scholarly journals Preliminary Assessment of the Soil Foundation Characteristics Utilizing the 2D Resistivity Imaging and Down-Hole Seismic Refraction Techniques: A Case Study in Tenth of Ramadan City, Egypt

2021 ◽  
pp. 3587-3600
Author(s):  
Shokry A. Soliman ◽  
Salah Shebl ◽  
Ahmed El Khafif ◽  
T.F. S Hazley ◽  
M.H. Farag
Keyword(s):  
Electrical Resistivity ◽  
Elastic Moduli ◽  
Seismic Refraction ◽  
Industrial Area ◽  
Coarse Sand ◽  
High Resistivity ◽  
S Waves ◽  
Resistivity Imaging ◽  
Geotechnical Characteristics ◽  
2D Resistivity

      Two-dimensional electrical resistivity imaging and seismic refraction, in the form of down-hole survey, were applied to delineate the subsurface section and elastic moduli and identify geotechnical characteristics of subsurface materials in the 10th of Ramadan industrial area, Cairo, Egypt. The results of four 2-D profiles of electrical resistivity, in the form of dipole–dipole and Wenner configurations, revealed that the subsurface section contains two main geo-electrical layers; the first is made of sand, some silt, and gravels, reflecting low resistivity values ranging from 25 to 65.5 ohm m. This layer is overlying a high resistivity layer (65.5 to135 ohm m), corresponding to medium to coarse sand, with gravel and calcareous materials. It is worth noting that that the down-hole technique was used to measure velocities of P and S waves in order to derive the low strain dynamic elastic properties, such as Poisson’s ratio, Shear modulus, stress ratio, concentration index, N-value, and the ultimate and allowable bearing capacities of the subsurface soil, down to an approximate depth of 30 m in the borehole at the site. In addition, the Vs30 value was calculated and revealed that the soil is categorized as a NEHRP class (D). Furthermore, the results of geotechnical parameters and elastic moduli were found to be realistic and sensible for the purposes of engineering constructions and imply that the soil in the study area is characterized by fairly to moderately competent quality. A new empirical correlation is proposed between the obtained Vs and resistivity values, where Vs = 1.0302 ρ + 172.74.

scholarly journals Evaluation and Delineation of Sulfur Groundwater Leakages Using Electrical Resistivity Techniques in Hit Area, Western Iraq

2021 ◽  
pp. 2239-2249
Author(s):  
Osama J. Mohammed ◽  
Ali M. Abed ◽  
Mohammed A. Alnuaimi
Keyword(s):  
Electrical Resistivity ◽  
Imaging Technique ◽  
Polluted Water ◽  
High Resistivity ◽  
Resistivity Imaging ◽  
Groundwater Movement ◽  
2D Resistivity Imaging ◽  
Array Position ◽  
Two Stages ◽  
2D Resistivity

      Electrical resistivity methods are one of the powerful methods for the detection and evaluation of shallower geophysical properties. This method was carried out at Hit area, western Iraq, in two stages; the first stage involved the use of 1Dimensional Vertical Electrical Sounding (VES) technique in three stations using Schlumberger array with maximum current electrodes of 50m. The second stage included the employment of two dimension (2D) resistivity imaging technique using dipole-dipole array with a-spacing of 4m and n-factor of 6 in two stations. The 1D survey showed good results in delineating contaminated and clear zones that have high resistivity contrast. Near the main contaminated spring, the 2D resistivity imaging technique was applied in four sections length (100 m) using a dipole-dipole array position coincided with the three points VES. We compared the results of the interpretation of imaging the techniques 2D and VES. We found that the 2D imaging resistivity technique was better than VES survey in determining the distribution of pollution under the surface in the area surveyed. It was also found that the polluted water is located about 5 m below the surface. The largest amount of leakage was found towards the northeast and coincided with the direction of the groundwater movement. Spring water has leaked from outside the region through the Kubaisah area. Most of this water is contained in quaternary deposits and karst gypsum fractures.

scholarly journals Electrical resistivity tomography applied to geologic, hydrogeologic, and engineering investigations at a former waste-disposal site

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. B231-B239 ◽  
Author(s):  
Jonathan E. Chambers ◽  
Oliver Kuras ◽  
Philip I. Meldrum ◽  
Richard D. Ogilvy ◽  
Jonathan Hollands
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Site Investigation ◽  
High Resistivity ◽  
Potential Zone ◽  
Resistivity Tomography ◽  
L2 Norm ◽  
Resistivity Model ◽  
2D And 3D ◽  
2D Resistivity

A former dolerite quarry and landfill site was investigated using 2D and 3D electrical resistivity tomography (ERT), with the aims of determining buried quarry geometry, mapping bedrock contamination arising from the landfill, and characterizing site geology. Resistivity data were collected from a network of intersecting survey lines using a Wenner-based array configuration. Inversion of the data was carried out using 2D and 3D regularized least-squares optimization methods with robust (L1-norm) model constraints. For this site, where high resistivity contrasts were present, robust model constraints produced a more accurate recovery of subsurface structures when compared to the use of smooth (L2-norm) constraints. Integrated 3D spatial analysis of the ERT and conventional site investigation data proved in this case a highly effective means of characterizing the landfill and its environs. The 3D resistivity model was successfully used to confirm the position of the landfill boundaries, which appeared as electrically well-defined features that corresponded extremely closely to both historic maps and intrusive site investigation data. A potential zone of leachate migration from the landfill was identified from the electrical models; the location of this zone was consistent with the predicted direction of groundwater flow across the site. Unquarried areas of a dolerite sill were imaged as a resistive sheet-like feature, while the fault zone appeared in the 2D resistivity model as a dipping structure defined by contrasting bedrock resistivities.

scholarly journals Geophysical Delineation of Barite-Galena Mineralization Using Coupled Electrical Resistivity (ER) and Induced Polarization (IP) Techniques. A Case Study of Iyamitet, Cross River State, South-South, Nigeria

2021 ◽  
pp. 11-18
Author(s):  
O. J. Airen ◽  
D. A. Babaiwa
Keyword(s):  
Electrical Resistivity ◽  
Joint Inversion ◽  
Induced Polarization ◽  
High Resistivity ◽  
Cross River ◽  
Cross River State ◽  
Geophysical Techniques ◽  
Mineralized Zone ◽  
2D Resistivity

A combined Electrical Resistivity (ER) and Induced Polarization (IP) techniques were carried out at Iyamitet, Cross-River State Nigeria with the aim of mapping the Barite-Galena mineralization zone within the area. Five traverses were established in orthogonal directions with length of 100 m. The traverses were established in grid format for better coverage of the study area and Dipole-Dipole electrode configuration was adopted for the data acquisition for both ER and IP. Res2Dinvx software was employed for the joint inversion of the data and the resulting 2D resistivity and chargeability images of the subsurface were interpreted qualitatively and semi-quantitatively to locate the mineralized zone. The result of the investigation revealed that the resistivity values of the suspected mineralized zones fall between 1023 ohm-m to 377599 ohm-m and the chargeability falls between 232 msec and 727 msec. The depth to the top of some of the mineralized zones is as shallow as 1.25 m and as deep as 19.8 m in other places. The results of the investigation have indicated the presence of the Barite-Galena ore within the area and this manifested as high resistivity and high chargeability zones along the traverses. The result of this investigation highlights the efficiency of combined geophysical techniques in locating mineralized zones in a basement area.

scholarly journals Time-lapse electrical resistivity investigation of seawater intrusion in coastal aquifer of Ibeno, Southeastern Nigeria

2020 ◽  
Vol 10 (11) ◽  
Author(s):  
Iniemem J. Inim ◽  
Ndifreke I. Udosen ◽  
Moshood N. Tijani ◽  
Uduak E. Affiah ◽  
Nyakno J. George
Keyword(s):  
Electrical Resistivity ◽  
Coastal Aquifer ◽  
Saltwater Intrusion ◽  
Time Lapse ◽  
Electrode Spacing ◽  
High Resistivity ◽  
Southeastern Nigeria ◽  
Salinity Changes ◽  
Survey Length ◽  
2D Resistivity

Abstract Saltwater intrusion, erosion, and periodic flooding during severe storms are some of the critical problems bedeviling the precarious coastal environment of Nigeria. A time-lapse study aimed at monitoring the dynamics of saltwater intrusion within the coastland surrounding Ibeno, southeastern Nigeria is presented. Three (3) vertical electrical soundings (VES) and four time-lapse electrical resistivity tomography (ERT) profiles with minimum and maximum electrode spacing of 5 m and 40 m and profile lengths of 120 m and 150 m respectively were acquired in 2016 and 2017 using the Wenner and Schlumberger arrays. Data acquired from the field surveys were modeled with WINRESIST and RES2DINV software to generate 1D and 2D resistivity images of the subsurface. The VES results with a maximum survey length of AB = 300 m revealed a four-layer KH curve. The 2D geo-electrical sections delineated contrast between the high resistivity values obtained for the saturated freshwater zones and the low resistivity values obtained for the saturated saltwater zone. Expectedly, the intrusion was dominant nearer the coastline than inland. The salinity changes are believed to have been caused by both incremental tides passing through highly porous materials in the active-salinity change area and over-pumping of groundwater. The time-lapse resistivity measurements showed significant, active lateral salinity changes rapidly intruding the freshwater aquifers. The study demonstrates the application of time-lapse 2D ERT and vertical electrical sounding in identifying the spatial and temporal changes of saltwater intrusion in the coastal aquifer.

scholarly journals 2-D Electrical Resistivity Imaging Survey for Lithological Assessment at Igwete Primary School, Amai, South-South Nigeria

2021 ◽  
Vol 25 (5) ◽  
pp. 823-827
Author(s):  
V.C. Enebeli ◽  
C.N. Okorafor ◽  
R.E. Kolagbodi
Keyword(s):  
Electrical Resistivity ◽  
Primary School ◽  
Electrode Array ◽  
Lateral Position ◽  
Electrical Resistivity Imaging ◽  
Clayey Sand ◽  
Near Surface ◽  
Resistivity Imaging ◽  
Lateral Extent ◽  
2D Resistivity

Electrical Resistivity Imaging (ERI) is a useful near-surface imaging technique, which mainly include data acquisition, numerical modelling and tomographic inversion. Within the study area, only one – dimensional (1-D) Electrical Resistivity survey has been carried out for Geophysical investigations. Therefore, 2-D ERI survey was carried out at the Igwete Primary School, Amai to provide electrical picture of the subsurface from which discrete bodies and lithology are better revealed vertically and in lateral extent. The 2-D ERT survey data were acquired using the Petrozenith Earth Resistivity meter while employing the Wenner electrode array. The 2-D apparent resistivity data were inverted to obtain true resistivities of the subsurface using res2dinv software running on personal computer. The subsurface resistivity models were displayed as pseudo sections and inverted resistivity section in the form of colour shaded contour maps. The inverse resistivity model images indicate that at a lateral extent in the range (15.00-21.00) m and (33.00-39.00) m, anomalies suspected to be gravel mixed with sand is in place with resistivities of about (254.00-948.00) Ωm. From the geologic section we can infer that a geological formation is observed at a lateral position of (27.00-32.00) m of resistivity in the range (90.00-93.00) Ωm. This structure is inferred to be a clay pocket. The sandy nature of the formation requires that underground water development be sought for at (9.00-15.00) m over a depth (2.30-8.00) m in the sandy environment. Results of 2D resistivity imaging has helped to delineate the lithology which comprise mainly of; sand, sandy clay, clayey sand depositional environment. The resistivity of these lithology falls in the range (90.00-93.00) Ωm with depth to formation of about (2.30-6.00) m.

Two‐ and three‐dimensional electrical resistivity imaging at a heterogeneous remediation site

Geophysics ◽  
2004 ◽  
Vol 69 (3) ◽  
pp. 674-680 ◽  
Author(s):  
Laurence R. Bentley ◽  
Mehran Gharibi
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Electrical Resistivity Imaging ◽  
Resistivity Imaging ◽  
Out Of Plane ◽  
Conductivity Anomalies ◽  
Forward And Inverse Modeling ◽  
2D Resistivity ◽  
Improve Cost ◽  
Sour Gas

Geometrically complex heterogeneities at a decommissioned sour gas plant could not be adequately characterized with drilling and 2D electrical resistivity surveys alone. In addition, 2D electrical resistivity imaging profiles produced misleading images as a result of out‐of‐plane resistivity anomalies and violation of the 2D assumption. Accurate amplitude and positioning of electrical conductivity anomalies associated with the subsurface geochemical distribution were required to effectively analyze remediation alternatives. Forward and inverse modeling and field examples demonstrated that 3D resistivity images were needed to properly reconstruct the amplitude and geometry of the complex resistivity anomalies. Problematic 3D artifacts in 2D images led to poor inversion fits and spurious conductivity values in the images at depths close to the horizontal offset of the off‐line anomaly. Three‐dimensional surveys were conducted with orthogonal sets of Wenner and dipole–dipole 2D resistivity survey lines. The 3D inversions were used to locate source zones and zones of elevated ammonium. Thus, conducting 3D electrical resistivity imaging (ERI) surveys early in the site characterization process will improve cost effectiveness at many remediation sites.

scholarly journals Geo-electrical assessment of coefficient of permeability and porosity of leachate plume at Asin dumpsite, Iwaro-oka, southwestern Nigeria

2016 ◽  
Vol 63 (2) ◽  
pp. 97-108
Author(s):  
Cyril Okpoli ◽  
Michael Oladunjoye ◽  
Toluwaleke Ajayi
Keyword(s):  
Electrical Resistivity ◽  
Crystalline Basement ◽  
Two Dimensional ◽  
Southwestern Nigeria ◽  
High Coefficient ◽  
Resistivity Imaging ◽  
Coefficient Of Permeability ◽  
Average Porosity ◽  
Leachate Plume ◽  
2D Resistivity

Abstract An integrated geophysical (involving two-dimensional [2D] electrical resistivity) and petrophysical study was conducted in the Precambrian Crystalline Basement area of Iwaro-oka Akoko, southwestern Nigeria. Five 2D resistivity profiles, both around the perimeters and inside the dump, were investigated with maximum lengths of 100 m. Results of the resistivity imaging delineated the leachate plumes as low-resistivity zones, with values ranging from 3 Ω m to 55 Ω m. The coefficient of permeability ranged from 4.33 × 10-6 to 7.82 × 10-3, and the average porosity ranged from 32 Ω m to 169 Ω m, thus indicating migration of leachate plume to the groundwater due to the high coefficient of permeability and the porosity.

scholarly journals Simulation of geoelectrical responses of structures buried in freshwater and brackish water environments

2021 ◽  
Vol 27 (1) ◽  
pp. 69-83
Author(s):  
Opeyemi Joshua Akinrinade ◽  
Tolulope Emmanuel Oginni ◽  
Elnalee Buyagao Baguya
Keyword(s):  
Brackish Water ◽  
Optimization Technique ◽  
Coarse Sand ◽  
Static Model ◽  
Least Square ◽  
Water Model ◽  
High Resistivity ◽  
Water Medium ◽  
Buried Structures ◽  
2D Resistivity

Marine geoelectrical simulation offers the opportunity to predict matrix type, interstitial fluid and geometry of buried structures. In this research, simulation of geoelectrical responses over buried structures in freshwater and brackish water environments were tested. A model tank made of acrylic and housed within an iron frame was built for the experiment. The tank was filled with water and sieved sediment having grain sizes ≤1.18 mm, corresponding to very coarse sand to colloid. Four models were designed namely freshwater static model (FSM), brackish water static model (BSM), freshwater model with buried structures (FMBS), and brackish water model with buried structures (BMBS). A bamboo pipe, metal pipe and granite block were buried in the FMBS and BMBS. Physico-chemical parameters of the water which includes temperature (22.74 – 26.06 °C), salinity (0.07 – 15.72 psu), conductivity (153 – 25,420 μS/cm  and resistivity (5.6 x 103 – 6.6 x 103 Ω-cm) were measured. Dipole-dipole array using inter-electrode separation (a) of 5 cm and 1≤n≤5 was adopted. Resistivity measurements obtained were processed and inverted using non-linear least-square optimization technique. We present obtained results as contoured 2D resistivity structures. FSM and FMBS were characterized by relatively high resistivity values compared with the BSM and BMBS. The buried  materials were effectively resolved in the freshwater models, compared to the brackish water model due to higher contrast in resistivity between the material and saturating fluid. The bamboo pipe was not effectively delineated in the brackish water medium, as a result of the low resistivity contrast which exists between the medium and the material. Zones with high compaction are characterized by high resistivity values, while concealed channel structures were characterized by low compaction. Estimated depth were exact for the freshwater models but was over estimated by `∼12.5% in the brackish water models. Marine electrical resistivity method shows great potential in mapping structures buried in medium with high contrasting resistivity values, and sedimentary structures with varying degree ofcompaction.

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