research, the conical shell foundation is investigated. The two components of the interacting system; the soil and the shell foundation, are modelled using the finite element method. In this study, 15-node isoparametric triangular axisymmetric elements with two degrees of freedom at each node are used to model the shell and soil. The soil-structure interaction between the footing and the supporting medium are modelled using interface elements. Comparison between the results obtained by the present analysis and those obtained by other investigations are made. The present analysis shows satisfactory results when compared with those obtained by other studies with largest percentage difference of 14% in the value of the ultimate load. Parametric studies have been carried out to investigate the effect of some important parameters on the behaviour of shell foundations. Three parameters are considered which are: semi-vertical angle, footing embedment and edge beam.

Assessing and Evaluating the Effect of Organic Matters on Clayey and Silty Soil Stiffness Properties

Aqeel Al Adilil; Kawther Y.H. Al-Soudany

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 103-119

Construction of building and other civil engineering structures on weak or soft soil is highly risky because such soil is susceptible to differential settlements, poor shear strength, and high compressibility.Organic soils are difficult to deal with due to their particular characteristics such as high compressibility and poor strength and, as a consequence, criteria based on common mineral soils may not generally be applied to them. The objective of this research is to investigate and assess adding different percentages of organic matters on soil stiffness, from laboratory experimental work, and to investigate the effectiveness of animal disposals and plants pieces (leaves) ontwo soil types.
Hence, in the present research, mixed organic materials have been used, and it was randomly included in to the soil at four different percentages of organic content, i.e. 5, 10, 15, and 20% by the weight of two main raw, silty soil and clayey soil. The research revealed from the laboratory tests that when organic mattersincreased the stiffness of both clayey and silty soil were reduced, and the reduction were from 16.5% to about 61% with 5 and 20% adding percentage of organic matter respectively. While the liquidity and plasticity increased from the reference soil (without organic materials) as well as the swelling index increasing for the two types of tested soils. Moreover the research indicates the percentage of organic contents played an important role in the development of the vertical displacement of the clayey and silty soil under loading.

Interaction between the Existing and the New Constructed Tunnels

Nahla M. Salim

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 120-135

The effect of construction new tunnel on nearby tunnel was investigated using finite element software program SIGMA/W. Two methods of excavation were used, one using one stage in construction of tunnels and the other using eight stages of excavation. The analysis also carried out to study the effect of nearby tunnel on existing tunnel by varying the pillar width (W), using W equal to 3, 5, 7 and 12 m. The results show that, using stages in construction of tunnel has no significant effect comparing with one stage. The study indicates that there is significant effect of position of new tunnel on the existing tunnel.

New Chemical Stabilizer Effect on Plasticity of Lateritic Soil Properties

Yahiya K. Atemimi; Fauziah binti Ahmed; Yuones Bagiry; Mohd Ashraf Mohamad Ismail

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 136-145

The lateritic soil that has high content of iron oxides and aluminum hydroxides and low proportion of silica is widespread in the tropical and semi-tropical countries. Lateritic soil as available materials in these areas utilized in different civil engineering applications as roads, canals, earth dams, railways, building, … etc. These applications are depending in a majority on soil classification in design the construction on this soil type. One of the important parameters in classification of soil is an Atterbage’s limits are used in definition of soil type and its strength. Due to increase in population caused an increase in construction to demand the facilities of this growth, therefore the desired soil decrease depend on used and the undesired soil available. Soil stabilization utilized to improve the undesired soil properties by a different technique to achieve the design requirement. Chemical stabilization becomes one of the best solution to soil problems depend on economic and time save. New chemical soil stabilization used is named (NBT II) in this study to exam the effect on plasticity soil properties. Different percentages and different curing time test conducted on lateritic soil to evaluate the range of effect and also examined the effect of plasticity on dry density. The results show decrease in liquid limit with increase in NBT II and then beginning to increase with stabilizer percentage increase the reduction about 11% at 28 days curing, plastic limit increase about 6% at the same time and plasticity index decrease 80%. The results also show the inverse relationship between maximum dry density and plasticity index.

A Comparative Study between the Historical Stones of Al-Namrud Monument in Iraq and the Fresh Stones Extracted from its Quarry Using TGA and XRD Analysis

Harith E. Ali; Suhail A. Khattab

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 146-158

This study implies a characterization and comparison between the historical limestone and gypsum stones of Al-Namrud or (Calah) monument which located in the north of Iraq 37 km to the eastern south of Mosul city (eastern bank of the Tigris river) and those (fresh) extracted from Al-Mur hill which suppose to be its quarry (according to the historicity and archeology references). The aim of this study is the conviction of the veracity of these references depending on a number of complementary engineering techniques. These tests include physicochemical and mineralogical properties of fresh and historical stones , textural arrangement of particles (porosity and pore size distribution) by mercury porosimetry tests; water transfer properties by water retention curve test; bulk density at dry state by hydrostatic weighing method have been executed . Also a comparison between the fresh and historical stones has been carried out by X-Ray Diffraction (XRD) and Thermo Gravimetric Analysis (TGA). Results shows for the historical stone higher porosity and different pore size distribution, water transfer properties in comparison to the fresh stone .Also, a high match in the compositions of stone materials of both historical and fresh one reflect the rightness of the historicity and archeology references and their consideration of being Al-Mur hill the quarry of Al-Namrud monument.

Assessment of Bearing Capacity of Subbase Contaminated with Kerosene

Zeena W.Abbawi; Kawther Y.Al-Soudany; Makki K.Al-Recaby

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 159-172

The present paper is focused towards evaluation bearing capacity of subbase layer which is contaminated with Kerosene.
Seven series of model tests were performed using steel container (500*300*300mm). The bed of subbase was compacted in three layers inside the container; each layer was 100mm in depth. Circular footing 65mm in diameter resting on the bed of subbase were loaded incrementally up to failure. Different percentages of Kerosene (0%, 5%, 12% and 20%) were added, the first series consists of uncontaminated soil layer, the second series covers the model tests with added (5%, 12% and 20%) to the top subbase layer and third series covers the model tests with added (5%, 10% and 20%) to the top and second subbase layers. Each percentage was added separately. The results showed increase in ultimate bearing capacity; with increasing of Kerosene content up to 5% then a decrease with further increase of Kerosene content.

Volume Change Measurements for Unsaturated Soils in Triaxial Equipment with Double Wall Cell

Muayad A. Al-Sharrad; Domenico Gallipoli; Simon J. Wheeler

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 173-184

The paper gives a brief description of double wall cell triaxial equipment for testing soil samples under unsaturated conditions and presents results of some of the calibrations necessary to achieve accurate measurements of inner cell water volume, pore water volume, pressure, load and displacement. The calibration of the measurement devices showed linear relationships between the raw readings and applied values with the regression constants differ from 1 and 0. The result of apparent volume change calibrations showed significant correlation between cell water volume fluctuation and temperature fluctuation inside testing room. A correction to the measured volume was therefore required to reduce the effects of long-term temperature fluctuation on the measured volume. Investigation of the accuracy of volume change measurement with the double wall cell showed excellent matching between the inner cell volume change and pore water volume change under saturated conditions, indicating the high reliability of the double wall system for apparent volume change measurements.

Consolidation Behavior of Two-Pile Group System under Different Loading Condition using the Bounding Surface Model

Qassun S. Mohammed Shafiqu; Maarib M. Ahmed

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 185-202

In this paper, soil-water coupling analyses with finite element method are conducted to investigate the long-term displacements of two-pile foundation installed in saturated cohesive soils under different loading condition. As constitutive model for clayey soil, elasto-plastic bounding surface model is considered, which is a sophisticated elasto-plastic model for normally and over consolidated soils. The influence of loading intensity and consolidation process are considered carefully. The analyses showed that the elasto-plastic bounding surface model may provide a realistic stress distribution within the soil mass around the piles. Also as conclusion of a series of analyses, the followings are clarified; 1) the long-term behavior of two-pile group system; 2) the mechanism of how the space between piles affects the long-term displacements.

Prediction of the Safety Factor of Slope for the Two Cohesive Layers

Husain Ali Abdul - Husain

Engineering and Technology Journal, 2013, Volume 31, Issue 19, Pages 203-215

Analysis of slope stability focus, on determining the value of the safety factor (Fs) which is mean the ratio between the shear strength of the soil to the developed shear stress on a certain slip surface. Engineers are interested with the minimum value of FS which is obtained by analyzing some trials of slip surface. In the present work, slope of two cohesive layers of the same unit weight is studying. About (100) different problems are analyzed using the package (Slide 6.0). These problems takes into account the impact of some factors on the minimum value of FS. These factors are: the ratio between the cohesion of the top layer to that of the second one (cu1/cu2) which is denoted by (Cr), the ratio between the height of the top layer to that of the slope (H1/H) which is denoted by (Hr) and the angle of the slope (B). The results of the analysis are normalized as a stability number (Ns).A regression analysis then conducted to these problems using well known package (STATISTICA). The accuracy of the suggested model is tested by R2. The value of R2 of model to predict stability number is about 0.982.