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PL
Ochrona zabytkowych budynków wymaga metod nieniszczących oceny ich stanu. Metoda georadarowa (GPR) i termograficzna (IRT) wyłoniły się jako uzupełniające techniki badania obiektów dziedzictwa kulturowego. W niniejszym badaniu analizowano zintegrowane zastosowanie metod GPR i IRT w celu poprawy wykrywania ukrytych cech w budynku zabytkowym. Techniki GPR i IRT są szeroko stosowane w diagnostyce ze względu na ich zdolność do wykrywania ukrytych anomalii strukturalnych badanych elementów bez fizycznej interwencji. Zintegrowane wykorzystanie GPR i IRT pozwala na wizualizację inkluzji i różnicowanie materiałów. W niniejszym artykule przedstawiono wyniki badań eksperymentalnych przeprowadzonych w Kolegiacie Najświętszego Serca Jezusowego w Gdańsku. Wykonano obrazowanie wewnętrznej struktury częściowo zrekonstruowanego sklepienia. Wyniki podkreślają potencjał integracji GPR-IRT jako skutecznego, nieinwazyjnego podejścia do inspekcji zabytkowych konstrukcji.
EN
The protection of historic buildings requires non-destructive methods to evaluate their condition. Ground penetrating radar (GPR) and infrared thermography (IRT) have emerged as complementary techniques for the examination of cultural heritage structures. This study explores the integration of GPR and IRT to improve the detection of hidden features in historic buildings. GPR and IRT techniques are widely used in diagnostics due to their ability to reveal underlying structural anomalies of tested elements without physical intervention. The integrated use of GPR and IRT allows the visualisation of hidden inclusions and the differentiation of materials. This paper presents the results of experimental investigations carried out in the Collegiate Church of the Most Sacred Heart of Jesus in Gdańsk. The internal structure of the partially reconstructed vault was imaged. The results highlight the potential of GPR-IRT integration as a powerful, non-invasive approach for the inspection of historical structures.
EN
Ground penetrating radar (GPR) is a very useful geophysical method for use in hydrogeologic and near-surface mapping studies. It can be used to study contaminants in groundwater, subsurface faulting, and underground cavities (natural or man-made), all of which pose potentially dangerous geological hazards. The GPR technique is similar in principle to seismic reflection and sonar techniques. The propagation of the radar signal depends on the frequency-dependent electrical properties of the ground.Electrical conductivity of the soil or rock materials along the propagation paths introduces significant absorptive losses which limit the depth of penetration into the earth formations and is primarily dependent upon the moisture content and mineralization present.Reflected signals are amplified, and transformed to the audio-frequency range, recorded, processed, and displayed. From the recorded display, subsurface features such as soil/ soil, soil/rock, and unsaturated/saturated interfaces can be identified. In addition, the presence of floating hydrocarbons on the water table, the geometry of contaminant plumes, and the location of buried cables, pipes, drums, and tanks can be detected. The GPR data are presented as a twodimensional depth profile along a scanned traverse line in which the vertical axis is two-way travel time measured in nanoseconds. The location of hydrocarbon contamination in the ground using the GPR method is based mainly on information taken from reflected signals. In the cases investigated in Romania contaminated sites (Navodari area), such signals were very rarely recorded. A long time after spillage, contamination takes the form of plumes with different size and distribution, which depends on the geological and hydraulic properties of the ground. The survey discussed in this paper was carried out using the GPR system-Noggin with two antennas (250 and 500mHz) Data collected were processed using software(EKKO_Project™ GPR Data Analysis) to produce 2D radargram in time scale. The presence of contaminant plumes as well as the water table are observed in the GPR sections at depths approximately of 0.5 to 1.5 m. In the GPR section, the oil contaminated layer exhibits discontinuous, subparallel, and chaotic high amplitude reflection patterns. Promising results were also obtained in the GPR survey where three obvious reflection patterns representing the top sand-silt layer, oil-contaminated zone and, the underlying thick soft clay were detected in all 2D radargrams of the GPR traverse lines.
EN
One of the recurrent problems in civil construction concerns the wear and deterioration of structures due to their use over time. There should be a plan for monitoring the structures to assess and quantify anomalies, which will allow the minimization and rehabilitation measures to be carried out in advance. This study aimed to use geotechnologies, specifically the Ground Probing Radar (GPR), to identify and quantify the damage caused using a swimming pool inserted in a structure built on a residential property. The methodology comprised the use of georradar Sensors & Software PulseEKKO GPR for data acquisition. The data were processed in the software EKKO Project considering the following parameters: 1- Grain/Filter: Dewow + SEC2 Gain (Attenuation:10.00 Start Gain:4.00 Maximum Gain: 950). Seven acquisition profiles were performed: 3 on the East side, 2 on the South side, and 2 on the West side of the pool, with a spacing between 0.8 m. From the visualization of the processed radargrams, and the slices elaborated for each profile with a color palette corresponding to the obtained reflectance values, it was possible to identify the underlying structures of the pavement of the edge of the pool such as beams, beam frames, slope, interior space of the support structure and, most importantly, the degree of subsoil materials alteration, depth, and dispersion of water infiltrations. On the East side, the pool is inserted into the rock formation; it is possible to identify up to 1 m depth of the water infiltration and dispersion. To the West and South, the pool is supported by a built-up structure; underneath there is a hall and the engine room. In these places, the infiltration and dispersion of water were identified until approximately 0.7 m depth, as well as the existing structures and their condition. The 0.7 m corresponds to the thickness of the existing slab and beams. Based on these results, an intervention plan was prepared for the rehabilitation of the deterioration of the materials and the minimization of water percolation through the waterproofing of the pool's surrounding areas.
EN
Widely used in civil engineering, GPR (ground penetrating radar) is increasingly being used to survey historic structures. However, there are still no conclusive directives on the use of GPR in the identification and diagnosis of masonry structures. The current state of the art allows only on the example of individual case studies, to draw conclusions about the effectiveness of the use of this tool. One such area, where the effective use of GPR has been experimentally confirmed, is the historic architectural survey of a heritage buildings. Due to diversity in the dielectric properties of individual construction materials, it is possible to observe on radar grams the change of electromagnetic wave patterns by materials from different phases. Traditional approach require extensive excavation efforts or core drilling, which may not always be acceptable for conservation reasons. Hence the GPR method could be interesting, non – destructive option for identification and diagnosis of historical masonry walls. The authors used the architectural survey and accompanying excavations at the former Piast Gymnasium in Brzeg to conduct a survey campaign using the GPR method. The brick walls of the building's nave have been scanned. The nave have undergone numerous alterations over hundreds of years. The GPR data has been subjected to adequate post-processing and then correlated with architectural surveys and validated on the basis of available excavations at the site. The authors highlight that GPR surveys, when combined with architectural investigations, offer a less invasive approach to examining historic structures, thereby mitigating the need for problematic excavation work.
EN
Data synergy involves acquiring and combining data from different sensors to achieve better problem analysis and research results. For more comprehensive data analysis, the sensors are not only mounted on one platform. Still, they should also be compatible with software and hardware, e.g. for the same timestamp registration by different sensors. The aim of this article is to propose the synergy between various remote sensing sensors including the ground penetrating radar (GPR), LiDAR (Light Detection and Ranging) sensor and three photogrammetric RGB cameras for damage detection in a pavement in a park alley. The data were acquired with a low-cost platform, in the Pole Mokotowskie Park in Warsaw, Poland. Three drives were made along the same path with the platform, so it was possible to assess the repeatability of the data. Based on the GPR data, orthophotomap, and digital terrain model (DTM) from images, an analysis of the cracks in the pavement was done. The paper proves additive value from the synergy of data collected for the alley also in the form of a common visualization of acquired data. Results presented in the article showed that using mobile mapping platform and technologies describing the situation above and below the ground level enable a more detailed analysis and inspection of the damages in the park alley.
PL
Synergia danych obejmuje pozyskiwanie i łączenie danych z różnych sensorów w celu wykonania lepszej jakości analiz i uzyskania lepszych wyników badań. W celu zapewnienia bardziej kompleksowej analizy danych, oprócz tego, że sensory są montowane na jednej platformie, powinny być one również kompatybilne z oprogramowaniem i sprzętem, np. w celu rejestracji tego samego znacznika czasu przez różne sensory. Celem tego artykułu jest zaproponowanie synergii między różnymi sensorami teledetekcyjnymi, z georadarem (GPR), czujnikiem LiDAR (Light Detection and Ranging) i trzema fotogrametrycznymi kamerami RGB do wykrywania uszkodzeń chodnika w alejce parkowej. Dane zostały pozyskane za pomocą niskokosztowej platformy w parku Pole Mokotowskie w Warszawie. Wykonano trzy przejazdy platformą po tej samej trasie, dzięki czemu możliwa była ocena powtarzalności danych. Na podstawie danych z georadaru, i numerycznego modelu terenu (NMT) ze zdjęć przeprowadzono analizę pęknięć w nawierzchni. W artykule udowodniono wartość dodaną wynikającą z synergii również w postaci wspólnej wizualizacji pozyskanych dla chodnika danych. Wyniki przedstawione w artykule wykazały, że wykorzystanie mobilnej platformy oraz technologii opisujących sytuację nad i pod poziomem gruntu umożliwia bardziej szczegółową analizę i inspekcję uszkodzeń w alejce parkowej.
EN
Precise determination of the location of underground utility networks is crucial in the field of civil engineering for: the planning and management of space with densely urbanized areas, infrastructure modernization, during construction and building renovations. In this way, damage to underground utilities can be avoided, damage risks to neighbouring buildings can be minimized, and human and material losses can be prevented. It is important to determine not only the location but also the type of underground utility network. Information about location and network types improves the process of land use design and supports the sustainable development of urban areas, especially in the context of construction works in build-up areas and areas planned for development. The authors were inspired to conduct research on this subject by the development of a methodology for classifying network types based on images obtained in a non-invasive way using a Leica DS2000 ground penetrating radar. The authors have proposed a new classification algorithm based on the geometrical properties of hyperboles that represent underground utility networks. Another aim of the research was to automate the classification process, which may support the user in selecting the type of network in images that are sometimes highly noise-laden. The developed algorithm shortens the time required for image interpretation and the selection of underground objects, which is particularly important for inexperienced operators. The classification results revealed that the average effectiveness of the classification of network types ranged from 42% to 70%, depending on the type of infrastructure.
PL
Precyzyjne określenie położenia podziemnych sieci uzbrojenia terenu jest kluczowe w dziedzinie inżynierii lądowej w zakresie prac modernizacyjnych infrastruktury, podczas budowy i remontów obiektów oraz przy planowaniu i zarządzaniu przestrzenią o gęstej urbanizacji. Wiele zadań administracji publicznej takich jak: pozyskiwanie gruntów, zarządzanie własnością i planowanie zależy od wiarygodności lokalizacji uzbrojenia podziemnego. Pozwala to uniknąć zniszczeń uzbrojenia podziemnego, zminimalizować ryzyko uszkodzeń sąsiednich budynków oraz zapobiec stratom ludzkim i materialnym. Ważne jest, aby określić nie tylko lokalizację, ale również rodzaj sieci uzbrojenia podziemnego. Informacja o lokalizacji i rodzajach sieci usprawnia proces projektowania zagospodarowania terenu i wspiera zrównoważony rozwój obszarów miejskich, zwłaszcza w kontekście prac budowlanych na terenach zabudowanych i planowanych do zabudowy w dziedzinie inżynierii lądowej. Motywacją autorów do podjęcia tematu badawczego było opracowanie metodyki klasyfikacji typów sieci na podstawie bezinwazyjnie pozyskanych obrazów georadarem Leica DS2000. Autorzy zaproponowali nowy algorytm klasyfikacji bazujący na cechach geometrycznych hiperbol reprezentujących sieci podziemne. Celem pracy była również automatyzacja procesu klasyfikacji, który może wspomóc użytkownika w wyborze typu sieci na czasami bardzo zaszumionych obrazach. Echogramy pozyskano w kilkunastu różnych lokalizacjach w Otwocku i na obszarze Wojskowej Akademii Technicznej w Warszawie. Opracowany algorytm pozwala na skrócenie czasu interpretacji obrazów i selekcji obiektów podziemnych, co jest szczególnie istotne dla niedoświadczonych operatorów. Wyniki klasyfikacji wykazały, że średnia skuteczność klasyfikacji typów sieci waha się w graniach od 42% do 70% w zależności od rodzaju infrastruktury podziemnej.
EN
Ground penetrating radar (GPR) is one of the most useful non-destructive techniques for locating underground objects. Advancements in this technology have facilitated the development of new sensors over the past decade. In this paper, an accuracy assessment of the location of underground objects using various GPR antennas is presented. To achieve the stated goals, measurements of 5 concrete slabs, reinforced with steel bars of various diameters and located at variable depths were taken. The experiment includes the usage of three GPR antennas to assess the format, characteristics, and differences of extracted data. This set of antennas from different manufacturers varied in terms of operating frequency. Additional lidar data from TLS (terrestrial laser scanning) was utilized in the methodology to provide precise surface measurements and therefore, external orientation of the surveyed data. The experiment allowed for the determination of vertical and horizontal accuracy for three tested antennas and the assessment of increasing errors value with greater depth of the measured items, which is important for surveying accuracy forecasting.
PL
Georadar jest jedną z najbardziej użytecznych nieinwazyjnych technik lokalizowania obiektów podziemnych. Postęp w tej technologii w ostatniej dekadzie ułatwił rozwój nowych sensorów. W artykule przedstawiono ocenę dokładności lokalizacji prętów zbrojeniowych znajdujących się w obrębie badanego obiektu z wykorzystaniem różnych anten. Aby osiągnąć założone cele, wykonano pomiary 5 płyt betonowych, zbrojonych prętami stalowymi o różnych średnicach i znajdujących się na różnych głębokościach. Eksperyment obejmował wykorzystanie trzech anten o różnej częstotliwości do oceny rozmiaru, charakterystyki i różnic wyodrębnionych danych. W metodyce eksperymentu wykorzystano dodatkowo dane lidarowe z naziemnego skanowania laserowego (TLS), aby zapewnić precyzyjne pomiary powierzchni, a tym samym zewnętrzną orientację przestrzenną pozyskanych danych. Eksperyment pozwolił na wyznaczenie dokładności pionowej i poziomej dla trzech wykorzystanych anten oraz ocenę rosnącej wartości błędów wraz z większą głębokością mierzonych elementów, co jest istotne dla predykcji dokładności pomiarów.
EN
The electrical resistivity, i.e. electrical resistivity tomography (ERT) and direct current-resistivity sounding (DC-ERS), and ground penetrating radar (GPR) methods were deployed to assess a gully erosion site in Bacoco area of Calabar, Nigeria. The study aims to assess the mechanism and dynamics of the gully erosion conditions in the area based on shallow lithostrati-graphic evaluations. The results revealed good contrast in the operative properties (i.e. electrical resistivity and dielectric permittivity) between competent and weak zones along the profiles close to the gully head. The joint interpretations provided reliable shallow subsurface models and lithologies that consist predominantly of lateritic top cover and sands. However, the ERT model delineates the contrast between lithologies and demarcates the weak zones from the relatively competent zones, in contrast to the responses generated by the GPR technique. This joint interpretation approach minimizes the uncertainty due to the non-uniqueness problems common to the geophysical technique. Also, the geophysical interpretations were constrained using lithologic information from the gully walls and one-dimensional (1-D) DC-ERS inverted model to provide additional validity. Our findings suggest the influence of structural control on gully formation and demonstrate its contribution to the complex interactions with other drivers, such as seepages through porous media and high-energy runoff due to intense rainfall. The rapid, non-invasive and environmentally friendly characteristics of ERT and GPR techniques favour their applicability in assessing shallow subsurface environmental problems.
EN
The article considers the issues of applying ground penetrating radar (GPR) technologies for engineering purposes concerning subsurface research. It describes the field of application of GPR research during road construction and operation and the advantages and disadvantages of this type of engineering survey. It presents comparative data on the accuracy (inaccuracy) of existing GPR control methods applied to determine the thickness of the monolithic pavement layers in Europe, CIS, and the USA. The main provisions of the GPR survey procedure are described, including four main stages: the analysis of initial materials of surveyed section and equipment preparation; GPR survey; geological verification; processing and interpreting of radargrams; and the preparation of a report. Geophysical works were performed using the geo-radar of the OKO series as part of the road measuring complex DVK-05 on the section of the Astana-Petropavlovsk A-1 highway with cement concrete pavement and on the section of the R-12 "Kokshetau - Atbasar" with asphalt pavement. The example of a radargram and the core sample of a cement concrete pavement taken during geological verification of the thickness of a monolithic layer is presented. Graphs of variation in the thickness of pavement layers by radargrams of longitudinal passages in the indicated road sections with the assumptions about the nature of the heterogeneity of the obtained values are given. The obtained results on the thickness of monolithic layers (cement concrete and asphalt concrete) were assessed on the criteria of quantitative deviation from the required standard value. Recommendations were provided to address positive deviations in the thickness of monolithic pavement layers at various stages of the road survey.
EN
Ground Penetrating Radar is commonly used in civil engineering sectors. Underground anomalies (i.e., electric wires, water pipes or sinkholes) can be detected through representations of hyperbolae in the measured processed GPR image. Our work focuses on detecting the underground objects and understanding their metallic or nonmetallic characteristics. The max energy difference attribute is applied to illuminate their positions while phase analysis process can determine change of phase spectrum in the diffracted signals. For improving phase analysis, we applied a novel workflow combining conventional processed steps and a zooming step for preserving phase originality without disturbed by any unnecessary filters. We applied the workflow in model and real data for proving its effectiveness. Interpretation of two real datasets in Vietnam by our workflow can express existences of the artificial underground anomalies as well as their matter characteristics comparing to their surrounding environments.
PL
Ground Penetrating Radar jest powszechnie stosowany w inżynierii lądowej i wodnej. Podziemne anomalie (np. przewody elektryczne, rury wodociągowe lub zapadliska) można wykryć za pomocą reprezentacji hiperbol w zmierzonym przetworzonym obrazie GPR. Nasza praca koncentruje się na wykrywaniu podziemnych obiektów i zrozumieniu ich metalicznych lub niemetalicznych wła-ściwości. Atrybut maksymalnej różnicy energii jest stosowany do oświetlania ich pozycji, podczas gdy proces analizy fazowej może określić zmianę widma fazowego w dyfrakcyjnych sygnałach. Aby usprawnić analizę fazową, zastosowaliśmy nowatorski przepływ pracy łączący konwencjonalne kroki przetwarzania i krok powiększania w celu zachowania oryginalności fazy bez zakłócania przez niepotrzebne filtry. Zastosowaliśmy przepływ pracy w modelu i rzeczywistych danych, aby udowodnić jego skuteczność. Interpretacja dwóch rzeczywistych zbiorów danych w Wietnamie za pomocą naszego przepływu pracy może wyrazić istnienie sztucznych anomalii podziemnych, a także ich charakterystykę materii w porównaniu z otaczającym je środowiskiem.
PL
Artykuł przedstawia zyskujące w ostatnim czasie na popularności i znaczeniu elektromagnetyczne metody nieniszczące badań (skanowania konstrukcji), indukcję elektromagnetyczną zwaną też metodą prądów wirowych (Eddy Current) i metodę georadarową (GPR). Przybliżono ich zasadę działania, możliwości i ograniczenia, a przede wszystkim porównano uzyskane nimi wyniki na podstawie przeprowadzonych przez autora skanowań.
EN
Article presents the recently gaining popularity and importance electromagnetic nondestructive concrete scanning methods, electromagnetic induction (also known as eddy current or Foucault’s currents) and ground penetrating radar (GPR). It discusses their principle of operation, possibilities and limitations, and above all compares the obtained results based on the scans performed by the author.
EN
The article presents some objectives and results of the European Defense Agency Program on: Improvised Explosive Devices Detection (IEDDET Program). The goal of the article is to describe the work, results and recommendations regarding Unmanned Ground Vehicle (UGV) and Ground Penetrating Radar (GPR) - contributions within the MUSICODE project. Its scope and goals were presented, which are in line with the objectives of the IEDDET Program taking into consideration that the recommendations (for UGV and GPR) are related to the goals, not the results of MUSICODE project. There were described scenarios and the resulting changes in the structure implemented in the UGV - the FLORIAN robot which served as a sensors carrier including Ground Penetrating Radar (GPR). The main focus of the article is to find the answer to the research question: what is an impact of using the GPR to be mounted on the UGV to detect improvised explosive devices (IEDs) on the UGV construction and the GPR results. The structure of this radar was described and examples of tests results were presented. The summary presents recommendations for the construction of an unmanned land platform to carry sensors used in the work carried out in the MUSICODE project and conclusions regarding GPR, resulting from the experiences gained under the IEDDET Program.
13
Content available A Review on Impulse RADAR
EN
RADAR plays a vital role in military applications since its origin in the 2nd world war. Recently it has been used in surface inception, health monitoring, infrastructure health monitoring, etc. In these applications, Ultra-wideband RADAR systems are more popular than traditional RADAR systems. Impulse RADAR is a special kind of ultra-wideband RADAR, which is mostly used for surface penetration, through-wall imaging, antimissile detection, anti-stealth technology, etc. because of its high resolution and low center frequency. Out of all these applications, impulse RADAR has been used intensively as a ground-penetrating RADAR for the detection of land mines, underlying pipelines, buried objects, etc. This report has attempted to provide the steps for designing the impulse ground penetrating RADAR (GPR) as well as provides the value of crucial parameters required in the design process of commercial GPR systems.
EN
There is a very strong link between the behavior of ground penetrating radar (GPR) wave propagation in zinc-contaminated soil and the dielectric properties of soil. This relationship can be of signifcant use in the practices of quick detecting the degree of pollution in zinc-contaminated soil. In this research, measurements were conducted on the zinc-contaminated soil samples with diferent soil index properties (i.e., zinc ion concentration, wet density and moisture content). The radar refection wave data of the common midpoint and common-ofset sounding mode were obtained by using the 600 MHz antenna, and the relative permittivity was measured using the vector network analyzer. The attribute analysis of radar refection wave shows that the wave velocity is afected by wet density and moisture content, but independent of zinc ion concentration. Both the amplitude and the peak frequency decrease with the increase in zinc ion concentration, wet density and moisture content. For the soil dielectric properties, the metal ions can change the conductivity of solution in soil, afecting the imaginary part of relative permittivity, but with little efect on the real part. The positive correlations between the relative permittivity with density and moisture content are caused by the variation of three-phase composition of soil. Besides, the measured soil dielectric properties and the radar refected wave attributes confrm each other, which can well explain the change rules of electromagnetic wave velocity, amplitude and central frequency. The presented results can increase understanding and confdence on GPR for quantitative monitoring and detecting of zinc-contaminated soil.
PL
W artykule przedstawiono relacje między stopniem zagęszczenia gruntu określonym penetrometrem stożkowym, przewodnością elektryczną gruntu na wybranych głębokościach jego profilu określoną konduktometrem oraz echogramem wykonanym georadarem. Badania przeprowadzono w warunkach rzeczywistych a do zagęszczania gruntu wykorzystano ciągnik rolniczy wyposażony w standardowe opony. Zidentyfikowano istotną zbieżność wyników pomiarów dla wszystkich metod pomiarowych, która pozwala stosować je wymiennie do identyfikacji nadmiernego zagęszczenia gruntu np. śladów przejazdu maszyn a także innych anomalii w zagęszczeniu gruntu pod warunkiem istnienia wyrównanych parametrów wilgotnościowych mierzonego ośrodka.
EN
The article presents the relationship between the degree of soil compaction determined by a cone penetrometer and soil electrical conductivity at selected depths of its profile determined by a conductometer and a GPR echogram. The tests were carried out in real conditions and an agricultural tractor equipped with standard tires was used for soil compaction. Significant convergence of measurement results was identified for all measurement methods, which allows them to be used interchangeably to identify excessive soil compaction, e.g. machine tracks, as well as other anomalies in soil compaction, provided that the humidity parameters of the measured medium are equal.
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
This paper presents a suggested approach for forensic investigation of bridge decks in which Ground penetrating radar (GPR) consisting of two antennas is used to assess the current conditions. The methodology was tested on a bridge deck in central Sicily. The acquired data were analyzed for identifying the asphalt overlay thickness, concrete cover depth and deck thickness and location of the rebar reinforcement. In the proposed approach for assessing bridge deck conditions the GPR survey was complemented with (i) a site investigation on layer thicknesses for calibration/verification purposes of the GPR response and (ii) a Terrestrial Laser Scanning system (TLS) to verify the bridge design slab curvature. The study shows that this methodology has significant merits on accurately assessing such bridge deck components when bridge design records are non-existing, and by using non-invasive methods such as laser scanning and GPR. The great advantage provided by the TLS technique is the possibility to obtain a 3D output model of the scanned element with the accuracy of the best topographic instruments in order to complement GPR data surveys for bridge inspection.
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).
EN
Intensified investment processes in construction have resulted in increased interest in the methods of efficient detection, verification and location of underground utility networks. In addition to the well-known pipe and cable locating equipment, which has increased its efficiency and reliability through the development of technologies, GPRs are becoming more and more popular. This publication presents the results of the experimental research carried out with the use of GPRs manufactured by two different companies as well as the results of the verification of underground utilities in real conditions. The GPRs have worked in the mode of the real-time location of their own position using the GNSS system or robotic total stations. The GPR (Ground Penetrating Radar) surveys performed on a test field, consisting of 9 pipes with a known position, were aimed at assessing the accuracy of their identification on echograms. The utility line location errors were determined using three different combinations between the GPR and the locating instrument. It allowed the evaluation of the possibility of using these solutions for detection, verification and location of underground utility networks in the light of the Polish legal regulations and the British specification PAS 128. The verification in real conditions was carried out in a typical urban space, characterised by an intense occurrence of underground utilities, that is, sewage systems, gas pipelines and power cables. It was based on the GESUT database captured from the county geodetic and cartographic documentation centre. The results of the visual analysis of the materials captured with the help of two measurement systems were described in detail, however, the verification was carried out only for one set of data. The authors have presented the procedure of processing echograms and detecting the location of pipeline axes based on their vectorisation. The authors of this research paper have performed a numerical analysis of the compliance of the profiles of utility lines with the information from the base map for two variants of the GPR data integration with the coordinates. The authors of this research paper have also presented an alternative concept of capturing the profile of a utility line in the field based on the processing of GPR data in 3D – the so-called C-scan. The conclusions summarise the possible factors affecting the surveying results and the methods of eliminating sources of errors, both for the GPR and geodetic data.
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.
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