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D. Malfitana G. Leucci A. Mazzaglia G. Cacciaguerra L. De Giorgi S. Barone G. Fragalà P. D. Pavone S. Russo 《Surveys in Geophysics》2018,39(6):1219-1238
Within the extraordinary archaeological site of Pompeii, the Porta Nocera necropolis represents one of the most important sites with funerary monuments, burials and associated graves. The inherent informative potential of the archaeological/monumental heritage present in the Porta Nocera necropolis poses notable problems for the conservation and restoration of the structures and surfaces of the funerary monuments. Brought to light at different times during the second half of last century, they show signs of degradation caused by atmospheric agents and the rising level of the water table, which threatens the foundations. Other important monuments could be still buried. In order to verify both the state of preservation of the foundations of funerary buildings, the presence of still active causes of deterioration and the probable presence of other buried archaeological structures, integrated geophysical surveys, with ground penetrating radar (GPR), passive (Self Potential—SP) and active electrical resistivity tomography (ERT), were undertaken. Furthermore a three-dimensional model of the entire necropolis was created. This involved the creation of a specific survey methodology, combining laser scanning with ortho-photogrammetry using shots taken on the ground and from the air by the use of a drone. The integration of the acquired data allows us to plan future interventions of restoration. 相似文献
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高分辨率探地雷达及实验研究 总被引：1，自引：0，他引：1
本文作者开发基于E5071B型矢量网络分析仪(VNA)的高分辨率探地雷达系统(LANRCS—GPR),该系统立足于频率域探地雷达系统的宽频带和适应性强的优点之上,充分发挥了矢量网络分析仪具有的超宽带、高精度测量等特性。该系统采用LAN方式进行系统联机控制方式,使系统组建成本低廉、易于扩展:本系统采用了计算效率高的F-K偏移方法作为实时成像方法。系统测试实验表明,该系统具有很高的探测分辨率,探测精度高,信号信噪比高,系统动态范围大,而且系统的操作灵活可靠,适应范围广,系统功能可扩展性强。该系统的研究开发为将来成品频域探地雷达系统的研发提供了理论、实验基础,同时也为电磁波传播研究及电磁探测研究搭建了一个采集数据精度高、信息量大、适应范围广、操作方便的实验平台。 相似文献
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机载探地雷达可能解决危险环境或广域条件下的近地表探测问题,用于解决环境、生态或军事方面的问题.然而由于种种原因,该技术的发展却显得比较慢.为了推进该技术的发展,本文介绍了目前世界范围内机载探地雷达的进展,并利用时间域有限差分法对一些典型模型进行数值模拟,并用特定的偏移成像方法对模拟结果进行成像.目前存在的机载探地雷达主要有三种类型:第一种为将常规探地雷达天线悬挂在直升飞机上,第二种为针对机载探地雷达开发的雷达系统,第三种为具有探地能力的合成孔径雷达.数值模拟结果表明,不管是水平地面的情况下,还是起伏界面的情况下,机载探地雷达都能清楚探测一定深度范围内的地下目标.可见,机载探地雷达是存满希望的一种方法. 相似文献
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沥青混凝土是由骨料、沥青胶浆、空气按照一定的体积百分比混合而成的多相非匀质混合物,其骨料、沥青胶浆和空气的体积不等、形状各异、介电特性不同、空间位置随机分布,具有明显的多相、离散、随机介质特征.本文基于随机介质模型理论,(1)测量与统计了介电常数在典型沥青混凝土芯样空间上的随机分布统计特征;(2)估算了沥青混凝土介质的自相关函数及其特征参数(自相关长度、自相关角度等),确定其随机介质类型;(3)提出了量化约束下的多相离散随机介质建模算法,以混合型椭圆自相关函数为基础,构建了不同粗糙度因子的多相离散随机介质模型;(4)构建了不同空隙率的多相离散随机介质模型,正演模拟与对比分析了探地雷达波在均匀介质、连续型随机介质和多相离散随机介质中的传播特征.结果表明:多相离散随机介质模型不仅描述了沥青混凝土的多相、离散与空间随机分布统计特征,而且进一步描述了其各组成物质体积百分比,能更全面、准确地描述沥青混凝土的介质特征,同时也为描述其他类似材料或介质提供了新的方法和途径;在多相离散随机介质模型中,探地雷达波散射强烈,随机、无序传播的散射波相互叠加干涉,形成了明显的随机扰动和"噪声",致使异常体反射波扭曲变形、不连续,降低了探地雷达回波的信噪比和分辨率.研究探地雷达波的随机扰动特征与多相离散随机介质模型参数之间的关系,将为定量评价多相离散随机介质的属性参数提供参考和帮助. 相似文献
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Paulo Roberto Antunes Aranha Cristina Helena Ribeiro Rocha Augustin Frederico Garcia Sobreira 《Journal of Applied Geophysics》2002,49(4)
Ground penetrating radar (GPR) has been used as a tool to access information about ground subsurface features. Such information is very important for different types of studies, varying from those related to archeological research to those studying geological elements of bedrock. More recently, however, GPR has been increasingly applied to environmental studies, especially for soil research. This paper presents the results of an application of GPR for the study of weathered profiles. GPR was used to discover the degree of trustworthiness of the information on the ground subsurface through the interpretation of the results of the radar sections as well as the data collected from boreholes, which reached until 21 m. The results show a relatively high degree of details obtained by GPR, indicating the possibility of speeding up ground subsurface surveys related to geomorphological, geological, and pedological studies. 相似文献
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Geophysical surveys have been carried out in two fjord delta aquifers in western Norway. Geophysical methods comprised ground penetrating radar (GPR), shallow reflection seismic and resistivity measurements. The purpose of the investigations was to evaluate hydrogeological properties of the fjord delta aquifers with emphasis on the possibilities of abstracting saline groundwater for use in fish farming. At Sunndalsøra, reflection seismic was helpful in the mapping of the base of the aquifer. Resistivity profiles revealed both the spatial and seasonal variability of seawater intrusion. Penetration depths of ground penetrating radar (GPR-D) revealed the spatial variation of the boundary of the transition zone between saline and fresh groundwater. Maps of GPR-D can be used to indicate direction and magnitude of mean hydraulic gradients and thus to locate optimal sites for both fresh and saline groundwater abstraction.In fjord delta aquifers, both rivers and abandoned river channels constitute important groundwater divides. Optimal locations for saline groundwater abstraction wells are in areas separated from the rivers by abandoned river channels. In areas between the rivers and the abandoned river channels, groundwater abstraction will result in decreasing salinity of the water. 相似文献
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Jose L. Bermejo William A. Sauck Estella A. Atekwana 《Ground Water Monitoring & Remediation》1997,17(4):131-137
Alight nonaqueous phase liquid (LNAPL) ground water contaminant plume has been discovered by purely geophysical means at the former Wurtsmith Air Force Base (AFB) near Oscoda, Michigan. It is located near another plume called FT-02, which is a well-studied area undergoing natural bioremediation. The plume was discovered by ground penetrating radar (GPR) profiling while extending a long line from FT-02 to establish background variability around that plume. The new plume was apparent because of a high-conductivity "shadow' or GPR reflection attenuation observed below the conductive zone at the top of the aquifer, identical to the pattern observed at the FT-02 plume. Further GPR surveys were conducted by students of a Western Michigan University geophysics field course to outline the proximal part of the plume. The GPR survey was supplemented by an electromagnetic induction (EM) survey which showed a group of four cables crossing the area. Finally, a magnetometer survey was conducted to search for any buried steel objects which might have been missed by the EM survey. The results of the three geophysical surveys were then used by students of a University of Michigan field course to guide subsurface soil and fluid sampling, which verified the presence of residual LNAPL product and ground water with conductivities 2.5 to 3.3 times above background. The plume source is in the vicinity of a vaulted underground storage tank (UST) formerly used for the collection of waste solvents and fuels for subsequent use in the fire training exercises at FT-02. This newly discovered LNAPL plume, along with other "mature' plumes, fits the electrical model which predicts conductive ground water below the decomposing but electrically resistive LNAPLs. Finally, this is a fine example of the cooperative use of a dedicated research site for training by students of two different universities. 相似文献
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Gary R. Olhoeft 《Journal of Applied Geophysics》2000,43(2-4)
Ground penetrating radar data is not always easy to acquire, and sometimes the acquisition may be constrained by equipment availability, weather, legal or logistical constraints, safety or access considerations. Examples of these include archaeological or geotechnical sites about to be excavated, contaminated lands undergoing remediation, hazardous areas such as unexploded ordnance lands or active volcanoes, and difficult to visit locations such as Antarctica or the surface of Mars. These situations may result in only one chance at acquiring data. Thus, the data need to be acquired, processed and modeled with the aim of maximizing the information return for the time, cost and hazard risked. This process begins by properly setting up the survey with the expectation of the site conditions but allowing for flexibility and serendipity in the unknown. Not only are radar data acquired, but also calibration, orientation, location and other required parameters describing the equipment and survey are recorded. All of these parameters are used in the processing and modeling of the data. The final results will be not just a radar image as a pseudo-cross-section, but a corrected geometric cross-section, interpreted electrical and magnetic properties of the ground, location, orientation, size and shape of subsurface objects, and composition of the ground and objects as inferred density, porosity, fluid saturation, and other relevant material occurrence properties. 相似文献
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Englacial and subglacial water flow at Skálafellsjökull,Iceland derived from ground penetrating radar,in situ Glacsweb probe and borehole water level measurements 
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下载免费PDF全文 We reconstruct englacial and subglacial drainage at Skálafellsjökull, Iceland, using ground penetrating radar (GPR) common offset surveys, borehole studies and Glacsweb probe data. We find that englacial water is not stored within the glacier (water content ~0–0.3%). Instead, the glacier is mostly impermeable and meltwater is able to pass quickly through the main body of the glacier via crevasses and moulins. Once at the glacier bed, water is stored within a thin (1 m) layer of debris‐rich basal ice (2% water content) and the till. The hydraulic potential mapped across the survey area indicates that when water pressures are high (most of the year), water flows parallel to the margin, and emerges 3 km down glacier at an outlet tongue. GPR data indicates that these flow pathways may have formed a series of braided channels. We show that this glacier has a very low water‐storage capacity, but an efficient englacial drainage network for transferring water to the glacier bed and, therefore, it has the potential to respond rapidly to changes in melt‐water inputs. © 2015 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
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《Journal of Applied Geophysics》2011,75(4):175-184
Ballast fouling is created by the breakdown of aggregates or outside contamination by coal dust from coal trains, or from soil intrusion beneath rail track. Due to ballast fouling, the conditions of rail track can be deteriorated considerably depending on the type of fouling material and the degree of fouling. So far there is no comprehensive guideline available to identify the critical degree of fouling for different types of fouling materials. This paper presents the identification of degree of fouling and types of fouling using non-destructive testing, namely seismic surface-wave and ground penetrating radar (GPR) survey. To understand this, a model rail track with different degree of fouling has been constructed in Civil engineering laboratory, University of Wollongong, Australia. Shear wave velocity obtained from seismic survey has been employed to identify the degree of fouling and types of fouling material. It is found that shear wave velocity of fouled ballast increases initially, reaches optimum fouling point (OFP), and decreases when the fouling increases. The degree of fouling corresponding after which the shear wave velocity of fouled ballast will be smaller than that of clean ballast is called the critical fouling point (CFP). Ground penetrating radar with four different ground coupled antennas (500 MHz, 800 MHz, 1.6 GHz and 2.3 GHz) was also used to identify the ballast fouling condition. It is found that the 800 MHz ground coupled antenna gives a better signal in assessing the ballast fouling condition. Seismic survey is relatively slow when compared to GPR survey however it gives quantifiable results. In contrast, GPR survey is faster and better in estimating the depth of fouling. 相似文献
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Automatic extraction of geometrical characteristics hidden in ground‐penetrating radar sectional images using simultaneous perturbation artificial bee colony algorithm 下载免费PDF全文
下载免费PDF全文 Ground‐penetrating radar is one of the most effective methods of detecting shallow buried objects. Ground‐penetrating radar radargram is a vertical map of the radar pulse reflections that returns from subsurface objects, and in the case of cylindrical objects, it would be a hyperbola. In order to get clear and accurate information on the presence, location, and geometry of the buried objects, the radargrams need to be interpreted. Interpretation of the results is a time‐consuming task and needs an expert with vast knowledge. Development of an automatic interpretation method of B‐scan ground‐penetrating radar images would be an effective and efficient solution to this problem. A novel automatic interpretation method of ground‐penetrating radar images, based on simultaneous perturbation artificial bee colony algorithm using tournament selection strategy, simultaneous perturbation stochastic approximation method, and new search equations, is introduced in this paper. The proposed algorithm is used to extract geometrical parameters, i.e. depth, location, and radius, of buried cylindrical objects in order to assess its accuracy. Synthetic data, simulated using GprMax2D forward modelling program, and real data, surveyed in the campus of Isfahan University of Technology, are used in the assessment. The performance of the proposed method in detecting synthetic hyperbolas is compared with that of the original artificial bee colony algorithm, genetic algorithm, and modified Hough transform. The results show superiority of the proposed algorithm, in detecting synthetic hyperbolas. Furthermore, the performance of the proposed method in estimating depth and radius of pipes in real ground‐penetrating radar images is compared with that of the modified Hough transform. The results indicate higher accuracy of the proposed method in estimating geometrical parameters of the buried cylindrical objects. 相似文献
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Mapping of glaciotectonic deformation in an ice marginal environment with ground penetrating radar 总被引：1，自引：0，他引：1
A series of closely spaced parallel ground penetrating radar (GPR) profiles of glaciotectonic deformed glacio-fluvial sediments have been obtained in an ice marginal environment in Northwest Zealand, Denmark. The radar profiles can be differentiated into several radar facies with distinct reflection characteristics. The lithology and depositional environment of the radar facies is interpreted by correlation with information from profiles in gravel pits, geological maps and drill hole data. The radar facies include glaciotectonically disturbed glacio-fluvial sediments, sediments deposited penecontemporaneously with the deformations and sediments deposited post-tectonically. Several thrust planes with dip angles between 25° and 30° as well as major folds and minor faults have been interpreted from the GPR data. The deformation style of the deformed glacio-fluvial sediments is a thin-skinned pro-glacial thrust complex, with associated folding. The deformations have resulted in the present ridge morphology seen in the rim of the composite ridge. Syn- and post-tectonic sediments are deposited on top and in front of the deformed sediments, smoothing the ridge relief created by the thin-skinned thrust complex. A structural geological map constructed from the ground penetrating radar data reveals the extension of the individual radar facies in the thrust complex. Tectonic features such as thrust planes and folds can be followed throughout the mapped area. 相似文献
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The full solution for the wavenumber equation in electromagnetic (EM) theory is available, but not routinely used when processing ground penetrating radar (GPR), and electromagnetic induction (EMI) data. The wavenumber approach is important as it is used for the development of concepts such as skin depth and phase velocity, as well as being the basis for more complete interpretation of EM data sets. Approximations that make the solution simpler are common, and sufficiently accurate, provided that the underlying assumptions are not grossly violated. With the advent of lower-frequency GPR systems (25 MHz and below) and higher-frequency EMI systems (greater than 100 kHz) such approximations need to be re-examined. This paper reviews the full wavenumber expression and then compares phase velocity and skin depth equations based on approximations with the equations for the same parameter based on the full solution. This comparison allows the conditions under which the assumptions are valid to be refined. In this paper it is shown that for GPR surveys conducted under transition band conditions, the error in phase velocity estimates based on low-loss assumptions may be 40%. Similarly, for EMI surveys the skin depth estimation errors may be more than 30% when the equation based on quasi-static assumptions is used instead of the full solution. 相似文献
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在分析核电站防波堤常见安全隐患及其产生机理的基础上,采用目前较为先进的探地雷达检测技术,对实际的堤防进行模拟检测,探究探地雷达检测防波堤的适用性和准确性.分析表明,探地雷达作为一种无损检测方法对防波堤的检测是可行的,且检测准确度满足实际工程的要求,可以用于核电站海堤的日常安全检测和维修加固后的成果检验. 相似文献
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道路塌陷空洞一直是威胁交通安全运行的重要隐患,对道路塌陷空洞的探测方法进行研究具有重大的现实意义。研究工作通过实例探讨三维探地雷达（GPR）对道路塌陷区进行探测的方法技术及其应用效果。为查明道路塌陷空洞的空间分布特征,在塌陷区布设了共23条测线,1.0 m×0.5 m的三维测网并进行数据采集;通过对雷达数据进行处理,获得不同测线、不同方向的三维雷达剖面。结合地质情况对上述图件进行综合分析与解释,准确地查明塌陷空洞的位置、埋深及发育程度;经开挖验证,解译结果可靠。工程实践表明,三维探地雷达技术可以快速、高效地应用于道路塌陷探测中,其探测结果可为塌陷区后续施工以及安全防治提供参考。 相似文献
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This study demonstrates the potential value of a combined unmanned aerial vehicle (UAV) Photogrammetry and ground penetrating radar (GPR) approach to map snow water equivalent (SWE) over large scales. SWE estimation requires two different physical parameters (snow depth and density), which are currently difficult to measure with the spatial and temporal resolution desired for basin-wide studies. UAV photogrammetry can provide very high-resolution spatially continuous snow depths (SD) at the basin scale, but does not measure snow densities. GPR allows nondestructive quantitative snow investigation if the radar velocity is known. Using photogrammetric snow depths and GPR two-way travel times (TWT) of reflections at the snow-ground interface, radar velocities in snowpack can be determined. Snow density (RSN) is then estimated from the radar propagation velocity (which is related to electrical permittivity of snow) via empirical formulas. A Phantom-4 Pro UAV and a MALA GX450 HDR model GPR mounted on a ski mobile were used to determine snow parameters. A snow-free digital surface model (DSM) was obtained from the photogrammetric survey conducted in September 2017. Then, another survey in synchronization with a GPR survey was conducted in February 2019 whilst the snowpack was approximately at its maximum thickness. Spatially continuous snow depths were calculated by subtracting the snow-free DSM from the snow-covered DSM. Radar velocities in the snowpack along GPR survey lines were computed by using UAV-based snow depths and GPR reflections to obtain snow densities and SWEs. The root mean square error of the obtained SWEs (384 mm average) is 63 mm, indicating good agreement with independent SWE observations and the error lies within acceptable uncertainty limits. 相似文献
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Maurizio Lazzari Lara De Giorgi Giuseppe Ceraudo Raffaele Persico 《Surveys in Geophysics》2018,39(6):1167-1180
In this paper, the results of a ground penetrating radar (GPR) prospecting survey performed in the Roman archaeological site of Aquinum are shown. The prospecting was performed in two distinct areas. The first one was close to the remains of the ancient thermal baths, where a public project intends to build a car park. The second area is close to an apsidal Roman building, and it was of interest to establish whether, and possibly up to what extent, the remains of this partially revealed structure continue, or maybe whether meaningful further structures are present. 相似文献