Geoelectrical Characterization of the Al-Kawamil New Settlement, Sohag, Egypt

2019 ◽  
Vol 24 (2) ◽  
pp. 327-332
Author(s):  
Mohammed A. Mohammed ◽  
Abdelbaset M. Abudeif
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Site Investigation ◽  
University Campus ◽  
Clayey Sand ◽  
Near Surface ◽  
Drilling Site ◽  
The University

Electrical resistivity tomography (ERT) is one of the most effective geophysical methods used to acquire detailed pictures of subsurface conditions without drilling. Site investigation using two- and three-dimensional electrical resistivity imaging is now a fundamental step before the design and construction of campus buildings at the University of Sohag in Egypt. In this study, an ERT survey was implemented at two pre-defined sites with the aim of selecting the most favorable location for construction of a new educational building on the university campus. The resistivity results were confirmed with boreholes drilled at both sites. RES2DINV and RES3DINV software were used for data processing and interpretation. The results show that the near surface sedimentary succession beneath both sites consists of four geoelectrical and lithological units. From the surface to a depth of 20 m, these layers are: unit 1) unconsolidated boulders and gravels intercalated with percentages of sand and reddish clay; unit 2) fine crushed calcareous gravels and sands with clays intercalations; unit 3) dry sand and clayey sand; and unit 4) shale, at the base. According to an evaluation of the presence and abundance of shale and sand contents cracks, fissures and faults, the second site is identified as more suitable for construction.

Multi-methodological investigation of a retrogressive thaw slump in the Richardson Mountains, Northwest Territories, Canada

2020 ◽  
Author(s):  
Julius Kunz ◽  
Christof Kneisel ◽  
Tobias Ullmann ◽  
Roland Baumhauer
Keyword(s):  
Electrical Resistivity ◽  
Active Layer ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Active Layer Thickness ◽  
Permafrost Degradation ◽  
Low Resistivity ◽  
Permafrost Table ◽  
Retrogressive Thaw Slump ◽  
Richardson Mountains

<p>The Mackenzie-Delta Region is known for strong morphological activity in context of global warming and permafrost degradation, which reveals in a large number of retrogressive thaw slumps. These are frequently found along the shorelines of inland lakes and the coast; however, this geomorphological phenomenon also occurs at inland ​​streams and creeks of the Peel Plateau and the Richardson Mountains, located in the southwest of the delta. Here several active retrogressive thaw slumps are found of which some have reached an extent of several hectares, e.g. the mega slump at the Dempster Creek.</p><p>In this study we investigated a recent retrogressive thaw slump at the edge of the Richardson Mountains close to the Dempster Highway to determine the subsurface properties using non-invasive geophysical methods. We performed three-dimensional Ground Penetrating Radar (GPR) surveys, as well as quasi-three-dimensional Electrical Resistivity Tomography (ERT) surveys in order to investigate the subsurface characteristics adjacent to the retreating headwall of the slump. These measurements provide information on the topography of the permafrost table, ice content and/or water pathways on top, within or under the permafrost layer. Additionally, we performed manual measurements of the active layer thickness for validation of the geophysical models. The approach was complemented by the analysis of high-resolution photogrammetric digital elevation models (DEM) that were generated using in situ drone acquisitions.</p><p>The measured active layer depths show a strong influence of the relief and especially of small creeks on the permafrost table topography. Likely, this influence also is the primary trigger for the initial slump activity. In addition, the ERT measurements show strong variations of the electrical resistivity values in the upper few meters, which are indicative for heterogeneities, also within the ice-rich permafrost body. Especially noticeable is a layer of low resistivity values in an area adjacent to the slump headwall. This layer is found at depths between 4m to 7m, which approximately corresponds to the base of the headwall. Here, the low resistivity values could be indicative for an unfrozen or water-rich layer below the ice-rich permafrost. Consequently, this layer may have contributed to the initial formation of the slump and is important for the spatial extension of the slump.</p><p>These results present new insights into the subsurface of an area adjacent to an active retrogressive thaw slump and may contribute to a better understanding of slump development.</p>

scholarly journals Integrated Study of Geotechnical and Geophysical Methods to Assess the Soil Corrosion Potential for Construction Site

2020 ◽  
Vol 11 (3) ◽  
pp. 79-85
Author(s):  
Perveiz Khalid ◽  
Shahzada Khurram ◽  
Zia Ud Din ◽  
Syed Atif Ali ◽  
Alabjah Bahija
Keyword(s):  
Electrical Resistivity ◽  
Corrosion Potential ◽  
Geophysical Methods ◽  
Steel Structures ◽  
Critical Issue ◽  
Silty Clay ◽  
Soil System ◽  
Near Surface ◽  
Soil Corrosion ◽  
Electrical Resistivity Survey

Corrosion of subsurface steel structures is very critical issue especially in moisture subsoil. The use ofphysiochemical properties such as pH, salts concentration, electrical resistivity is very common to quantify corrosivenature of subsoil. However, the laboratory measurements of these parameters are quite difficult due to time and budgetconstraints. In this work soil corrosion potential of a power plant site was evaluated using geophysical and geotechnicalinvestigations. Soil samples were collected from 15 boreholes drilled up-to 50 m depth for laboratory testing whereas 3probes of four electrodes vertical electrical sounding (VES) using Wenner configuration were also performed tomeasure the electrical resistivity of the subsurface soil up to 50 m depth. According to the USCS soil system silty clay(CL-ML) was interpreted as dominant material in all boreholes as shallow depth. Poorly graded sand (SP) including silt(SM) was found of variable depth in almost each borehole. The true resistivity values at the depth of 30 meters liesbetween the 19.9 ohm- meters to 59.8 ohm meters. All observation points of electrical resistivity survey VES-I, VES-IIand VES-III near-surface material show moderate soil corrosion potential which is favorable for design of earthing. Upto depth of 4 m, the values of resistivity 52.6 to 59.8 ohm-meters shows adequate estimation of corrosion. According tothe International standard these curves belong to bell type or K type curve of resistivity model. Their resistivity valueswith respect to depth show low to moderate corrosion potential which is satisfactory for construction at this depth afterapplying the nominal cathodic protections. Thus, electric pipe lines may be installed at this depth.

scholarly journals Subsurface Investigation Using Electrical Resistivity Imaging for Proposed Industrial Site near Erbil-Kirkuk Borders, Northern Iraq

2021 ◽  
Vol 54 (2E) ◽  
pp. 198-209
Author(s):  
Osamah Al-Saadi
Keyword(s):  
Electrical Resistivity ◽  
Geophysical Methods ◽  
Electrode Spacing ◽  
Electrical Resistivity Imaging ◽  
Industrial Site ◽  
Near Surface ◽  
Running Water ◽  
Resistivity Imaging ◽  
Clastic Rocks ◽  
Industry Area

The friendly-environment geophysical methods are commonly used in various engineering and near-surface environmental investigations. Electrical Resistivity Imaging technique was used to investigate the subsurface rocks, sediments properties of a proposed industrial site to characterize the lateral and vertical lithological changes. via the electrical resistivity, to give an overview about the karst, weak and robust subsoil zones. Nineteen 2D ERI profiles using Wenner array with 2 m electrode spacing have been applied to investigate the specific industry area. One of these profiles has been conducted with one-meter electrode spacing. The surveyed profiles are divided into a number of blocks, each block consists of several parallel profiles in a specific direction. The positions of Electrical Resistivity Imaging profiles in the project area have been determined according to a preliminary subject plan from the civil engineers for factory foundation constructions and proposed locations of heavy machines. The inversion results of profiles showed that areas of blocks A, B, C, and D consist mainly of clastic rocks and sediments, e.g., claystone, siltstone and sandstone. The Electrical Resistivity Imaging inversion sections of blocks A, B, C, and D do not show any indication of cavitation or weak zones of sizes more than 2.0 meters, and no signs of gypsum bodies are found in these areas in general. Gypsum bodies are probably detected at block E, the southern part of the study area. The researchers recommended to keep these rocks in block E away from the continuous running water to avoid cavitation. Furthermore, the construction of heavy machines should keep away from this part of the study area to avoid to some extent, subsoil failure and subsidence in the future. Middle and Northern parts are more consistent to the constructions and factory foundations.

TIME-LAPSE ELECTRICAL RESISTIVITY CHARACTERIZATION OF LNALP POLLUTION IN A CLAYEY-SAND FORMATION

2006 ◽  
Author(s):  
Adekunle. A. Adepelumi ◽  
Adetutu. A. Solanke ◽  
Oluwatobi. B. Sanusi ◽  
Helen. O. Ogundipe
Keyword(s):  
Electrical Resistivity ◽  
Time Lapse ◽  
Clayey Sand

scholarly journals Detection of Cover Collapse Doline and Other Epikarst Features by Multiple Geophysical Techniques, Case Study of Tarimba Cave, Brazil

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2835
Author(s):  
Yawar Hussain ◽  
Rogerio Uagoda ◽  
Welitom Borges ◽  
Renato Prado ◽  
Omar Hamza ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Least Square ◽  
P Wave ◽  
Positive Anomaly ◽  
Refraction Tomography ◽  
Collapse Doline

Reliable characterization of the karst system is essential for risk assessment where many associated hazards (e.g., cover-collapse dolines and groundwater pollution) can affect natural and built environments, threatening public safety. The use of multiple geophysical approaches may offer an improved way to investigate such cover-collapse sinkholes and aid in geohazard risk assessments. In this paper, covered karst, which has two types of shallow caves (vadose and fluvial) located in Tarimba (Goias, Brazil), was investigated using various geophysical methods to evaluate their efficiency in the delineation of the geometry of sediments filled sinkhole. The methods used for the investigation were Electrical Resistivity Tomography (ERT), Seismic Refraction Survey (SRS), Seismic Refraction Tomography (SRT) and the Very Low Frequency Electromagnetic (VLF-EM) method. The study developed several (2D) sections of the measured physical properties, including P-wave velocity and electrical resistivity, as well as the induced current (because of local bodies). For the analysis and processing of the data obtained from these methods, the following approaches were adopted: ERT inversion using a least-square scheme, Karous-Hjelt filter for VLF-EM data and time-distance curves and Vp cross-sections for the SRS. The refraction data analysis showed three-layered stratigraphy topsoil, claystone and carbonate bedrock, respectively. The findings obtained from ERT (three-layered stratigraphy and sediment-filled doline), as well as VLF-EM (fractured or filled caves as a positive anomaly), were found to be consistent with the actual field conditions. However, the SRS and SRT methods did not show the collapsed material and reached the limited the depth because of shorter profile lengths. The study provides a reasonable basis for the development of an integrated geophysical approach for site characterization of karst systems, particularly the perched tank and collapse doline.

Détermination de la géométrie et des propriétés physiques du pergélisol discontinu de la région de Schefferville

1977 ◽  
Vol 14 (3) ◽  
pp. 431-443 ◽  
Author(s):  
Maurice K.-Seguin
Keyword(s):  
Electrical Resistivity ◽  
Regional Scale ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Near Surface ◽  
Vertical Extension ◽  
Discontinuous Permafrost ◽  
Propriétés Physiques ◽  
Lower Limits

The various parameters used to predict on a regional scale the lateral and vertical extension of permafrost are the following: surface temperature, thermal conductivity of rocks, and geothermal flow configuration. Locally this type of data is generally not sufficient and far too inaccurate. The use of geophysical methods at the surface and in boreholes in addition to existing thermal data helps to improve the degree of accuracy in the prediction of spatial distribution of permafrost in a given area. These geophysical methods include seismic refraction, electrical resistivity, and spontaneous and induced polarizations.Because of the properties of permafrost, seismic refraction at surface is useful only to determine the top of the permafrost whereas electrical resistivity (electric logging near surface) allows the determination of the upper and lower limits of permafrost. Seismic refraction, resistivity, and spontaneous and induced polarizations in boreholes were deemed more promising to determine masses or lenses of permafrost.Moreover, it was possible to correlate temperature and electrical resistivity measurements in boreholes, thus allowing the drawing of isothermal curves from electric logging in areas of continuous and discontinuous permafrost, at least when it is 'marginal'.The data for this study were obtained from the experimental station at Schefferville, Québec. [Journal Translation]

Tire Contact Stresses and Their Effects on Instability Rutting of Asphalt Mixture Pavements: Three-Dimensional Finite Element Analysis

2003 ◽  
Vol 1853 (1) ◽  
pp. 150-156 ◽  
Author(s):  
Marc Novak ◽  
Bjorn Birgisson ◽  
Reynaldo Roque
Keyword(s):  
Asphalt Mixture ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Shear Stresses ◽  
Element Analysis ◽  
Surface Shear ◽  
Near Surface ◽  
Vertical Loading ◽  
Stress States

Instability rutting generally occurs within the top 2 in. of the asphalt layer when the structural properties of the asphalt concrete are inadequate to resist the stresses imposed on it. Several researchers have presented observations in attempts to explain instability rutting, but a clear identification of the mechanism does not exist. Stresses in the asphalt layer caused by measured tire interface stresses were analyzed in three dimensions by using finite elements to identify possible mechanisms for instability rutting. The analysis showed that radial tires produce high near-surface shear stresses at low confinements, which are not predicted with traditional uniform vertical loading conditions, in the region where instability rutting is known to occur. The resulting shear stresses tend to be shallower than for the uniformly loaded case, and they are focused in areas where instability rutting has been observed. The observed stress states imply that the characterization of instability rutting requires testing at these low confinement (and sometimes tensile) stress states, rather than at the higher stress states typically used in the strength characterization of mixtures.

scholarly journals IMAGING TREE ROOT ZONE GEOMETRY USING ELECTRICAL RESISTIVITY TOMOGRAPHY

2020 ◽  
Vol 30 (1) ◽  
pp. 55
Author(s):  
Asep Mulyono ◽  
Ilham Arisbaya ◽  
Yayat Sudrajat
Keyword(s):  
Electrical Resistivity ◽  
Cross Sections ◽  
Electrical Resistivity Tomography ◽  
Root Zone ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
Soil Surface ◽  
Resistivity Tomography ◽  
Root Plate ◽  
Maesopsis Eminii

Root zone geometry research is usually done in a conventional way which is destructive, time-consuming, and requires a considerable cost. Several non-destructive measurements used geophysical methods have been developed, one of which is the Electrical Resistivity Tomography (ERT) method. Tree root zone determination using ERT has been carried out in Kiara Payung area, Sumedang, West Java, with Maesopsis eminii tree as the object study. A total of 29 ERT lines were measured using dipoledipole configuration with electrodes spacing of 50 cm. The results of two-dimensional (2D) and three-dimensional (3D) inversion modeling show that the ERT method has been successfully imaging the tree root zone. The root zone is characterized as 100-700 Ωm with an elliptical shape geometry of the root plate. The root radius is estimated to be 4-5 m from the stem, the root zone diameter reaches 8-9 m at the shallow soil surface and the root zone depth is approximately 2-2.5 m. ABSTRAK Pencitraan geometri zona perakaran pohon menggunakan electrical resistivity tomography. Penelitian geometri zona perakaran biasa dilakukan dengan cara konvensional yang destruktif, memakan waktu, dan membutuhkan biaya yang tidak sedikit. Beberapa pengukuran non-destruktif menggunakan metode geofisika telah dikembangkan, salah satunya adalah metode Electrical Resistivity Tomography (ERT). Penentuan zona perakaran pohon menggunakan metode ERT telah dilakukan di daerah Kiara Payung, Sumedang, Jawa Barat, dengan pohon Maesopsis eminii sebagai objek studi. Sebanyak 29 lintasan ERT diukur menggunakan konfigurasi dipole-dipole pada dengan jarak antar elektroda 50 cm. Hasil pemodelan inversi dua dimensi (2D) dan tiga dimensi (3D) menunjukkan bahwa metode ERT telah berhasil mencitrakan zona perakaran pohon. Zona perakaran teridentifikasi berada pada nilai resistivitas 100-700 Ωm dengan root plate dan root cross-sections berbentuk elips. Radius akar diperkirakan sejauh 4-5 m dari pangkal batang, sedangkan diameter zona perakaran mencapai sekitar 8-9 m di permukaan tanah dangkal dan kedalaman zona perakaran diperkirakan antara ~2-2.5 m. 

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