Application of the Electrical Resistivity Method for Site Investigation in University of Anbar, Ar-Ramadi City, Western Iraq

The 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 the geoelectrical stratigraphic layers sequence in low-accuracy of weakness zones, but deeper than the inverse model of 2 m a-spacing. This survey was made to explain the correlation between the weakness zone and the deeper layers in the study area. It points out that the deeper layers were not affected in the weakness zones. The inverse model was produced using the Standard Least-Squares Inversion Method and the Robust Inversion Model Constraints Method. The first method had a gradational boundary of the weakness zones and the second had sharper and straighter boundaries of fractures and voids within the weakness zones.

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An Investigation of Groundwater Contamination around Nsukka Municipality Dumpsite using the Resistivity Method

10.14293/s2199-1006.1.sor-.pp22t3k.v1 ◽

2020 ◽

Author(s):

Olisah Nzemeka

Keyword(s):

Electrical Resistivity ◽

Groundwater Contamination ◽

Low Resistivity ◽

Electrical Resistivity Survey ◽

Resistivity Method ◽

Electrical Sounding ◽

On Line ◽

2D Resistivity Imaging ◽

Resistivity Meter ◽

2D Resistivity

An investigation using electrical resistivity method was conducted around a solid waste dumpsite at Nsukka in Nsukka L.G.A of Enugu State, Nigeria to investigate the level of groundwater contamination. Electrical Sounding (VES) and 2D resistivity imaging were used with a digital read out resistivity meter (ABEM SAS 1000) to acquire data in the area. A total of eight (8) sounding and six (6) 2D resistivity imagings were carried out in the area. A contaminant leachate plume was delineated in 2D resistivity sections as low resistivity zones while the VES shows the depth of aquifer. In 2D pseudosections where bluish colours with low resistivities (less than 20.80Ωm) with the depth ranging from 1.28m to 17.1m in the Line 1 and 2 are seen as contaminated zones. The rest of the lines are not contaminated because of their high resistivities (greater than 20.80Ωm). The result of the electrical resistivity survey also showed 4 - 5 layers geo-electric sections and an AA and AK type sounding curves. The VES result shows that VES 1A, 1B, 2A and 2B which are carried out on line 1 & 2 of the wenner lines showed signs of contamination with low resistivity values less than 20.80Ωm complementing the wenner results. The contamination has not yet got to where the aquifer is located on the lines. Since the depth to the aquifer ranges from 30.26m to 155.43m while maximum depth of contamination is 17.1m. It is believed that the leachate has not percolated down to the aquiferous zones as such aquifers are presumed to be free.

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Site Investigation Using 2D Resistivity Imaging to Detect Subsurface Cavities and Weak Zones at Mosul’s Stadium, North Iraq (A Case Study)

Second International Conference on Engineering Geophysics ◽

10.3997/2214-4609.20131871 ◽

2013 ◽

Author(s):

N.H. Al-Saigh

Keyword(s):

Site Investigation ◽

Resistivity Imaging ◽

North Iraq ◽

2D Resistivity Imaging ◽

2D Resistivity ◽

Subsurface Cavities ◽

Weak Zones

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Uncertainties Analysis of Electrical Resistivity Tomography

10.5194/egusphere-egu21-340 ◽

2021 ◽

Author(s):

Yonatan Garkebo Doyoro ◽

Chang Ping-Yu ◽

Jordi Mahardika Puntu

Keyword(s):

Model Resolution ◽

Resistivity Data ◽

Resistivity Method ◽

Resistivity Model ◽

2D Resistivity Imaging ◽

Model Set ◽

Different Depths ◽

Measured Resistivity ◽

2D Resistivity ◽

Subsurface Cavities

<p>We examined the uncertainty of the resistivity method in cavity studies using a synthetic cavity model set at six-different depths. Conceptual models were simulated to generate synthetic resistivity data for dipole-dipole, pole-dipole, Wenner-Schlumberger, and pole-pole arrays. The 2D geoelectric models were recovered from the inversion of the synthetically measured resistivity data. The highest anomaly effect (1.46) and variance (24400) in resistivity data were recovered by dipole-dipole array, while the pole-pole array obtained the lowest anomaly effect (0.60) and variance (2401) for the target cavity T<sub>1</sub>. The anomaly effect and variance were linearly associated with the quality of the inverted models. The steeper anomaly gradient of resistivity indicated more distinct cavity boundaries, while the gentler gradient prevents the inference of the cavity boundaries. The recovered model zone above the depth of investigation index of 0.1 has shown relatively higher sensitivity. Modeling for dipole-dipole array provided the highest model resolution and anomaly gradient that shows a relatively distinct geometry of the cavity anomalies. On the contrary, the pole-dipole and Wenner-Schlumberger arrays recovered good model resolutions and moderate anomaly gradient but determining the anomaly geometries is relatively challenging. Whereas, the pole-pole array depicted the lowest model resolution and anomaly gradient with less clear geometry of the cavity anomalies. At deeper depths, the inverted models showed a reduction in model resolutions, overestimation in anomaly sizes, and deviation in anomaly positions, which can create ambiguity in resistivity model interpretations. Despite these uncertainties, our modeling specified that the 2D resistivity imaging is a potential technique to study subsurface cavities.</p>

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Assessment of Subsurface Profile at SILC, Nusajaya by 2D Resistivity Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.695.823 ◽

2014 ◽

Vol 695 ◽

pp. 823-827

Author(s):

Siti Norsalkini Mohd Akip Tan ◽

Edy Tonnizam Mohamad ◽

Rosli Saad ◽

Mustaza M. Nordiana

Keyword(s):

Electrode Spacing ◽

High Resistivity ◽

Iron Mineral ◽

Resistivity Method ◽

Survey Line ◽

2D Resistivity Imaging ◽

Actual Profile ◽

Grade Ii ◽

Physical And Chemical ◽

2D Resistivity

An assessment of subsurface profile of a study area at Nusajaya. Johor was conducted using 2D resistivity method. The aims of the study are to determine the subsurface profile hence contouring the appearance of outcrop by 2D resistivity imaging. Subsurface structure can be delineated based on the physical and chemical parameter which is apparent resistivity of the medium. A survey line of 80m and minimum 2m electrode spacing was adopted using Pole-dipole array. Data acquisition on the survey line was completed and processed by using Res2Dinv software. The inversion model resistivity shows sandstone contains iron mineral (30-250 ohm-m) and weathered sandstone (500-1000 ohm-m). The lower part of the layer represents sandstone and siltstone exhibit high resistivity values of 1500-5000 ohm-m. The range from 30-1000 ohm-m correspond to the grade IV and V of sandstone in the actual profile. Meanwhile, the high range of the resistivity value matched the material with weathering grade II and III in ground mass. The deterioration of most physical properties was associated with the increase number of weathering grade.

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Detection of the near surface structure through a multidisciplinary geophysical approach

Open Geosciences ◽

10.2478/s13533-011-0034-2 ◽

2011 ◽

Vol 3 (4) ◽

Author(s):

Eleni Kokinou ◽

Apostolos Sarris

Keyword(s):

Seismic Refraction ◽

Geophysical Methods ◽

Near Surface ◽

The Road ◽

Resistivity Method ◽

Conductivity Anomalies ◽

2D Resistivity Imaging ◽

Limestone Rock ◽

Ground Penetrating ◽

2D Resistivity

AbstractThe present survey aimed to image the subsurface structure, including karstic voids, and to evaluate the extent of the heterogeneities that can result in potentially dangerous collapse of road segments overlying these features. A multidisciplinary geophysical approach (seismic refraction, frequency domain electromagnetic and ground penetrating radar) in combination with a detailed geological survey indicated the presence of tectonic faults as well as velocity and conductivity anomalies along an old road within the area of Akrotiri at Chania (Crete). Due to the presence of subsurface fuel pipes, perpendicular to the direction of the road, 2D resistivity imaging was excluded from the applied geophysical methods.Interpretation of the geophysical data revealed that the section of the road investigated overlies prominent voids attributed mostly to karst features. The conductivity and velocity anomalies are interpreted to indicate an area where the host limestone rock has been downthrown by faulting and associated karstification. The continuation of this fault zone was observed in the slope of the road during later excavations. Interpretation, using geographic information systems (GIS) to integrate data, allowed these controls and relationships to be understood and monitored. The above methodology was proved successful for areas where the application of resistivity method is not possible.

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Application of Electrical Resistivity Method to Site Characterisation for Construction Purposes at Institute of Agriculture Research and Training Moor Plantation Ibadan

Indonesian Journal of Earth Sciences ◽

10.52562/injoes.v1i2.248 ◽

2021 ◽

Vol 1 (2) ◽

pp. 49-62

Author(s):

Babatunde A. Adebo ◽

Oladipupo Emmanuel Makinde ◽

Stephen Olubusola Ilugbo

Keyword(s):

Electrical Resistivity ◽

Clay Content ◽

Site Investigation ◽

Geophysical Investigation ◽

Weak Zone ◽

Southwestern Nigeria ◽

Entire Study ◽

Resistivity Method ◽

Electrical Imaging ◽

And Training

This research was carried out within Institute of Agriculture Research and Training Moor Plantation Ibadan, Southwestern Nigeria, with the aim to ascertain suitability of the proposed site for building construction and usage. The geophysical investigation involved three electrical resistivity techniques; Vertical Electrical Sounding (VES) using the Schlumberger configuration, 2D ERT and 2-D electrical imaging using Dipole-dipole electrode configuration. Two traverses were established E–W direction cutting across geologic strike with a distance of 80 m and of varying inter-traverse spacing. Eight (8) VES stations were occupied covering the entire study area for layer stratification and geoelectric parameters. The results were qualitatively and quantitatively interpreted and are presented as sounding curves and geoelectric sections. The 2-D imaging gave information on the subsurface characteristic in the area with generally low apparent resistivity indicating low competence material. The results obtained from the VES delineate three geoelectric units which comprise of the topsoil, weathered layer and fresh basement. The results from the VES were used to determine the second order parameters. The entire results correlate well with one another showing that all the techniques used were complemented. This study has further justified the need for geophysical site investigation as pre-condition before any construction to avoid problems of differential settlement. In determining of foundation material, topography elevation, clay content and the depth of weak zones should be put into consideration, since the depth of the weak zone is appreciably high.

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