Papers by Mohammed S H A K I R Mahmood
Uncertainty of Pile Design Capacity in Gypseous Sand Soils
Journal of Geotechnical Engineering, Nov 2, 2018
Uncertainty of the design is a problem comes out due to the alteration of the soil properties. De... more Uncertainty of the design is a problem comes out due to the alteration of the soil properties. Depended on the available geotechnical soil properties of Al Najaf city, a study program is prepared to investigate the effect of the alteration of some soil properties, such as unit weight and angle of internal friction, on the design bearing capacity of a bored pile. The soil of the city is suffering from soluble salts, such as gypsum and lime. These salts, by soaking and leaching processes, cause negative alteration of soil properties leads to negative analysis and design of the structures, such as piles for bridges and buildings. The results of the study give a view on the effect of alteration of mentioned parameters on the design of pile in addition to the length and diameter of pile. The most effective parameter was the soil angle of internal friction (F) for different studied parameters.
Geohydrological Investigation of a Lake: Case Study of Lake of Sayf Thulfiqar
A reservoir is defined as an enlarged natural or artificial lake. A reservoir, also, means storag... more A reservoir is defined as an enlarged natural or artificial lake. A reservoir, also, means storage pond or using dam to store water. An artificial lake namely "Sayf Thulfiqar" is decided to be constructed artificially in the region of Bahar Al-Najaf in Najaf province in Iraq for storage and aesthetic purposes. The soil of the region is unsaturated above water table and it is mainly sand as classified according to USCS. The geotechnical properties are investigated through site exploration sampling. The hydrological properties of the site were examined and mainly are the rate of infiltration and permeability. The water balance of the lake is evaluated through the investigation of probable water resources and losses of water through evaporation and infiltration from the lake. The results illustrate that there is variation in hydrological properties with time. The permeability varied from 1.5 to 5.5 m/day, and mainly the loss of water is due to infiltration. For water balance ...
Assessment of Deformation Along the Roof of a Model Cavity
For study the stability of strip model footing on a cavity in soil and the mode of soil failure, ... more For study the stability of strip model footing on a cavity in soil and the mode of soil failure, a special device was designed and manufactured to measure the deformations of the roof of a model cavity located underneath a strip footing. The device consists of two parts, the first is a box with four deformation units and the second is simply an Avometer. The first part is inserted inside a cavity prepared in advance in a bed of compacted soil and a strip footing is fitted on the surface of the bed of soil. Load increments on the footing accompanied by continuous deformation measurements of both footing and roof of cavity revealed some interesting results about the mode of collapse in soil.
Quantity And Distribution Of The Current Surface And Ground Water Resources In Bahr An-Najaf In Iraq
International Journal of Scientific and Engineering Research
The hydrologic cycle describes the continuous movement of water above, on, and below the surface ... more 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%.
This paper shows the different in the volumetric strains between the Oedometer tests with differe... more This paper shows the different in the volumetric strains between the Oedometer tests with different soaking durations and the unsaturated triaxial tests. The disturbed samples were taken from Al-Najaf city in Iraq. All specimens have the same high gypsum content of 29 %. For Oedometer tests, the specimens are tested in the different soaking durations; the first is in natural moisture content then half hour, one week and two weeks. While in triaxial tests, a wetting induce has been conductive to estimate the volumetric strains under two stress levels (2.5 and 5 kg/ 2) with presence of matric suction in four levels; initial matric suction (ψo), 0.6 ψo, 0.3 ψo and zero ψ. The results from unsaturated triaxial tests indicate that the volumetric strains are increased as matric suction decreased and the trend of stress-strain curve became steep. While from Oedometer tests, when the specimen is soaked in natural and for a half hour, the volumetric strains are not significantly changed and close to the high matric suction. When the soaking time is increased to a one week, there is relatively increase in volumetric strains. But after two weeks soaking in Oedometer cell, the volumetric strains are very clear in increasing and close to the volumetric strains from unsaturated tests in low matric suction.
Characterization of collapsible gypsum sand soil with the presence of matric suction using a modified odometer apparatus
This study looks into the influence of matric suction on the volume change of gypsum sand soil in... more This study looks into the influence of matric suction on the volume change of gypsum sand soil in unsaturated conditions. The specimens were collected from Al-Najaf, Iraq, and included 14 and 29% gypsum. Three series of initial stress laboratory tests were utilized in a modified oedometer device. For each gypsum content, twelve remolded specimens were examined in unsaturated circumstances with the initial stress and applied stress using four matrices suction (30 kPa, 18 kPa, 9 kPa, and saturated state). Three tests were performed for each matric suctions with initial stresses, no initial load, 56 and 112 kPa, respectively. The findings exhibit a clear pattern of increase in the vertical strain as gypsum content rises and matric suction reduces under a variety of situations. The wetting process softens the gypsum components, which are significantly resulting in an increase in vertical strains.
Contamination depth prediction in sandy soils using fuzzy rule-based expert system
As a result of rainfall in large quantities, the leachate generated under the municipal solid was... more As a result of rainfall in large quantities, the leachate generated under the municipal solid waste (MSW) is increased, which leaks to the groundwater aquifers and pollutes it. Accurate evaluation of leachate leaks levels has long been regarded as a problem in Iraq due to a lack of reliable data and costly measuring costs. This work proposes a novel fuzzy expert system to predict the pollution status of the underground water in sandy soils. The expert system consists of two subsystems; fuzzy logic system and crisp logic system. The expert system is trained using a data set developed by finite element analysis of sandy soil subjected to contamination materials.
This paper investigates the water volume changes in gypseous sand soils within the change in matr... more This paper investigates the water volume changes in gypseous sand soils within the change in matric suction and under different stress levels. The present research aims to examine water entry into the soil with different matric suction under different levels of constant net normal stress (221, 442, and 885 kPa). The soil sample is collected from Al-Najaf city, Iraq. The main soil of the city is sand with different percentages of gypsum at different locations and depths. These experiments revealed a clear relationship between decreasing the matric suction (wetting)
and changing the gypseous soil structure, i.e., increasing the void ratio, and this behavior also depends on the net stress level. With the demolition of the voids under high-stress levels, there is a decrease in water volume change at zero matric suction (saturation). A comparison is made
between the predicted soil water characteristics curve (SWCC) for the soil with the investigated values. The results show a shifting, which may be due to the accuracy of the curve fitting or/and the effect of the loading and gypsum content. This new understanding should help improve
predictions of the impact of the load, gypsum content, and time.
Collapsible soils are present in arid and semi-arid regions in an unsaturated state and are consi... more Collapsible soils are present in arid and semi-arid regions in an unsaturated state and are considered to be one of the problematic soils that face engineering and geotechnical challenges. They are regarded as sensitive soils where their structure and engineering properties change upon wetting (leaching or soaking). The wetting leads to a break in the bonds between the soil particles (salts or clay) and a decrease in the suction power that binds the soil particles together. Large settlement occurs and thus causing problems for the buildings and facilities constructed on them. Recognizing the properties and characteristics of collapsible soils is very important in order to know how to deal with them to avoid unnecessary financial losses and problems. This paper gives an overview of collapsible soils behavior and prediction in many aspects.
Prediction of the contamination track in Al-Najaf city soil using numerical modelling
IOP Conference Series: Materials Science and Engineering, 2020
Leachate generated from Municipal Solid Waste (MSW) may drain into groundwater aquifers as a cons... more Leachate generated from Municipal Solid Waste (MSW) may drain into groundwater aquifers as a consequence of rainfall, transmitted to the conterminous river system through groundwater flow and contaminate the environment. Iraq, because of the lack of accurate data and the high cost of measurement, accurate assessment of leachate generation levels has often been considered a problem. The production of leachate connects into many factors, such as the data of meteorological, levels of waste production, and requirements of design landfill, the large differences in these factors indicate that leachate modelling processes are complicated. The purpose of this paper is to predict the movement of various contaminants in landfill soil in Al Najaf city to predict the behaviour and distribution of landfill pollution in order to properly understand the distribution of contamination in these soil, to control it and to prevent groundwater contamination to predict the depth of leachate from landfill...
This paper is an extension and continuation of an earlier work by the authors on the phenomenon o... more 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, Al-Najaf governorate in Iraq. The authors have developed several power functions 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 non-linear 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 has an R2 of 0.97, while the reach mean depth (Dm) model has an R2 of 0.93. Different statistical methods have been utilized to compare the different models. The results reveal that non-linear regression ...
Kufa Journal of Engineering, 2018
The process of salt dissolution is a reason of structure severe deformation by effective settleme... more The process of salt dissolution is a reason of structure severe deformation by effective settlement. This paper investigates the effect of soaking process on the soil samples from site near the Faculty of Engineering at University of Kufa. Four samples (S1, S2, S3 and S4) were taken from different locations near the selected site. These samples were soaked for two weeks' duration then tested with standard Proctor to estimate the change in the maximum dry density with reference one (natural samples). All samples experience an increase in the maximum dry density and this increase varies from sample to another (1.02, 18.73, 0.1613 and 5.61%) corresponding to the initial conditions of the samples such as water content (2.78, 8.33, 3.733 and 18.4%). The soil is expected, according to this increase in density, to experience an additional settlement upon the soaking, and this settlement increases with increasing the duration of soaking process.
Journal of Engineering and Technological Sciences, 2019
Installing vertical sand drains is a traditional dam foundation consolidation solution that is ec... more Installing vertical sand drains is a traditional dam foundation consolidation solution that is economical and provides good drainage efficiency. Vertical sand drains can shorten the path of water flow inside the soil and speeds up soil consolidation. This study investigated the effect of sand drains in the foundation of the Sombar Dam in Iran on its mechanical behavior. The Sombar Dam is a project to control flooding and provide agricultural water to Gholaman city in northeastern Iran. The investigation included the mechanical behavior of the dam with vertical sand drains. The studied parameters were drain diameter, depth and spacing in addition to the vertical-to-horizontal permeability ratio (ky/kx) of the foundation soil during the time of construction of the dam using a Mohr-Coulomb (MC) model in the software application GeoStudio. The results revealed that reducing the drain spacing (increasing the number of drains) and increasing the depth and diameter of the drains led to an ...
Infiltration Characteristics of Compacted Samples of Sub-Base Materials
Many problems are generated by the presence of water from different sources in a pavement structu... more Many problems are generated by the presence of water from different sources in a pavement structure. The infiltration characteristics of the sub-base 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 changing the soil properties within infiltration. The present work emphasis on the characteristics of the infiltration by using laboratory model. This model is performed on compacted sub-base samples of specific density and different heights, 10, 15, and 20cm, for different heads of water, 10, 15, and 20cm. The results revealed that there is a significant effect of water head and height of sub-base layer on the infiltration with high interaction of the wetting conditions of the sample. A statistical analysis was made to develop a relationship among the different studied parameters.
The demand for water in the developing world, of which the Middle East is a part. In Iraq, the wa... more 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.
Continuity Analysis in Hydraulic Geometry Relationships for Al Abbasia Reach in Euphrates River
International Journal of Scientific and Engineering Research
Most of the hydraulic geometry relationships derived under premises that there are direct or indi... more 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.
International Journal of Scientific and Engineering Research
Most of the hydraulic geometry relationships derived under premises that there are direct or indi... more 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.
Water Infiltration Characteristics of Al Najaf City Soil
Najaf is one of the most important cities in Iraq, lies on the edge of the sedimentary plain of t... more Najaf is one of the most important cities in Iraq, lies on the edge of the sedimentary plain of the lower Mesopotamian. Historically speaking Najaf consists of two cities, the old represents small districts surrounding the holy shrine of Imam Ali and new which extends to the east and southern east. Najaf soil is very complicated, distinguished by the presence of gypsum crystals incorporated with lumps of sands in addition to the presence of holes and/or cavities on the ground surface. This paper focuses on the rate of water infiltration through the base and surrounding walls of a pit with dimensions 8m by 5.5m and 0.4m in depth filled with water. 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.
Water Infiltration Characteristics for Artificial Lake in Bahr Al-Najaf
Al-Najaf is one of the important cities in Iraq due to its high spiritual and religious reputatio... more 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 t...
Foundation systems of some heritage buildings in Najaf/Iraq case study
Geotechnical Engineering for the Preservation of Monuments and Historic Sites, 2013
ABSTRACT The word “Khan” refers to the place where visitors to Najaf city will rest for few days.... more ABSTRACT 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.
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Papers by Mohammed S H A K I R Mahmood
and changing the gypseous soil structure, i.e., increasing the void ratio, and this behavior also depends on the net stress level. With the demolition of the voids under high-stress levels, there is a decrease in water volume change at zero matric suction (saturation). A comparison is made
between the predicted soil water characteristics curve (SWCC) for the soil with the investigated values. The results show a shifting, which may be due to the accuracy of the curve fitting or/and the effect of the loading and gypsum content. This new understanding should help improve
predictions of the impact of the load, gypsum content, and time.