The electrical resistivity method is one of the geophysical methods for detecting weak subsurface zone. The 2D resistivity data were used to compare three electrode configurations, Wenner, Dipole-dipole, and Schlumberger, to detect weak subsurface zones along a profile south of Baghdad near the Bismayah pumping station. The results show many zones of low resistivity that may be weak zones. A dipole-dipole array is a large number of measurements and is more sensitive than others. The Wenner-Schlumberger array has a depth also higher than other arrays. Wenner array has higher signal strength than other arrays. Because it is more sensitive to horizontal and vertical structures, the dipole-dipole array is the optimum for mapping subsurface weak zone.
The presence of natural voids and fractures (weak zones) in subsurface gypsiferous soil and gypsum, within the University of Al-Anbar, western Iraq. It causes a harsher problem for civil engineering projects. Electrical resistivity technique is applied as an economic decipher for investigation underground weak zones. The inverse models of the Dipole-dipole and Pole-dipole arrays with aspacing of 2 m and an n-factor of 6 clearly show that the resistivity contrast between the anomalous part of the weak zone and the background. The maximum thickness and shape are well defined from 2D imaging with Dipole-dipole array, the maximum thickness ranges between 9.5 to 11.5 m. It is concluded that the 2D imaging survey is a useful technique and more
... Show MoreSix ERI profiles using Wenner Schlumberger array were carried out at Baghdad University (ALJadiriya campus) to investigate soil at two sites. The spacing between electrodes of four profiles surrounding the new building in the Campus at the first site is 1 m, and the profile length ranges from 50 to 90 m. In comparison, two across profiles in the garden to detect water seepage in the site. The inverted model of the studied profiles shows many high and low resistivity zone. The sedimentology and mineralogy of the soil samples analysis from a depth range of 15 to 100 cm from three pits confirm the high homogeneity of the soil in the studied site composed of (silt and clay). The low resistivity values coincided with the moisture a
... Show MoreThe 2D resistivity imaging technique was applied in an engineering study for the investigation of subsurface weakness zones within University of Anbar, western Iraq. The survey was carried out using Dipole-dipole array with an n-factor of 6 and a-spacing values of 2 m and 5 m. The inverse models of the 2D electrical imaging clearly show the resistivity contrast between the anomalous parts of the weakness zones and the background resistivity distribution. The thickness and shape of the subsurface weakness zones were well defined from the 2D imaging using Dipole-dipole array of 2 m a-spacing. The thickness of the weakness zone ranges between 9.5 m to 11.5 m. Whereas the Dipole-dipole array with a-spacing of 5 m and n-factor of 6 allocated
... Show More2D Electrical Resistivity has been applied at three selecting areas within the study area using Dipole-dipole and Wenner arrays with an a-spacing of 1 m, and the profile length was 120 m for both. The total data points were 4455 reads for Dipole-dipole, and the total data points for Wenner were 2340 reads, and the depth of each array was 15.4 m and 20.2 m, respectively. The 2D inverse results indicate the resistivity anomalies approximately at depth (2 - 7.8) m formed as a weakness zone lies within the quaternary and Injana Formation deposits and interbedded with secondary gypsum and gypcretes. Additionally, the inverse resistivity distribution model demonstrated that the area is impacted by groundwater that is interaction wit
... Show MoreCracking of soils affects their geotechnical properties and behavior such as soil strength and stability. In this paper, 2D Electrical Resistivity Imaging Method, as a non-invasive technique, was adopted to investigate the effect of soil cracks of a centemetric scale on resistivity of sandy soil. The electrical resistivity measurements were carried out using ABEM SAS 300C Terrameter system at a laboratory scale using Wenner array. The measurements were interpreted using horizontal profiles, forward modeling and 2D inverse resistivity sections. The results showed that soil cracks cause significant changes in soil resistivity. These changes can be attributed to the high resistivity contrast between the highly resistive air-filled cracks an
... Show MoreThe current study aims to identify soil pollutants from heavy metals The study utilized 40 topsoil (5 cm) samples, which adapted and divided into seven regions lies in Baghdad governorate, included (Al-Husainya,(Hs) Al-Doura (Do), Sharie Al-Matar (SM), Al-Waziria (Wz), Nharawan (Nh), Abu Ghraib (Abu) and Al-Mahmoodyia (Mh)). Spatial distribution maps of Nickel (Ni), Manganese (Mn), Lead (Pb) and Zinc (Zn) were created for Baghdad city using Geographic Information Systems (GIS). The concentrations of four heavy metals in the soil of different area of Baghdad were measured and observed using XRF instrument. The result found highest values of Pb and Zn at the middle of the Baghdad in (Wz
Iraq is located near the northern tip of the Arabian plate, which is advancing northwards relative to the Eurasian plate, and is predictably, a tectonically active country. Seismic activity in Iraq increased significantly during the last decade. So structural and geotechnical engineers have been giving increasing attention to the design of buildings for earthquake resistance. Dynamic properties play a vital role in the design of structures subjected to seismic load. The main objective of this study is to prepare a data base for the dynamic properties of different soils in seismic active zones in Iraq using the results of cross hole and down hole tests. From the data base collected it has been observed that the average ve
... Show MoreA land magnetic survey was carried out along regional profile, which is located at the north part of the Iraqi western desert. It starts from al –Qaam City (at north) toward Rutba City (at south) with a total length of 238km. The survey was carried out along the paved road between the two cities, About 113 measuring points were done with inter-station distance of 2 km (for 198 km) and 2 to 5km (for 40km). Two proton magnetometers were used in this survey. One of them is used for base station monitoring, which was fixed as of Salah Aldin field (Akkas). Its readings were used for diurnal corrections. All magnetic measurements were corrected for normal and topographic corrections. The readings were reduced to a certain base level. The resu
... Show MoreIraqi western desert is characterized by a widespread karst phenomenon and caves. Euphrates formation (Lower Miocene) includes enormous sinkholes and cavities within carbonate rocks that usually cause severe damages to any kind of engineering facilities built over it. 3D resistivity imaging techniques were used in detecting this kind of cavities in complicated lithology. The 3D view was fulfilled by collating seven 2D imaging lines. The 2D imaging survey was carried out by Dipole-dipole array with (n) factor and electrode spacing (a) of 6 and 2m respectively. The horizontal slices of the 3D models give a good subsurface picture. There are many caves in all directions (x, y, z). They reveal many small caves near the surface. Thes
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