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The conventional remotely-sensed satellite imagery is suited for regionalinvestigations in areas of good exposures which are reduced in southern Iraq due tovegetation, water – covered areas and flat terrains. An imagery produced fromdigitally processed geophysical data is an extremely powerful technique foridentification of geological features in such areas of extreme economic importance .By utilizing an appropriate digital processing, the geophysical contour maps havebeen converted to geophysical images. Images produced from digitally processedgeophysical data (gravity and aeromagnetic) have been analyzed by polynomialfiltering ( using several degrees ) allow major features to be delineated clearly. Anintegrated image of gravity and aeromagnetic data sets has been produced using thebest of polynomial filtering ( 6th degree residuals ) . The interpretation of final outputimages shows the association of negative gravity and magnetic residual anomalieswith some anticlinal structures , while positive residuals are associated with theothers. The positive residuals could be due to basement uplift , and the reversedvalues could be due to deep- seated light core probably salt beds. Basrah depressionexhibits negative residuals.

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Synergistic display of data recorded by different remote sensing has provedextremely valuable for the extraction of geological features such as lineaments .Accordingly , two satellite images were used for lineaments analyses which areconsidered as indicators for rock fractures . Image resolution merge anddirectional filtering methods were applied for lineaments extraction using GIStechniques .Rose diagram and lineaments density analysis were used for the tracedlineaments . The output of these techniques are used to trace new lineaments as aregional lineaments map . a synergistic display of these regional lineaments withgeophysical images allows the major lithological and structural boundaries to bemapped . Evaluation of lineaments map and its rose diagram analyses shows thatthe dominant lineament trend is mainly NW-SE and NE-SW. It is concluded thatthese lineaments indicate the fault zones within the area. Besides, a considerableconformity has been noticed between the location and dimension of suchlineaments with subsurface anomalies appeared in geophysical images

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Soft clays are widely spread in Iraq particularly in its southern Mesopotamian plain. As many sites within these regions may be used for vital projects; an adequate solution has been found out to improve such clays using stone column and dynamic compaction methods. For this purpose, the present paper has presented the laboratory measurements of the properties of such clays and their settlements at different applied stresses. Thirteen soil model tests have been made, at 27% water content and 9 kPa undrained shear strength, to examine theirbehaviors under loading .The tested models include : (1) model for untreated soil ; (3) models for soil treated with stone columns (1,2 and 3 columns) with 30mm in diameter and 180mm length ; (9) models for soil treated with dynamic compaction using drop weights 2 , 3 and 5kg at three different drop heights ( 500 , 750 , and 1000mm ) . For dynamic compaction, the behavior of soil stress - settlementreflects two stages for 2 and 3 kg drop weights with slow and rapid settlements respectively. Whereas , three stages were identified using 5kg drop weight with slow, medium and quick settlements. No considerable effect of drop height and no noticeable improvements have been indicated with soil model treated by dynamic compaction except for weight drop of 5kg but with less improvement ratio compared with stone columns model test. Whereas, the behavior of stresssettlementusing stone columns reflects three stages with slow, rapid and slow(again) settlements . In comparison with untreated soil, the maximum cumulative settlement improvement ratios were 69% and 178% at applied stress of 30 kN/m2 for soil models treated with dynamic compaction ( 5kg drop weight ) and 3 stone columns respectively .

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Ground penetrating radar (GPR) is a geophysical technique of imaging thesubsurface structures at high resolution and it is a non-destructive technique canconsequently be applied in many civil engineering fields and sensitiveenvironments. The amount of data collected however can be very large and takea significant level of subjective experience to interpret. This study focuses uponthe ability of using the GPR with 250 MHz and 500 MHz antennas (intermediatefrequencies) to investigate the reinforced concrete to indicate the quantity ofsteel bars and their configurations in the concrete constructed in the hiddenmensurations. The recent study shows the ability of using the intermediatefrequency antennas for such fields.

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Ground-penetrating radar (GPR) technique was used at University of Technology-Baghdad, as a non destructive, quick, low cost and powerful technique in detecting any change in the constituents of subsurface as materials which can be consequently applied in urban and constructed areas. The main objectives of this study are: to simulate GPR data obtained by 250 and 500 MHz antennas for shallow engineering investigation by detecting different subsurface bodies. A simulation is made for GPR data with different geometric buried bodies and located at different depth. Before processing, most of the raw data of radargram do not reflect the presence of the buried bodies. But after processing by using suitable filters and other interpretation tool parameters, many of the investigated subsurface bodies and structures appeared clearly. It is found from this study that the degree of clarity of the buried bodies do not depend on the higher value of dielectric constant of the body, but it depends on the contrast between the body and the host medium. Thus the body with low dielectric constant appears more clear than that with higher dielectric constant, when they are at the same depth. Most of the buried bodies appeared on GPR radargrams using the medium frequencies. The best detecting depth are 1.5 m to 1 m for 250 and 500 MHz antennas respectively.

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The sandy soil which covers the surface layer for the investigated area consists ofhigh gypsum content (50%). The soil was found to be a “collapsible” soil. Thusbentonite and kaolinite have been used as an improving agents for such soil. Theessential idea of this study represents an investigation of the possibility of usingthese materials as additives with different percents (5%, 10%, 15%, and 20%) toenhance these soils. A testing program was conducted on 9 models of untreated andtreated gypseous soil specimens to study the behavior of such mixes as well as theireffects on physical properties, collapsibility and compressibility characteristics. Itwas concluded that a significant reduction in collapsibility reaching 80 to 82 % forthe 10 percent mixed kaolinite and bentonite respectively. Lowest compressionindex (Cc) and recompression index (Cr) have been obtained using the samepercentages of mixed additives. Generally, best improving results have beenobtained using bentonite additive (specially the ratio 10%) for its finer grains thanthose of kaolinite.

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The piled raft foundations allow an increase in the load capacity and reduction of 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 numerical modeling study was performed considering different factors and conditions. This study highlights the percentage ratio of bearing loads between the pile and the pile cap (raft). Present modeling results obtained by computer program (Plaxis 3D Foundation V 1.1) have been verified with an experimental work of the same problem using the same configuration but extended to include 8 and 16 piles with raft for different soil layers. In addition, a comparison of the present results is achieved with another a theoretical study using the program (Ansys). The finite element method through Plaxis program evaluates the effect of parameter on the load-settlement behavior of the piled raft foundation. The effect of spacing between piles on the load-settlement behavior of the piled raft foundation was also studied. The percentage of the load carried by piles to the total applied load of the numerical model for case sixteen piles with raft is around 42%. The contribution to carry the load of piles relative to the total load is decrease with the increase of the spacing to diameter ratio. The percentage of the load carrying for piled raft for the case of two piles with raft only decreases about 23% when the spacing between piles increases from 3 to 10 times pile diameters.

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The present study investigated the possibility of enhancing collapsible gypseous soil of Al-Qarma site (with relatively high gypsum content around 50%), which is located in Al-Anbar Governorate, using kaolinite and bentonite as additives. The essential idea is concentrated in mixing these additives with natural soil using different percentages (5, 10, 15 and 20% by soil dry weight) to investigate soil shear strength enhancement. The effect of such additives on soil shear strength parameters, cohesion (C) and angle of internal friction (Φ), and their behavior were studied using direct shear test. The results showed that shear strength parameters of soil sometimes increased and then decreased with increasing additives. Generally, higher shear strength parameters have been obtained from bentonite mixed soil than that of kaolinite mixed soil for the same percentages of additives. It was concluded that bentonite was much more effective in increasing C and reducing Φ than kaolinite. While, kaolinite was much more effective in reducing C than bentonite. It was also concluded that gypseous soil shear strength is improved using such additives (with only 5% kaolinite or with only 20% bentonite) which provide cohesion strength to the soil mass and also acts as a binder agent material.

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Electrical Resistivity Imaging (ERI) method is one of the most promisingtechniques which is well suited for the applications in the fields of geohydrology,environmental science and engineering. The present work is aimed to show theefficiency of 2D Electrical Resistivity Imaging (ERI) and Induced Polarization (IP) inprobing the subsurface soil for site investigation and differentiating the clayey soillayers as it is a common practice to measure the IP sounding along with resistivity forcorrect interpretation of field data. The study has demonstrated the practicalapplication of 2D ERI and IP tomography along 7 lines using Wenner- Schlumbergerarray. The data analysis comprises of 2D inversions using the RES2DINV software,thus 2D electrical resistivity and IP imaging sections have been obtained. The depth ofinvestigation was 4 m, and resistivity values range from <1 to 292 ohm.m. Twoelectrical layers were recognized: the upper layer with high resistivity (7-71 ohm.m)represents the loamy soil extends to a depth around 1.3 m; and the second layer withlow resistivity (<1-9 ohm.m) represents the clayey layer. Some anomalous low andhigh electric zones are appeared reflecting the inhomogeneity in deposits. The IPvalues are ranging from -2 to 17 mV/V showing good confirmation with resistivitydata, where high chargeability are associated with low resistivity. The study revealsthat combining IP with resistivity surveys is recommended since IP is, sometimes, veryeffective in relieving ambiguity in interpretation.

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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.

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