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PL
Tereny dawnej płytkiej eksploatacji górniczej na obszarze Górnego Śląska są szczególnie zagrożone deformacjami nieciągłymi. Staje się to szczególnie istotne na obszarach już zabudowanych oraz takich, gdzie planuje się ich zabudowę. Jednym z obszarów dawnej intensywnej płytkiej eksploatacji węgla są tereny w obrębie miasta Chorzów. Zostały one zabudowane w XIX i XX wieku, często w rejonach położonych nad płytko zalegającymi chodnikami lub innymi wyrobiskami podziemnymi. Stateczność takich wyrobisk oraz nadległych skał stropowych zabezpieczała w przeszłości ich obudowa. Niestety pod wpływem różnych procesów z czasem następuje utrata jej własności nośnych, czego przejawem są lokalne zawały stropu, a następnie deformacje dochodzące do powierzchni terenu. Stateczność takiego podłoża, a także możliwość zabezpieczenia konstrukcji obiektu budowlanego, jest zależna od jego aktualnych cech strukturalnych. Jedną z metod pozwalających na szczegółowe rozpoznanie struktury podłoża na terenach występowania płytko położonych wyrobisk górniczych jest metoda georadarowa. W artykule przedstawiono możliwości i analizę wyników badań wykonanych tą metodą na terenie pogórniczym, gdzie planowana jest budowa nowego obiektu, który to teren w przeszłości był już objęty pracami uzdatniającymi.
EN
The areas of Upper Silesia are threatened by possible deformations caused by old shallow mining. This becomes particularly important in areas already built-up and those that are planned. to be built-up. Chorzów City is one where shallow mining exploitation was very intensive. In the past, the stability of such galleries and a rock mass were protected by housing of these galleries. Under the influence of weathering processes, the housing lose its properties what is the reason of local roof falls occurrence and deformations of the surface. The stability of such a substrate as well as the possibility of securing the structure of a building object depends on its current structural features. The GPR method is one of the methods that allows detailed identification of the structure of the ground with shallow mining pits. The article presents an analysis of the results of research using this method for post-mining area on which the construction of a new facility is planned and which in the past was already covered by treatment works.
EN
The aim of this study was to identify the tile drainage systems within the year (from spring to autumn) using the ground penetrating radar (GPR) geophysical method. The measurements were performed in the experimental locality Dehtáře in the Bohemo-Moravian Highland (Czech Republic) in the years 2016 and 2017. The profiles located in the drained area were repeatedly measured together with the drainage discharges, soil moisture and groundwater level. The best visibility of tile drains was observed during snowmelt (in March and April) when the drainage discharges usually reach their maximum. In other months, the visibility of the drains was variable, but mostly worse. For a reliable detection of individual drains, the measurements above the drainage must be performed in several profiles. Under the conditions of the Czech Republic, the best results were obtained by a 500 MHz frequency antenna.
EN
From the construction made in the “white box” technology, first of all tightness is required - on the structural elements there should not be any cracks or scratches, through which water could penetrate, which in consequence may lead to deformation of structural elements and even loosing of their load-bearing capacity. Among the methods enabling the location of weakened places in watertight concrete, the ground penetrating radar (GPR) method is effective because the local occurrence of water in the structure evokes a clear and unambiguous anomaly on the radargram. In addition, the GPR method allows you to indicate places where water flows without the necessity of excluding the object from use and interference in the construction layers. The designation of such locations will make it possible to undertake technical activities that can facilitate the takeover of water and thus ensure the desired load-bearing capacity and usability of the object. Using the GPR method, you can also designate places that have already been deformed – discontinuities or breaking. The article presents a case study of investigations that determine the causes of leakage of tunnels made in the “white box” technology in: twice within the bottom slab of the tunnel (1 GHz air-coupled and 400 MHz ground-coupled antenna) and once in the case of tunnel walls (1.6 GHz ground-coupled antenna).
PL
Od konstrukcji wykonanej w technologii "białej wanny" wymagana jest przede wszystkim szczelność - na elementach konstrukcyjnych nie powinno być żadnych pęknięć ani zadrapań, przez które woda może przenikać, ponieważ to w konsekwencji może prowadzić do deformacji elementów konstrukcyjnych, a nawet utraty ich nośności. Wśród metod umożliwiających lokalizację osłabionych miejsc w wodoszczelnym betonie, metoda georadarowa (ang. ground penetrating radar - GPR), jest skuteczna, ponieważ lokalne występowanie wody w strukturze wywołuje wyraźną i jednoznaczną anomalię na otrzymanym obrazie (radargramie). Ponadto metoda GPR pozwala wskazać miejsca, w których woda przepływa bez konieczności wyłączania obiektu z użytkowania i bez ingerowania w warstwy konstrukcyjne. Wyznaczenie takich miejsc umożliwia podjęcie działań technicznych, które mogą ułatwić przejęcie wody, a tym samym zapewnić pożądaną nośność i użyteczność obiektu. Za pomocą metody GPR można również wyznaczyć miejsca, które zostały już zdeformowane – miejsca nieciągłości lub ugięć czy spękań. Artykuł przedstawia studium przypadku oraz badania, które umożliwiły określenie przyczyny wycieku w obrębie tunelu wykonanego w technologii "białej wanny" - w obrębie płyty dennej tunelu (z wykorzystaniem anteny o częstotliwości 1 GHz sprzężonej z powietrzem oraz z wykorzystaniem anteny o częstotliwości 400 MHz sprzężonej z ziemią), jak również w przypadku ścian tunelu (antena o częstotliwości 1,6 GHz sprzężona z ziemią).
PL
Aby poprawić działanie czujnika wizyjnego w procesach chemicznych, zaproponowano metodę jego modelowania opartą na ulepszonym podejściu wielomodelowym, w którym nie tylko wybrano zmienne modelowania o największym wpływie na zmienne dominujące na podstawie podobieństwa cosinusa, lecz także określono model czujnika wizyjnego. Przygotowane zmienne modelowania połączono za pomocą maszyny wektorów wspierających metodą najmniejszych kwadratów w celu oszacowania zmiennych elementów badanej próbki. Ponieważ mechanizm wyboru zmiennych modelowania wykorzystywał informację dynamiczną o procesach chemicznych, metoda ta okazała się bardziej od innych odpowiednia do szacowania danych. W celu weryfikacji modelu zastosowano rzeczywiste dane z urządzenia do odzysku siarki. Wyniki potwierdziły skuteczność zaproponowanej metody.
EN
To improve the soft sensor performance in chem. processes, a soft sensor modeling method based on improved ensemble learning that not only selected modeling variables with the highest influences on dominant variables by cosine similarity but also established the multi-target soft sensor model was proposed. The prepd. modeling variables were combined via the least squares support vector machine to predict the variable elements of the query sample. Because the variable selection mechanism of modeling used the dynamic information of chem. processes, this method was more suitable for data prediction than the other ones. Real data from a S recovery unit were used for model verification to evaluate the performance of the proposed soft sensor modeling method. The results confirmed its effectiveness.
5
Content available remote Geometryzacja form zjawisk krasowych na podstawie badań metodą georadarową
EN
Recognition of subsoil in areas threatened with discontinuous deformation associated with the existence of natural and mining voids can be implemented by various geophysical methods. The purpose of such research, apart from confirming the existence of voids, is to determine their spatial extent. This is not a simple issue, regardless of the geophysical method used. This paper discusses the possibilities of geometrization of karst phenomenon localization using the ground penetrating radar (GPR) method by the example of a karst cave as a natural void. The area of data acquisition is located on limestone formations with numerous karstforms. The study object is the main hall of the karst cave with a height of up to 3 m, located at a depth of 3 to 7 m below the surface. Such location and shape of the subsurface structure made it possible for the author to perform a wide range of research. Their original aspects are presented in this paper. The shape of the hall was obtained using terrestrial laser scanning (TLS). The GPR data were obtained employing the 250 MHz shielded antenna that was directly positioned using a robotized total station with the option of automatic target tracking. Thus, the GPR and geodetic data were immediately achieved in a uniform coordinate system. The accuracy of the data obtained in this way is discussed in this paper. The author’s original algorithm for processing of GPR data into a point cloud is presented. Based on the results obtained, it was possible to compare the GPR signal, which represents the shape of the cave hall, in relation to its image in the form of a point cloud from terrestrial laser scanning. A unique part of this paper is the selection of filtration procedures and their parameters in optimal GPR data processing, which were widely discussed and documented in a way beyond the standard filtration procedures. A significant contribution is the analysis that was carried out on the data obtained in the field and on the model data generated using the finite difference method. Modeling was carried out for two wave sources: exploding reflector and point. The presented methodology and discrimination between the actual shape of the cave, GPR field data and model data made it possible for the author to draw many conclusions related to the possibilities of shape geometrization of the subsurface voids determined by the GPR method.
EN
Utilizing the software-defined radio (SDR) technique is very common for developing ground penetrating radar (GPR) prototypes. A lowcost SDRs neither allow phase difference estimation between transmitter (Tx) and receiver (Rx). Consequently, direct exploitation of cheap SDRs for GPR is inaccessible. In the paper, an additional calibration step is taken in order to avoid phase difference measurement. The obtained imaging confirms that construction of a simple low-cost subsurface radar is feasible on the basis of the proposed approach.
PL
Wykorzystanie radia programowalnego (SDR – ang. Software Defined Radio) do prototypowania radarów penetracji gruntu (GPR – ang. Ground Penetrating Radar) jest bardzo powszechne. W tanich platformach SDR różnica fazy pomiędzy torem nadawczym i odbiorczym nie jest znana. Dlatego bezpośrednie zastosowanie tanich SDR do GPR jest niemożliwe. W artykule zastosowano dodatkowy krok kalibracyjny w celu uniknięcia pomiaru różnicy faz. Otrzymane zobrazowania potwierdzają możliwość konstrukcji taniego radaru do sondowań podpowierzchniowych.
EN
Lesser Poland (Małopolska) is a historic region of Poland. The presented case study was undertaken in the All Saints’ Church in the town of Szydłów, in which conservation and restoration works were carried out to preserve Gothic wall paintings by identifying and eliminating the causes of their degradation, and these efforts were supported by geophysical surveying. The conducted studies constitute a step not only to determine the age of the construction of the Szydłów temple, but also to improve knowledge of medieval architecture and mural paintings in Lesser Poland. The geophysical research with application of GPR (Ground Penetrating Radar) helped to locate previously unknown structures under the temple floor. This survey indicated four, possibly connected, structural objects clearly visible in GPR profiles. Carried out works confirmed that anomalies visible on radargrams mark two crypts. This discovery of the hidden construction elements emphasizes and strengthens the earlier suppositions of the unique character of this temple.
EN
In order to assess Ground penetrating radar (GPR) for imaging the shallow subsurface geometry and characteristics of the fault in Yushu area, details GPR measurements with 25 MHz, 100 MHz and 250 MHz frequencies antenna were firstly conducted in four sites along the Yushu fault after geomorphologic and geological investigation. The 25 MHz profiles delineated an excellent general view of deformation zones at a much wider area and greater depth. While the 100 MHz and 250 MHz data provided more detailed analysis of the shallow subsurface deformation about the geologic structure and the fault, including the stratigraphic structures, the dip angle and direction of the fault plane. The remarkable variation in the pattern and relative amplitude of electromagnetic waveform on the two-dimensional GPR profiles are all obvious and it is considered as the main fault zone with a nearly vertical fault with the dip angle of 70°–85°. High frequency GPR profiles show a good consistency with the trench sections at three sites. The geometry of the main fault zone can be depicted and deduced up to ~ 12 m deep or even deeper on the 25 MHz GPR profile in Yushu area and it is considered to be the result of the movement of active faults. What’s more, the geophysical features on GPR profile associated to the strike-slip fault are further summarized in different geological and geomorphological environment in Yushu area, the study also provides further evidence that GPR is valuable for fault investigation and palaeoseismic study in the Qinghai-Tibet Plateau area.
EN
The main goal of the work is to create an automatic method of locating weak zones within flood embankments structure based on ground penetrating radar (GPR) measurements. The presented research shows the possibilities of using advanced methods of GPR signal processing and its analysis with the help of signal attributes for detecting zones threatening the stability of the structure of flood embankments. Obtained results may help in quick detection of potential weak zones of the embankments and consequently give means to ameliorate them, which may prevent damage to the embankments during rise in the level of river water. The presented analyses were carried out on GPR data obtained for the flood banks of the Rudawa River (Kraków, Poland) in the area of their visible degradation. The use of signal attributes, such as Energy, instantaneous frequency, similarity, curvature gradient, dominant frequency, allowed initial indication of anomalous zones threatening the stability of embankment. Advanced processing supported by the use of advanced filters such as GLCM, Grubbs filter threshold and Convolve Prewitt helped in the analysis of the structure of the embankments. Artificial neural networks (ANNs) in the supervised and unsupervised variants were used to perform the automatic classification of weakened zones within the embankments. The results demonstrated the usefulness of GPR geophysical method through integration of ANN in the analysis of the data.
EN
In this study, we investigated the relationship between ground-penetrating radar (GPR) response and agriculture properties of soil with a view to understanding how the constraint of soil degradation may influence the properties. GPR field data measurements were made at a location with soil types, properties, and disturbances caused by tractor movement. The data were processed, and empirical equations relating soil physical properties and material properties of soil media were considered for the analysis of the field data. The results showed a change in the reflection coefficient and increase in the GPR wave velocity when comparing the records of the initial parts of the GPR records, lasting about 2.5 ns, of the signal response of soil subjected to compaction as a result of 10 tractor passes, with those obtained prior to movement of the tractor. The summation of the absolute value of GPR wave amplitude in the analyzed results clearly shows that the amplitude of the signal corresponding to the compressed ground is twice and even three times smaller than the amplitude recorded before the tractor runs. The results prompted the design of a relatively simple method for tracking changes in soil properties based on the results of GPR measurements, which show that zones subjected to direct tire pressure are easy to delineate and are not limited to the part that is directly under the tire, but extend about 0.5 m. It thus shows that there is a relationship between the penetration resistance induced by a change in porosity and changes in the coefficient of reflectivity and the velocity of radar waves.
EN
Presented study gives an insight into general proportions of the actual geomorphology, subglacial morphology and thickness of the drift (quaternary sediments) particularly well-pronounced glacial morphology in the Tatras and, on the other hand, the general scarcity of the data in this field. Objectives of the geophysical survey in this study were imaging of the morphology of bedrock surface under the drift (glacial and postglacial) sediments and determination of thickness of the drift and its composition. Two methods were applied: Ground Penetrating Radar (GPR) and seismic refraction profiling. GPR was used to examine drift sediments due to its high resolution and low depth of penetration. Seismic method with lower resolution but higher penetration depth gave an image of boundary between bedrock and drift. In addition, the results of seismic tomography allowed the velocity field imaging which shows changes inside the postglacial deposits. The results of the two methods used in this research suggest that points of depression exist in the subglacial morphology with a depth of about c.a. 40 below the present-day terrain surface and c.a. 25 m below surrounding subglacial surface. This trough has also been estimated to be about 150 m wide. Its considerable depth and steep slopes show that its origin can be related to erosion of subglacial water during the decay of the last (Würm) glaciation of the Sucha Woda and Panszczyca valleys.
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.
13
Content available remote The application of non-standard GPR techniques for the examination of river dikes
EN
A standard measurement procedure currently applied in the ground penetrating radar (GPR) method is shortoffset reflection profiling. As this procedure delivers data that is suited only for qualitative interpretation, its application should be limited exclusively to reconnaissance surveys. There are various other techniques used in GPR surveying that may be regarded as non-standard, such as multi-offset and adaptable-polarisation surveying and tomography. Because these techniques deliver information that allows for quantitative interpretation, they could be applied for the detailed examination of geological media and investigations of various buried anthropogenic targets. This paper focuses on the application of non-standard GPR techniques for the detection of high-porosity zones in river dikes. Results from both field surveys and numerical modelling are presented.
PL
Standardową techniką pomiarową stosowaną obecnie w metodzie georadarowej (GPR) jest krótkooffsetowe profilowanie refleksyjne. Technika ta dostarcza jedynie informacji do interpretacji jakościowej, więc powinna być stosowania tylko w badaniach rekonesansowych. W metodzie GPR jest kilka technik pomiarowych, które można uznać obecnie za niestandardowe, tzn. badania zmienno-offsetowe i zmiennopolaryzacyjne oraz tomografia otwór–otwór i otwór–powierzchnia. Techniki niestandardowe dostarczają informacji do interpretacji ilościowej więc powinny być stosowane w szczegółowych badaniach ośrodka geologicznego i obiektów antropogenicznych. W artykule skupiono się na zastosowaniu niestandardowych technik pomiarowych do wykrywania stref podwyższonej porowatości w wałach przeciwpowodziowych. W pracy przedstawiono wyniki pomiarów terenowych oraz modelowań numerycznych.
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.
PL
Zawilgocenie nawierzchni drogowej wpływa negatywnie na jej właściwości mechaniczne. Dostępne są różne metody oceny nawierzchni drogowych pod kątem zawilgocenia. Najprostsze w interpretacji metody grawimetryczne wymagają inwazyjnej ingerencji w stan nawierzchni i pomiarów wagowych w warunkach laboratoryjnych pobranych próbek. Istnieją także metody nieniszczące, m.in. metoda georadarowa. W artykule przedstawiono ocenę zawilgocenia za pomocą metody georadarowej na odcinku drogi długości 200 m, prowadzącej przez tunel wybudowany w technologii „białej wanny” z nawierzchnią w postaci warstwy asfaltowej grubości 12 cm, ułożonej na warstwie kruszywa grubości 20 cm. Po ok. pięciu latach użytkowania drogi zaobserwowano na niej wysięki w postaci mokrych plam. Zauważono także deformację w formie wyniesienia (wybrzuszenia) warstw asfaltowych. Georadar umożliwił zlokalizowanie miejsc zawilgoconych w obu warstwach nawierzchni drogowej i podanie przyczyny powstawania deformacji i wysięków wody na nawierzchni drogi.
EN
The presence of water in the road structure has a negative impact on its mechanical properties. Various methods are available for assessing roads in terms of their humidity. The simplest in interpretation - gravimetric methods - require invasive intervention in the road condition and measurements of weights of the samples in laboratory conditions. There are also non destructive methods, among them the Ground Penetrating Radar (GPR). The article presents the assessment of moisture using the GPR on a 200-meter section of the road leading through a tunnel built in the „white box” technology with road surface built of 12-centimeter of asphalt layer on 20-centimeter of aggregate. After about 5 years of use, there were wet spots on the road and deformation of asphalt layers in the formof elevation. GPR made it possible to locate wet areas in both layers and point the probable reasons of the deformation and wet spots on the road surface.
PL
W artykule przedstawiono możliwość wykorzystania metod nieniszczących w diagnostyce nawierzchni drogowych jako alternatywę do metod tradycyjnych w celu wyjaśnienia przyczyn powstawania zarysowań poprzecznych nawierzchni w sąsiedztwie obiektów mostowych. Wykorzystano dwie metody skanowania: laserowe w celu szczegółowej inwentaryzacji powierzchni nawierzchni oraz georadarowe (GPR) w celu inwentaryzacji struktury nawierzchni. W wyniku zastosowania skanowania laserowego obszarów w rejonie dylatacji obiektów mostowych, które wykonywano z dokładnością około 3 mm, otrzymano przestrzenną mapę geometrii. Otrzymane wyniki zobrazowano w postaci mapy graficznej oraz przekrojów poprzecznych przedstawiających odchyłki od idealnej założonej w projekcie powierzchni. Skanowanie georadarowe wraz z postprocessingiem miało na celu wykrycie ewentualnych nieciągłości w strukturze warstw nawierzchni powyżej płyty przejściowej. Wykorzystano do tego analizę przewodności poszczególnych warstw. Badania wykonane metodami nieniszczącymi weryfikowano z wykorzystaniem standardowych testów związanych z badaniem i pobieraniem próbek rdzeniowych nawierzchni. W wyniku pomiarów georadarowych i analizy pobranych próbek otrzymano zgodne wyniki. Wskaźniki zagęszczenia poszczególnych warstw były znacznie mniejsze w rejonie przyczółka niż w odległości kilku metrów od niego. Pomiary wykazały występowanie zarówno błędów projektowych, jak i związanych z budową konstrukcji nawierzchni.
EN
The article presents the potential of using the non-destructive methods of road pavement diagnostics as an alternative to traditional means of assessing the causes of transverse cracks in pavements adjacent to bridge structures. Two scanning methods were used: laser scanning to measure geometric surface deformation and ground penetrating radar (GPR) inspection to assess the road pavement condition. With the use of a laser scanner, as an effective tool for road deformation assessment, several approach pavement surfaces near bridges were scanned.
EN
Sand dunes are the most prominent subjects of geological and geomorphological interest along the Curonian Spit - a mega-barrier that separates the Curonian Lagoon from the Baltic Sea. To date, an assessment of various parameters of migrating dunes along the spit has been based on comparative analysis of old maps or aerial and satellite images, as well as geodetic measurements. These investigations have allowed assessment of dune dynamics over a relatively short historical period (~1700s to present). The most recent detailed investigations of the Dead (Grey) Dunes along the Lithuanian part of the spit using ground-penetrating radar (GPR) and magnetic susceptibility (MS) surveys, supported by a radiocarbon (14C) chronological framework of palaeosols and infrared optically stimulated luminescence (IR-OSL) ages of sand horizons, have advanced our understanding of aeolian landscape evolution. The interpretation of dune activity and stability phases has been generally based on IR-OSL dating results of the sand layers located between radiocarbon-dated palaeosols. However, the influence of soil-forming processes on the IR-OSL dating results related to possible migration of natural radioactive isotopes via aeolian sand layers has not been previously considered. Hypotheses of dune reactivation and migration caused by abrupt regional climate shifts, catastrophic forest fires, anthropogenic influence, and more local forcings have been tested. An integrated approach to dune investigations has offered an estimate of the rates of sand accumulation and key phases of aeolian dynamics during both stormy and calm periods, as well as helped to extend the record of dune evolution to the mid-Holocene. The palaeoenvironmental and palaeodynamic reconstructions of the Dead Dunes suggest that this mid-Holocene phase of dune activity was of a local character and likely did not exceed several centuries.
EN
The Curonian Spit is one of the largest Holocene sand accumulation forms, stretching along the Baltic Sea coast and belonging to the Baltic sand belt. This article deals with the dynamics of the Curonian Spit dunes in the context of global climate change. Investigations were carried out in the environs of two high dunes (Parnidis Dune and Naglis Dune) over a period of 10 years (2003-2014). Levelling of cross-sections was performed using modern geodesic devices. Wind velocities and directions were measured at meteorological stations of Klaipeda and Nida. The wind regime (number of days with winds >15 m/s) was almost at the multiannual average during the study period. Sand moisture was measured in both dunes studied, and groundwater level was measured in the environs of the Naglis Dune by using ground penetrating radar (GPR). The Naglis Dune experienced a more significant lowering (by 4-6 m) compared with the Parnidis Dune over the study period, while sand deficit was greater in the Parnidis Dune (~10,000 m3). Compared with other European sand dune systems, the Curonian Spit dunes have undergone strong degradation. The article highlights possible degradation reasons and indicates the necessity of additional investigations. Only long-term investigations can contribute to disclosing the main processes both as natural background and due to anthropogenic activities, and the devising of protection measures.
PL
Technologia georadarowa (GPR) jest powszechnie stosowana do obrazowania obszarów podpowierzchniowych m.in. nawierzchni drogowych. Jest to metoda nieniszcząca, wykorzystująca do wykrywania sygnałów odbitych od konstrukcji podpowierzchniowych promieniowanie elektromagnetyczne w paśmie mikrofalowym. GPR transmituje do ziemi fale elektromagnetyczne, a gdy te uderzą w zakopany obiekt lub granicę materiałów o różnych stałych dielektrycznych, antena odbiorcza rejestruje zmiany w sygnale zwrotnym. Ważne jest, aby mieć podstawową wiedzę na temat działania georadaru, ponieważ jego możliwości, ale i ograniczenia są bezpośrednio skorelowane z nauką. W artykule charakteryzowano technologię georadarową ze zwróceniem szczególnej uwagi na ograniczenia stosowania metodologii. Opisuje możliwości zwiększenia efektywności pomiarów georadarowych i nowe obszary zastosowań.
EN
Ground Penetrating Radar (GPR) technology is widely used for imaging the subsurface areas, including road structures. It is a non-destructive method that uses electromagnetic waves to detect signals reflected from sub-surface constructions. GPR transmits electromagnetic waves to the ground, and when these hit a buried object or boundary of materials with different dielectric parameters, the receiving antenna registers changes in the reflected signal. It is important to have a basic knowledge related to the operation of GPR, because its capabilities, but also limitations are directly correlated with science. The article describes GPR technology with particular attention to the limitations of the methodology. It describes the possibilities of increasing the GPR efficiency and new areas of applications.
EN
The west channel of the ancient Deák Ferenc which was constructed in 1875 in Hungary was used for controlling the water amount and the east channel was used for the shipping. In the study, four geophysical nondestructive methods were used to this old channel which needs the restoration and reinforcement works. The high-frequency seismic and acoustic measurements were carried out, the resistivity measurements were carried out to map the resistivity distribution of the slab, the seismic direct wave method was used to map the seismic velocities for understanding the stability conditions of the walls and the ground penetrating radar measurements were carried out on the slab and on the walls. The results of integrated study showed us that voids, faults and cracks were detected and the inhomogeneous construction materials were used in the slab. The obtained results emerged that the usage of nondestructive geophysical methods is essential in all stages of restoration and reinforcement works, especially for the ancient structures.
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