Mohammed Shakir Mahmood Al-Shakerchy

This paper presents laboratory experiments on the effect of matric suction on the compressibility of unsaturated gypsum sand soil. The samples were obtained from Al-Najaf city in Iraq with gypsum contents of 14%, 22%, and 29%. Two series of laboratory tests were conducted. The first one is loading-path likes when a building is constructed on these soils in a specific degree of saturation (specific matric suction). Four matric suctions were adopted; 100, 60, 30, and zero percentages of initial matric suction under two confining stresses; 100 kPa and 200 kPa. Also, two saturated tests (CD) were performed under the aforementioned confining stresses. The second method is wetting-path, likes when a structure has been constructed and the degree of saturation of a foundation soil increases (decreasing in matric suction). The results from both paths revealed that the volumetric strains were increased by decreasing the matric suction and increasing the gypsum content.. ARTICLE HISTORY

This study presents the impact of chloride ion present in the soil in contact with reinforced concrete in the initiation of corrosion of steel reinforcement. The factors affecting the corrosion process due to the penetration of chloride ion from chloride bearing soils in contact with concrete specimens, representing different reinforced concrete members, were studied. The results proved that there exists a threshold limit for the concentration of soil-borne chloride ion, to initiate the corrosion. The value of this limit was related to the thickness of the concrete cover, concrete grade, besides the type of exposure (number of sides exposed to chloride attack). It was shown that the safe percentage of chloride ion in the groundwater and soil in contact with concrete was 2% in aqueous extract (0.4% in soil) when the thickness of the concrete cover was not less than 50 mm. This proportion could reach 6% in aqueous extract (1.2% in soil), when the cover thickness was not less than 75 mm, or when the concrete possessed a 35 MPa compressive strength as well as exposed on one side only. Consequently, special limitations for the permissible proportions of chloride ion in soils in contact with reinforced concrete members should be established by design codes.

Gypsum is a soluble material, and it is one of the problematic components in the soil in the west of Iraq. Al-Najaf is one of the governorates in Iraq which suffers from the gypsum content in different levels. The soil of the city is mainly sand-sized particles bonded by different percentages of gypsum. The main problem of this component is the dissolution upon the wetting process in unsaturated conditions. This paper investigates the effect of decreasing the matric suction (wetting) on soil deformation under a specific stress level. A modified Oedometer setup is used to perform the tests, including the application of air and water pressures up to achieve the specific matric suctions. The investigation includes three matrics suctions of (50, 20, and 0 kPa) and each under three net normal stresses of 221 kPa, 442 kPa and 885 kPa respectively. The soil specimens are remolded to 95% of the maximum dry density from the proctor test. The results revealed that the highest value of collapse potential (CP) is under the stress of 221kPa. The greatest part of the CP is achieved before the saturation of the soil. This issue must be considered in the analysis and design of the foundation in unsaturated gypseous sandy soils as an improvement issue.

This paper is an extension and continuation of an earlier work by the authors on the phenomenon of meandering in Al-Abbasia reach located in the middle of the Euphrates river, Najaf governorate in Iraq. The authors have developed several power functions models and models depending on dimensional analysis and Buckingham π-theorem for modeling and predicting the hydraulic geometry of the selected reach. The paper employs the nonlinear regression technique for developing mathematical models for computing the width and mean depth of the reach depending on its hydraulic characteristics. This paper is part of an M. Sc. thesis carried out in 2014. The developed relationships are straightforward to be applied in design and analysis with results of high acceptability; the reach width (W) model is with R2 of 0.97 while the reach mean depth (Dm) model is with R2 of 0.93. Different statistical methods have been utilized to compare among the different models. The results reveal that the non-linear regression models are the best models to correlate the different characteristics of the reach.

During the last decade, Iraq experienced gradual shortage in the volume of water flowing in Tigris and Euphrates rivers due to natural and environmental effects. Shortage of rainfall in the basin areas, lack of snow cover over the catchment areas and reduction in water released downstream from dams constructed in the riparian state in Turkey are the major causes of the current shortage. The present paper focuses on the possibility of constructing an infiltration basin in Najaf governorate, to benefit from the recharged overflow water in agricultural areas and to sustain ground water. Field and laboratory geotechnical and hydrological tests were performed in selected agriculture area in Bahr Al Najaf, including field infiltration, field permeability and soil classification. The analysis of the tests revealed that the development of design charts and equations that facilitate the design process of infiltration basin. Accordingly the selected site is found to match with the requirements of the infiltration basins, and the recommended area of the infiltration basin is 9% of the irrigated area with depth of 0.35m.

Most of the hydraulic geometry relationships derived under premises that there are direct or indirect relation, at least statistically, between meander geometry characteristics include width, depth, cross sectional area and some hydraulic variables as discharge and velocity. The hydraulic variables satisfy for rectangular channels the continuity equation. The authors developed four power functions for predicting the hydraulic geometry properties of Abbasia reach, in the middle of the Euphrates river, Najaf governorate. These power models with certain coefficients(a, c, k and p) and exponents (b, d, m and n). The recent work is to perform the continuity of the results on the predicted models in previous paper. The results indicate that there was an remarkable degree of consistency for both coefficients and exponents.

During the last decade, Iraq experienced gradual shortage in the volume of water flowing in Tigris and Euphrates rivers as a result of many natural and environmental effects. Shortage in rainfall in the basin areas, lack of snow cover over the catchment areas and reduction in water released downstream from dams constructed in the riparian state in Turkey are the major causes of the current shortage. The present paper focuses on the possibility of constructing an infiltration basin in a rural area in Najaf governorate, to benefit from the recharged overflow water in agricultural areas and to sustain ground water. The design of the infiltration basin wasdepended on field and laboratory geotechnical and hydrological tests in Bahr Al Najaf agriculture area. These tests included field infiltration, field permeability and soil classification. Accordingly the selected site is found to match with the requirements of the infiltration basins. Design charts and equations were developed to facilitate the design process of infiltration basin starting from the estimation of runoff water and ending with dimensions of the basin. The recommended area of the infiltration basin is found to be 5.6% of the irrigated area with depth of 35cm.

The hydrologic cycle describes the continuous movement of water above, on, and below the surface of the Earth. The issue of water is one of the most important matter due to a lack of water resources with hot and dry climate. Iraq is vulnerable because of its reliance degree up to 90 % on the water of the Tigris and Euphrates that originate from Turkey. This paper focuses on current and distribution of the surface and ground water resources in Bahr An-Najaf basin in Najaf, Iraq. The results indicate that the total volume of water quantity is about 180 Mm3 with monthly variation. Surface water is about 77% of the total water volume and the groundwater is about 21%.

Most of the hydraulic geometry relationships derived under premises that there are direct or indirect relation, at least statistically, between meander geometry characteristics and some hydraulic variables as discharge and velocity. The authors, based on-a-site investigation on Al-Abbasia reach, in the middle of the Euphrates river, Najaf governorate, developed power functions (four models). The study-reach is about six kilometers, it is divided into twenty one cross-sections. These sections represent the meanders and bends in the reach. The recent work is to develop models depending on dimensional analysis and Buckingham Pi theorem. These models are correlate the river width and mean depth with other geometry and hydraulic characteristics. The statistical comparison of the different methods illustrate that the method of dimensional analysis gives higher results in width model comparing with method of power function and lower in mean depth, but acceptable.

Meandering phenomenon is a bend in the course of a stream, usually occurring in a series. The river plan form movement is a process in the river that is associated with soil erosion on a riverbank on one side is accompanied by a sedimentation on the other side. Al-Abbasia reach, in the middle of the Euphrates river, Najaf governorate, was selected to investigate the meandering process. The study-reach is about six kilometers, it is divided into twenty one cross-sections. These sections represent the meanders and bends in the reach. Power functions were used and applied for modeling and predicting the hydraulic geometry (4 models) for the selected reach and comparing with other models in previous studies. The recent models aresuitableto be used in the natural channels design, hydraulic management and restoration.

The demand for water in the developing world, of which the Middle East is a part. In Iraq, the water consumptions are divided for the different fields, mainly, irrigation, industry, domestic. By using the management of water resources, we can reduce the dependence on water releases from Tigris and Euphrates that originate in Turkey. This paper focuses on current water consumption and distribution in Bahr An-Najaf area (251 km2), Najaf, Iraq in the current state. The results indicate that the consumption of agriculture of crops is the highest, then residential and industrial consumption and the lowest water consumption is livestock drinking.

The word “Khan” refers to the place where visitors to Najaf city will rest for few days. Historically visitors with their animals, as the only means of transport, usually come to Najaf city in certain religious occasions, rest and settle down in Al_Shelan Khan. The Khan was constructed in 1895 by the governor (Wally) Muhammad Mueen Aga during the last years of the Ottoman Empire. The Khan is distinguished by its architectural design and the configuration of the types of columns and arches. The structure has an overall area of 1500 m2 consisting of two floors and three basements located at different places in the structure layout. The foundation of the structure is strip type extended approximately 5.5 m below ground level. Bricks of dimensions 22cm *10cm*4,5cm are the building units with a mixture of juss, lime as binding material. The paper focuses on the overall structural skeleton of the Khan and on the analysis of foundation system.

يعاني العالم اليوم، بشكل عام، والعراق بشكل خاص مشكلة كبيرة في الموارد المائية تتمثل في شحتها، حيث تضررت مساحات زراعية كبيرة وظهر التصحر، وبالتالي تسببت في الكثير من المشاكل الانسانية. يتم التخطيط المائي من خلال معرفة التوازن بين الاستفادة واستدامة المصادر خلال فترة معينة، حيث تحتاج هذه الموازنة الى ادارة الموارد المائية والتي يتم من خلالها تحديد الكمية، النوعية، المراقبة، والاستخدام، وبذلك يتم وضع ضوابط خاصة للاستدامة والاستفادة ضمن مخططات إدارة المياه. ترتبط درجة الاستفادة بشكل وثيق بإدارة البنية التحتية. وفي النجف الاشرف، هناك اهمية متزايدة للتخطيط المائي فيها مع اقامة نظام ناجح لإدارة المياه، والبحث عن مصادر مياه إضافية، فهي في الوقت الذي تساعد على ديمومة تلك الموارد، تكون عاملا مهما في التخطيط الجيد لمستقبل المدينة على المستوى العمراني، الانتاجي ومنها الزراعي، ... في البحث الحالي، يتم استعراض مجموعة من التجارب العالمية في ادارة المياه في مختلف النواحي ودراسة مشكلة المياه في النجف الاشرف من حيث تحديد اسباب المشكلة ومناقشة الحلول المقترحة لها.

The present study is summarized all the geotechnical data available about Al-Najaf city from previous site investigation reports performed by NCCLR branch of Babylon followed by an extensive statistical analyses. The results of the statistical analyses provide representative values for different geotechnical parameters for the city including the soil composition (sand/fine ratio), the shear strength parameters, SPT results, and gypsum content. The statistical analyses, based on program SPSS-release 11.0.0, revealed some important models that represent the strength parameters () as a function of the other three parameters sand/fine ratio, gypsum content, and N-value for the different sectors of the city. The overall statistical analysis for Al Najaf city after dividing the city into two main areas, the old city and the new extensions, limiting the range of different characteristics of the site in the main areas, such as, the type soil is about 70 % sand, gypsum content is < 6 % with depth below 2.0m, the N-value is over 50 blows within the depth below 2.5m.

The infiltration characteristics of the soil are an important component of the hydrological conditions. They are one of the components of the water balance and are necessary to describe the runoff response by a runoff model, in addition to describe the effect of water movement on the changing of the soil properties within infiltration. The present work emphasis on the characteristics of the infiltration by using laboratory model. This model is performed on the remoulded sample of specific density for different heads of water, 10, 20, and 30cm. The results revealed that there are significant effect of the water head with high interaction of the wetting conditions of the soil sample. A comparison was made with the results of field infiltration work, made by Mohammed Sh. Al Shakerchy, 2006. A statistical analysis was made to develop a relationship among the different studied parameters and between the field and laboratory works.

Al Najaf is one of the important cities of Iraq due to the high religious attraction for Moslems. It is expected to have a huge development program in the coming few years. Groundwater (sub surface water) is one of the essential problems of city soil that affect the durability of the different structural projects. These problems divided into two main groups, first, problems during construction below the groundwater level, and second, problems during the life of the project (with changing the soil properties by groundwater movement). The present paper discuss, first, the reasons leaded to accumulation of groundwater in the city and second, the problems of the groundwater in the city soil with presenting the suggested solutions to avoid expected failure of the structures.

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