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1

The use of non-invasive ERT method to diagnose karst in road engineering in the Lublin Upland (Poland)

Maślakowski Maciej, Lejzerowicz Anna, Pacanowski Grzegorz, Kuszyk Rafał

Archives of Civil Engineering

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2024

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Vol. 70, nr 1

557--571

EN

Appropriate design in linear construction depends on many factors, including detailed geological conditions. One of the biggest problems are unrecognized erosion forms, in particular karst ones, which have a huge impact on the design and subsequent operation of roads. For this purpose, in addition to conventional methods such as drilling or geotechnical probing, which are point-based, non-invasive spatial geophysical methods are used. This article presents an example of the use of geoelectrical surveys, Electrical Resistivity Tomography (ERT) for the recognition of karst zones for linear investments. The article describes ERT investigations, which to some extent allows to identify dangerous karst phenomena occurring in the Lublin Upland (Poland), which are of great importance at the design stage of roads and in their further safe operation. Non-invasive geophysical research has been verified and confirmed by traditional geotechnical research, which confirms the effectiveness of their use. The Electrical Resistivity Tomography was used as a method providing a broader spectrum of knowledge on the spatial arrangement of soil layers in the subgrade of the planned road investments. It also enabled a more accurate, more detailed interpretation of geotechnical studies. The described geophysical investigations opens wide possibilities for their application to researchers. In the future, non-invasive methods have a chance to become as reliable as geotechnical methods, but this requires a lot of research to improve the effectiveness and accuracy of the interpretation of the obtained results.

PL

Odpowiednie projektowanie w budownictwie liniowym zależy od wielu czynników, w tym szczegółowo rozpoznanych warunków geologicznych. Jednym z największych problemów stanowią nierozpoznane formy erozyjne w szczególności krasowe mające ogromny wpływ na projektowanie i późniejszą eksploatację dróg. W tym celu poza metodami konwencjonalnymi takimi jak wiercenia czy sondowania geotechniczne które s ą punktowe, wykorzystuje się metody geofizyczne przestrzenne – nieinwazyjne. W niniejszym artykule przedstawiono przykład zastosowania badan geoelektrycznych dla rozpoznania stref krasu dla projektów liniowych. Metody geofizyczne od lat cieszą się dużą popularnością w trakcie rozpoznawania warunków gruntowo-wodnych. Mimo, iż w dalszym ciągu uchodzą za metody nowatorskie to już na stałe zostały wpisane jako obowiązkowe podczas rozpoznawania warunków geologicznych czy geotechnicznych. Są oczywiście weryfikowane przez szczegółowe badania geotechniczne, nie mniej jako badania uważane za przestrzenne pozwalają na szersze spojrzenie pod powierzchnię terenu i wyłapania ewentualnych zagrożeń do których należą różnego rodzaju zagłębienia erozyjne wypełnione słabonośnymi gruntami czy nawet pustki powstałe na skutek procesów krasowych. Do najdokładniejszych metod geofizycznych należy tomografia elektrooporowa (Electrical Resistivity Tomography, ERT) wykorzystująca zjawisko różnego przewodnictwa prądu elektrycznego gruntu w zależności od jego składu i struktury. W artykule zostały opisane badania ERT pozwalające w pewnym stopniu rozpoznać niebezpieczne zjawiska krasowe zachodzące na Wyżynie Lubelskiej, które mają bardzo duże znaczenie na etapie projektowania dróg oraz w ich dalszej bezpiecznej eksploatacji. Nieinwazyjne badania geofizyczne zostały zweryfikowane i potwierdzone tradycyjnymi badaniami geotechnicznymi co potwierdza skuteczność ich stosowania. Przedstawiona metoda tomografii elektrooporowej (ERT) została wykorzystywana jako metoda dająca szersze spektrum wiedzy na temat przestrzennego ułożenia warstw gruntowych w podłożu projektowanych inwestycji drogowych. Umożliwiła również dokładniejszą, bardziej szczegółową interpretację ę badan geotechnicznych. Dzięki metodzie ERT ułatwione zostało wskazanie strefy możliwego występowania krasu lub rozcięć erozyjnych – w skałach węglanowych, możliwych pustek krasowych lub rozcięć wypełnionych osadami czwartorzędowymi, głównie w postaci piaszczystych lub gliniastych zwietrzelin. Na ich podstawie wytypowano obszary trwających procesów geodynamicznych, które zakwalifikowano do skomplikowanych warunków gruntowych. Przedstawiona interpretacja wyników badan ERT niestety w dalszym ciągu nie jest jednoznaczna i wymaga potwierdzenia badaniami szczegółowymi za pomocą inwazyjnych badan geologicznych, takich jak wiercenia lub sondowania. Poza rozpoznaniem w miarę dokładnych granic poszczególnych wydzieleń nie otrzymano żadnych informacji szczegółowych, takich jak dokładny skład gruntu czy tez jego stan, stąd tez wskazanie miejsc występowania realnych dysfunkcji nie było proste. Opisane badania geofizyczne otwierają przed badaczami szerokie możliwości ich zastosowania. W przyszłości metody nieinwazyjne mają szansę stać się równie wiarygodne jak metody geotechniczne, lecz wymaga to przeprowadzenia wielu badań poprawiających skuteczność i trafność interpretacji uzyskiwanych wyników.

2

Surface damage assessment by analysis of electrical resistance changes in graphite-based sensing skin

Stepnowski Marek, Janczak Daniel, Jakubowska Małgorzata, Pyrzanowski Paweł

Metrology and Measurement Systems

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2022

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Vol. 29, nr 2

347--360

EN

The article presents the method of identifying surface damage by measuring changes in resistance in graphite-based sensing skin. The research focused on analysis of conductivity anomalies caused by surface damage. Sensitivity maps obtained with Finite Element Method (FEM) in conjunction with the analytical damage model were used to build the coating evaluation algorithm. The experiment confirmed the ability of this method to identify a single elliptical-shape damage. Eight electrodes were enough to locate the damage that covered about 0.1‰ of the examined area. The proposed algorithm can prove useful in simple applications for surface condition monitoring. It can be implemented wherever it is possible to apply a thin layer of conductor to a non-conductive surface.

3

An integrated approach for landslide hazard assessment: A case study of the Middle Dnieper Basin, Ukraine

Ivanik Olena, Fonseca Joana, Shabatura Oleksandr, Khomenko Ruslan, Hadiatska Kateryna, Kravchenko Dmytro

Journal of Water and Land Development

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2022

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no. 52

81--86

EN

Ukraine is characterised by active natural hazards processes within different structural, tectonic and landscape zones. In Middle Dnieper basin region mass movement processes have great impact on people’s livelihoods and infrastructure. These processes occur on the slopes with different geological structure. The determining causes include lithologic and stratigraphic conditions, hydrogeological regime, structural and textural peculiarities of rocks and the geomorphology of the slopes. Landslide inventory database has been developed based on long-term observations of more than 400 landslides and landslide-prone areas. This paper takes efforts forward by combining different geological and geophysical methods to advance the current understanding of landslide phenomena and contributing towards a better informed assessment of landslide hazard and risk. The developed methodology is implemented in a test sites of Kyiv region, covering an area of 18.3 km2 situated in the Middle Dnieper basin. Electrical Resistivity Tomography, Self-Potential and Infrared Thermography techniques were employed to investigate the lithostratigraphic sequences, the geometry of landslide body and potential mass movement. The results presented here confirm the potential of using an integrated approach that combines different field data to better plan mitigation activities and measures for the effective land management. This study will be useful in increasing the safety aspects of the infrastructures and lives and also for planning of research and developmental activities.

4

Subsurface imaging of fluvial deposits of the Wisła River valley in Kraków (southern Poland) by 2D ERT survey

Bania Grzegorz, Woźniak Tomasz

Geological Quarterly

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2022

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Vol. 66, No. 3

art. no. 23

EN

We describe the application of 2D ERT (electrical resistivity tomography) surveys to investigate the spatial complexity of fluvial deposits of the Wisła River valley in the eastern part of Kraków (southern Poland). All ERT survey lines were completed within the industrially influenced floodplain of the Wisła River at two research sites. Due to the transformation of the natural state of the environment through many years of industrial activity of the ArcelorMittal Kraków plant, some of the geomorphological elements analysed have been irretrievably transformed and hidden by anthropogenic accumulations such as waste landfills and engineering structures. Hence, many years of soil contamination have changed the primary resistivity characteristics of the subsurface. For this purpose, the measurement array applied combines standard arrays, i.e., Wenner-Schlumberger and Dipole-Dipole, which gave improved results (higher resolution) in comparison to the standard single array. The data interpretation method was supported by the calculation and visualization of the vertical and horizontal gradients of the interpreted resistivity within the resistivity sections. This approach allowed accurate determination of resistivity boundaries on the ERT resistivity sections and thus helped lithological interpretation of the fluvial deposits in the research area. The resistivity of water in a channel located within one of the analysed areas has impacted some of the research results. Furthermore, 2D ERT forward modeling was implemented to generate synthetic datasets. The synthetic data allowed investigation of the influence of groundwater contamination on the resistivity distribution within superficial layers, and also tested the ability of the 2D ERT model to recognize the detailed spatial distribution of palaeomeander (meander scar) infills. All methods have provided new information on the industrially influenced floodplain of the Wisła River in Kraków.

5

3D subsoil reconstruction of a mud volcano in central Sicily by means of geophysical surveys

Grassi Sabrina, De Guidi Giorgio, Patti Graziano, Brighenti Fabio, Carnemolla Francesco, Imposa Sebastiano

Acta Geophysica

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2022

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Vol. 70, no 3

1083--1102

EN

The upwelling of fluids, subject to overpressure, along with discontinuities in the subsoil, causes the formation of geological structures known as mud volcanoes. These structures, very widespread in the world and in some cases located near inhabited centers, can represent a considerable risk factor for the population, as they can give rise to paroxysmal eruptions, even very violent. The assessment of the characteristics and structure of the subsoil of the areas affected by this phenomenon can prove to be a useful tool for risk mitigation. Non-invasive geophysical surveys were carried out in the area of the active cone of the Santa Barbara mud volcano in order to obtain a 3D characterization of the subsoil. Through the processing and integration of data derived from active and passive seismic surveys was obtained, a 3D model showing the seismostratigraphic subsoil structure. The electrical resistivity tomography surveys provided results comparable to those obtained from seismic surveys and supplied information on the perimetral areas of the mud volcano. The information obtained is useful to study the boundary conditions that influence short-scale activity. Furthermore, this study seeks to evaluate the possibility of using the proposed methodological approach for monitoring the variations that occur over time in the areas affected by mud volcanoes phenomenon.

6

Electrical resistivity tomography for geo-engineering investigation of subsurface defects: a case study of Etioro-Akoko highway, Ondo State, southwestern Nigeria

Akingboye Adedibu Sunny, Osazuwa Isaac Babatunde, Mohammed Muraina Zaid

Studia Quaternaria

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2020

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Vol. 37, Nr 2

101--107

EN

The durability of roads is dependent on the proper screening of the variations in subsurface geological characteristics and conditions through geo-engineering investigations and good construction practices. In this study, electrical resistivity tomography (ERT) technique was used to investigate the subsurface defects and potential failures along the substrate of Etioro-Akoko highway, Ondo State, southwestern Nigeria. Results of the inverse model resistivity sections generated for the two investigated traverses showed four distinct subsurface layers. The shallow clayey topsoil, weathered layer, and partially weathered/fractured bedrock have resistivity values ranging from 4–150 ohm-m, 10–325 ohm-m, and 205–800 ohm-m, with thickness values of 0–2 m, 0.5–12.5 m, and less than few meters to > 24 m, respectively. The fresh bedrock is characterised by resistivity generally in excess of 1000 ohm-m. The bedrock mirrored gently to rapidly oscillating bedrock troughs and relatively inclined deep penetrating multiple fractures: F1–F'1, F2–F'2 and F3–F'3, with floater in-between the first two fractures. These delineated subsurface characteristic features were envisaged as potential threats to the pavement of the highway. Pavement failures in the area could be attributed to the incompetent clayey sub-base/substrate materials and the imposed stresses on the low load-bearing fractured bedrock and deep weathered troughs by heavy traffics. Anticipatory construction designs that included the use of competent sub-base materials and bridges for the failed segments and fractured zones along the highway, respectively, were recommended.

7

Application of the ERT to recognise the geological structure of frost‑riven cliffs localised in the Skalny Potok (Hrubý Jeseník Mts.)

Stan-Kłeczek Iwona, Stan Dominika

Acta Geophysica

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2019

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Vol. 67, no. 6

1759--1764

EN

In the area of the Skalni Potok Nature Reserve (Hrubý Jesenik), studies of gneissic cliffs were carried out to determine the role of lithology in the process of their formation. The research included geometric measurements of vertical discontinuity zones of selected rock outcrops and the electrical resistivity tomography (ERT) measurements of strongly weathered subsurface layers. As a result of the measurement, the orientation of the main crack systems (NW–SE and NE–SW) responsible for the location of cliffs within the Skalni Potok Valley was obtained. In addition, the main crack directions for the gneiss occurring in the studied mountain region were identified. Interpretation of the ERT models allowed to characterise the structure of the rock mass, including the reach of the rainwater infiltration level and the depth of the weathering front.

8

Application of GPR and ERT methods for recognizing of gypsum deposits in urban areas

Gołębiowski Tomisław, Jarosińska Elżbieta

Acta Geophysica

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2019

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Vol. 67, no. 6

2015--2030

EN

This paper presents the selected results of GPR (ground penetrating radar) and ERT (electrical resistivity tomography) surveys carried out on the sites in Poland where shallow karst forms were found in gypsum deposits. The aim of the surveys was the noninvasive detection of karst forms as well as weathered and fractured bedrock which may threaten the stability of the surface and, consequently, may cause damage to buildings, as well as overground and underground infrastructure. The geophysical surveys were conducted at a depth of only a few meters, i.e., to the depth of buildings foundations. GPR surveys were carried out in short-offset reflection profiling mode with standard orientation of the antennae set; however, on one site, different orientations of antennae were tested. During ERT surveys, different measurement arrays were applied in order to analyze which array was optimal for the detection of karst forms as well as weathered and fractured bedrock. Complex interpretation of geophysical surveys resulted in reduced ambiguity and revealed some regions, dangerous for surface stability. Due to the fact that gypsum deposits were investigated to the depth of maximum 10 m; therefore, hydrological processes were analyzed in the paper instead of hydrogeological processes.

9

Role of geophysical surveys in the identification of water escape zones from retention lakes: a case study on a selected object in Upper Silesia

Mieszkowski R., Wójcik E., Kozłowski M., Popielski P.

Studia Quaternaria

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2018

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Vol. 35, Nr 2

121--129

EN

The main scientific goal of this work is the presentation of the role of selected geophysical methods (Ground-Penetrating Radar GPR and Electrical Resistivity Tomography ERT) to identify water escape zones from retention reservoirs. The paper proposes a methodology of geophysical investigations for the identification of water escape zones from a retention fresh water lake (low mineralised water). The study was performed in a lake reservoir in Upper Silesia. Since a number of years the administrators of the lake have observed a decreasing water level, a phenomenon that is not related to the exploitation of the object. The analysed retention lake has a maximal depth between 6 and 10 m, depending on the season. It is located on Triassic carbonate rocks of the Muschelkalk facies. Geophysical surveys included measurements on the water surface using ground penetration radar (GPR) and electrical resistivity tomography (ERT) methods. The measurements were performed from watercrafts made of non-metal materials. The prospection reached a depth of about 1 to 5 m below the reservoir bottom. Due to large difficulties of conducting investigations in the lake, a fragment with an area of about 5,300 m2, where service activities and sealing works were already commenced, was selected for the geophysical survey. The scope of this work was: (1) field geophysical research (Ground-Penetrating Radar GPR and Electrical Resistivity Tomography ERT with geodesic service), (2) processing of the obtained geophysical research results, (3) modelling of GPR and ERT anomalies on a fractured water reservoir bottom, and (4) interpretation of the obtained results based on the modelled geophysical anomalies. The geophysical surveys allowed for distinguishing a zone with anomalous physical parameters in the area of the analysed part of the retention lake. ERT surveys have shown that the water escape zone from the reservoir was characterised by significantly decreased electrical resistivities. Diffraction hyperboles and a zone of wave attenuation were observed on the GPR images in the lake bottom within the water escape zone indicating cracks in the bottom of the water reservoir. The proposed methodology of geophysical surveys seems effective in solving untypical issues such as measurements on the water surface.

10

Electrical resistivity tomography (ERT) and sedimentological analysis applied to investigation of Upper Jurassic limestones from the Krzeszowice Graben (Kraków Upland, southern Poland)

Woźniak T., Bania G., Mościcki W. J., Ćwiklik M.

Geological Quarterly

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2018

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Vol. 62, No. 2

287--302

EN

This paper highlights the application of shallow non-invasive geophysics (electrical resistivity tomography) supported by sedimentological analysis applied to the investigation, description and interpretation of Upper Jurassic limestones exposed in the abandoned quarry near the village of Tomaszowice (Kraków Upland, southern Poland). Within this site, on the northern margin of the Krzeszowice Graben, a facies diversity of Upper Jurassic limestones can be observed. Field exposures were analysed to broadly characterize these Upper Jurassic limestones in terms of facies and microfacies development. Three facies types, including pelitic limestones, bedded limestones and carbonate gravity-flow deposits, composed of numerous microfacies, have been distinguished. ERT study using a dipole-dipole array has been carried out, along 5 parallel 110 m long profiles and along a perpendicular 110 m long profile, north of the Tomaszowice Quarry wall. The use of ERT in combination with the geological data allowed characterization and description of the geology at the research site as well as the determination of the lithological composition and internal architecture of the subsurface. Furthermore, the ERT interpretation results indicated the presence of a series of a secondary faults closely linked with the Krzeszowice Graben. The distribution of the gravity-flow deposits reflects the fault zone pattern of the graben and Late Jurassic fault activity.

11

Case study of electrical resistivity tomography measurements used in landslides investigation, Southern Poland

Mita M., Glazer M., Kaczmarzyk R., Dąbrowski M., Mita K.

Contemporary Trends in Geoscience

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2018

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Vol. 7, iss. 1

110--126

EN

Mass movements are an ever present threat to building construction, water management, vegetation formation and biodiversity. This paper presents an approach to landslides research based on non-invasive geoelectrical method - Electrical Resistivity Tomography (ERT). Mapping and displacement monitoring of unstable slopes is crucial for the hazards prevention and assessment. The ERT technique is an effective tool to obtain structural differentiation of geological medium through interpretation of 2D electrical resistivity models. The main advantage of the method is a wide range of applicability what makes its useful during field works on a landslide. It is commonly used for measurements of slope instability, determination of shear surface, landslide susceptibility, depth of bedrock, slip plane geometry. The aim of the work is to identify the geological structures underneath three selected landslides in south Poland: in Racibórz, Milówka and Porąbka. Attempts have been focused on determination of the usefulness of the proposed ERT methodology for evaluation of possible further development of mass movements. On two investigation sites two different arrays have been used: Wenner-Schlumberger and dipole-dipole which allowed to prepare combined data set and resistivity models based on them. Forward modelling of synthetic models based on a priori information allowed to understand anomalies present on resistivity models. Applied approach ensured quality increase of final interpretation of resistivity models.

12

Compiling and verifying 3D models of 2D induced polarization and resistivity data by geostatistical methods

Mostafaei K., Ramazi H.

Acta Geophysica

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2018

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Vol. 66, no. 5

959--971

EN

A 3D model of collected time-domain induced polarization (IP) and electrical resistivity tomography (ERT) data is compiled by geostatistical methods as well as studying spatial correlation among the database. Mesgaran copper deposit, located in Birjand eastern Iran, was chosen to compile and verify the model, leading to five parallel surveyed IP and ERT profiles with dipole–dipole arrays. The collected data were inverted, and then 2D models of IP and ER were prepared; also 3D inversion was done. Afterward, the 3D model has been built by geostatistical methods. Correspondingly, the anomalies threshold was detected by fractal methods and the estimation variance and Kriging efficiency were calculated to validate the modeling. The mineralization zones were determined according to the classified anomalies and those with the lowest error. Results indicated a high correlation between anomalies identified from the model and mineralization. The results made it possible to construct 3D models from surveyed 2D data with acceptable error level.

13

An attempt to integration of different geophysical methods (magnetic, GPR and ERT); a case study from the late Roman settlement on the Island of Rab in Croatia

Welc F., Mieszkowski R., Lipovac-Vrkljan G., Konestra A.

Studia Quaternaria

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2017

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Vol. 34, Nr 1

47--59

EN

In 2016 within the RED Project Roman Economy in Dalmatia: production, distribution and demand in the light of pottery workshops, 5 selected areas around the Podšilo Bay were geophysically surveyed. During the fieldworks in the Lopar protected area, located in the northeastern part of the Island of Rab a gradiometer, ground-penetrating radar (GPR) and electrical resistivity tomography (ERT) were used. The main aim of the project was to document presence of the Roman architecture in two areas of the bay’s hinterland as suggested earlier by finds of pottery and glass. Geophysical studies conducted in the Lopar area revealed presence of underground remains of ancient structures, probably from the late Roman period and connected with a ceramic production centre at the present seashore. The most interesting results were obtained for the area no. 4, the site where magnetic, georadar and ERT surveys revealed an ancient regular building at 0.4–0.6 m depth. The survey performed in the Lopar area clearly indicates that integration of different geophysical methods enables detailed and effective identification of buried archaeological structures.

14

Zastosowanie badań konduktometrycznych z użyciem inwersji 1D, jako narzędzia do kartowania przestrzennego przypowierzchniowych warstw geologicznych

Czarniak P., Pacanowski G., Sobótka P.

Przegląd Geologiczny

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2017

|

Vol. 65, nr 10/2

803--810

EN

This article presents the results obtained from geophysical measurements as a supplement to and refinement of geological information obtained from engineering geological studies for the newly constructed highways. The research was conducted using two geophysical methods: Ground Conductivity Meters (GCM) and Electrical Resistivity Tomography (ERT). The above measurements were made on three research fields located along the planned express road S-19 (Kraśnik-Janów Lubelski section). These areas were selected due to the large amount of available archival data and varied geological conditions. The publication focuses primarily on the presentation of the results obtained using the very fast and extremely efficient GCM method. By processing GCM data, using Laterally Constrained Inversion (LCI) and Spatially Constrained Inversion (SCI) algorithms, the values ofelectrical resistivity of the surveyed centers were derived. The results are presented in the form of cross-sections and maps of electrical resistivity from different depths, which were collated and compared with the results from another geophysical method, ERT. These examples show that the use of inversion has a significant impact on the refinement of geological boundaries between layers of different electrical resistivities. Thanks to the correlation of geophysical data with boreholes and engineering geological probes, detailed models of the geological structure of the analyzed areas were elaborated, which are necessary for the selection of appropriate solutions for the construction and modernization of road infrastructure.

15

Ocena możliwości zastosowania metody georadarowej i elektrooporowej do identyfikacji rozluźnionych stref gruntów niespoistych

Mieszkowski R., Zawrzykraj P., Żmudzin D., Wójcik E., Popielski P.

Przegląd Geologiczny

|

2017

|

Vol. 65, nr 10/2

779--784

EN

The results of the possibility of geophysical methods application (such as geoelectrical ones, including ground penetrating radar and electrical resistivity tomography) to identify areas of loose sands were presented in the article. Registered anomalies obtained from geophysical survey have been verified by geological and engineering tests (drillings and dynamic probing). Measurements were carried out along the part of the lateral earth dam, consisting of man-made soils with a thickness of approximately 7 m and underlying alluvial medium grained sands. The results obtained from the geophysical survey and direct assessment of density by means of dynamic probing allowed to demonstrate the relationship between a specific type of geophysical anomalies and the density of non-cohesive man-made soils.

16

ERT i GPR – geofizyczne metody badań podłoża wykorzystywane w budownictwie liniowym

Maślakowski M., Józefiak K., Brzeziński K., Superczyńska M.

Przegląd Geologiczny

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2017

|

Vol. 65, nr 10/2

765--771

EN

Correct determination of subgrade layers and properties is fundamental for later design and construction stages. Results obtained using traditional geotechnical tests are always of an overly specific nature - information is only provided in certain points in the field. Number of test points and the accuracy of results’ interpretation among them influence the design of an engineering structure foundation, which greatly impacts the cost of a project. Also, the lack of soil testing or insufficient investigation of soil conditions can be the reason for all kinds of legal claims from contractors which often exceed the whole investment budget by several or even several dozen percent. In order to prevent that situation new directives for geotechnical testing include additional geophysical methods such as electrical resistivity tomography (ERT) and ground penetrating radar (GPR). These non-invasive methods can give a spatial image and thus improve the accuracy of soil strata identification. However, these methods have also disadvantages and inaccuracies related to the measurement principles and interpretation of the results. This paper presents limitations and possible errors of geophysical methods ERT and GPR based on example tests carried out for road and railway engineering structures.

17

Geophysical, geotechnical, and speleologic assessment for karst-sinkhole collapse genesis in Cheria plateau (NE Algeria)

Mouici R., Baali F., Hadji R., Boubaya D., Audra P., Fehdi C., Didier C., Stéphane J., Bruno A.

Mining Science

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2017

|

Vol. 24

59--71

EN

Several sinkhole collapses were occurred in the many sites in urban areas and/or their rural periphery; in NE Algeria, in the last few years. The abrupt collapse causes damages to properties, infrastructures, and even lives. The most spectacular one occurred in February 2009 inside the Cheria city, Northwest of Tebessa department, with a diameter of more than a hundred meters. This abrupt collapse is due to a sudden rupture of the roof of a large underground karst cavity. It caused panic-stricken among the population living near the crater. In order to investigate the origin of this phenomenon, we combine several geophysical and geotechnical methods, such as Ground Penetrating Radar, Electrical Resistivity Tomography, Standard Penetration Test, Mechanical Drill Core, Cave Survey Photogrammetry, etc. It appears that each method may provide specific information. Their comparison allows to precise the results itself, the limits and the application field of each. Consequently a number of open karst voids and disturbed areas were detected in the study area. The results show that sinkholes originate from two different processes: a brutal collapse of karst voids located at shallow depth, by agravitational effect especially building surcharge on top of limestone. And progressive piping and erosion of the thick gravel cover, especially after storms making large depressions. The drawdown of the aquifer following intense pumping could have accelerated these processes. The extension plans of the study area could be established with this methodical acquaintance of the underground conditions of the karst cavities such as: occurrence, depth, geometry and dimensions.

18

Zastosowanie metody elektrooporowej do rozpoznania złóż surowców skalnych

Frycz M., Jeleń M.

Kruszywa : produkcja - transport - zastosowanie

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2017

|

Nr 2

86--93

PL

Metody geofizyczne, ze szczególnym uwzględnieniem tomografii elektrooporowej, w ostatnich latach zyskują coraz większe znaczenie. Jest to efektem ciągłego postępu technologicznego, jaki dokonuje się w dziedzinie aparatur pomiarowych. Artykuł został poświęcony wykorzystaniu metody elektrooporowej w badaniu złóż – zarówno w fazie ich eksploatacji, jak i poszukiwań.

EN

Geophysical methods, with special regard to electrical resistivity imaging, have gained increasing significance in recent years. It is the result of continuous improvement in the field of measuring equipment. The article addresses electrical resistivity method application in deposit exploration, both at the stage of their location and mining. The employment of modern and advanced equipment enables to effectively determine deposit borders and depth. It also gives information about the physical properties of rock. The results may be used as drilling complementary information or autonomous source of geological data. The examples of electrical resistivity imaging application presented in the paper relate to data collected in order to determine the profitability of plot purchase before the exploitation process or deposit ceiling depth and weathering zones in existing mines. The aim of the measurements was to gain geological information on various rock types – basalts, limestones, dolomites and sand-gravel sediments.

19

Application of electrical and electromagnetic methods to study sedimentary covers in high mountain areas

Tomecka-Suchoń S., Żogała B., Gołębiowski T., Dzik G., Dzik T., Jochymczyk K.

Acta Geophysica

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2017

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Vol. 65, no. 4

743--755

EN

The results of geophysical studies conducted with selected electrical and electromagnetic methods in the Kondratowa Valley in the Tatra Mountains (the Carpathian Mountains, Poland) are presented in the article. The surveys were performed with the following methods: electrical resistivity tomography (ERT), georadar (GPR) and conductivity meter (CM). The objective of the noninvasive geophysical measurements was to determine the thickness of the Quaternary postglacial sediments that fill the bottom of the valley and to designate the accumulation of boulders deposited on Quaternary sediments. The results of ERT surveys conducted along the axis of the valley allowed to determine the changeability of the thickness of the postglacial sediments and allowed to designate a few areas of occurrence of boulders. The ERT, GPR and CM surveys conducted across the valley allowed to designate with high accuracy the thickness of the accumulation of boulders sliding down the valley bottom from the couloirs surrounding the valley.

20

Mapping of the north-eastern part of Kozłowicka buried valley based on geoelectrical data

Topolewska S., Stępień M., Kowalczyk S.

Studia Quaternaria

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2016

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Vol. 33, Nr 2

91--101

EN

The paper is aiming to determinate the extent of the northeastern arm of Kozłowicka buried valley on the grounds of own research by means of electrical resistivity tomography – ERT and available archival researches. On the Hydrogeological map of Poland, Żyrardów sheet (Felter and Nowicki, 1998a, b) Kozłowicka buried valley was differentiated as an individual hydrogeological unit. The results of the analysis show that the extent of the structure, defined by its upper boundary, differs significantly from the one suggested on the sheet of Hydrogeological map of Poland. Since there was no data available in the northeastern part of the discussed arm of Kozłowicka buried valley, the northern boundary was defined only based on available geoelectrical sounding profiles (Czerwińska, 1988; Topolewska, 2015). In order to confirm suggested solution, geoelectrical research by means of electrical resistivity tomography (ERT) was conducted. The measurements were performed along 3 profiles located in the area of interest. The authors would like to point out the need of the usage of ERT in mapping and studying buried structures that might be groundwater reservoirs. As a result, one obtains quasi-continuous image of electrical resistivity of the subsurface. Due to the contrast of electrical properties of sediments, it is possible to determine upper and bottom surfaces of electrical properties sediments, it is possible to determine upper and bottom surfaces of buried structures, formed within glacial deposits.