Effect of the height of the observation line on the the diffraction curve in GPR prospecting

Persico, Raffaele; Leucci, Giovanni; Matera, Loredana; Giorgi, Lara De; Soldovieri, Francesco; Cataldo, Andrea; Cannazza, Giuseppe; Benedetto, Egidio De

doi:10.3997/1873-0604.2014042

Cited by 33 publications

(11 citation statements)

References 24 publications

(23 reference statements)

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“…The electromagnetic (EM) wave velocity was determined from the reflection profiles acquired in continuous mode, using the characteristic hyperbolic shape of the reflection from a point source [36][37][38][39].…”

Section: Geophysical Prospecting: Gprmentioning

confidence: 99%

Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)

et al. 2021

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The Wied il-Mielaħ Window (Gozo–Malta) is a limestone natural arch on the north-western coast of the island of Gozo in Malta. It is located at the end of the Wied il-Mielaħ valley north of the village of Għarb. This natural arch is less well known than the Azure Window, which collapsed in March 2017 following a heavy storm, but notwithstanding, it is an imposing and important natural monument too. In the past, the Wied il-Mielah valley was responsible for discharging wastewater from the surrounding localities to the Mediterranean directly at the Wied il-Mielah Window. The sewage flag was often clearly visible underneath the archway into the open sea. The natural features of the arch provide an outstanding touristic attraction. To avoid what happened to the Azure Window, a methodology for the evaluation of the collapse hazard, combining passive seismic, ground penetrating radar (GPR), geological/geomorphological surveys and mine engineering methods, is here proposed. In this study, a methodological approach was applied, based on the following: (i) passive seismic method to study the physical–mechanical characteristics of the rock mass that constitutes the window; (ii) GPR method in order to demonstrate the conservation state (i.e., the intensity of fracturing); (iii) geological/geomorphological surveys in order to obtain a crack pattern; and (iv) scaled span empirical analysis in order to evaluate the stability of the arch. The calculation of the safety factor, with a static method, gave a value equal to 3.75 with a probability of collapse of the marine arch within 50 and 100 years.

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Section: Geophysical Prospecting: Gprmentioning

confidence: 99%

Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)

et al. 2021

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“…However, this is a complex phenomenon and customarily is not accounted for by commercial codes. In particular, even the evaluation of the propagation velocity in the deeper layers should account for the modification of the diffraction hyperbolas due to the refraction of the waves [5], which customarily is not possible with a commercial processing software. We will neglect these effects, as often done in the praxis.…”

Section: Combination Of Migrations and Joined Time-depth Conversionmentioning

confidence: 99%

“…The analysis of concrete layers is a classical GPR application where, in particular, reinforcement rebars are looked for and the status of the concrete (moisture, moisture gradient, fractures, salt content) is of interest for maintenance purposes and analyses of possible damages or even possible dangerous situations [1][2][3]. In many cases, the presence of reinforcing bars embedded in the concrete can provide meaningful help in inferring the status and the "health" of the embedding material by means of their diffraction hyperbolas [4][5][6][7]. The diffraction hyperbolas can provide direct information about the dielectric permittivity of the propagation medium crossed by the electromagnetic waves; they can also provide qualitative information about the losses in the concrete if some hyperbolas appear weaker than the others at parity of time depth.…”

Section: Introductionmentioning

confidence: 99%

Combined Migrations and Time-Depth Conversions in GPR Prospecting: Application to Reinforced Concrete

Persico

Morelli²

2020

Remote Sensing

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In this paper, we propose the combination of different migration results achieved on the same data in order to account for different values of the propagation velocities of the electromagnetic waves within the considered Ground Penetrating Radar (GPR) profile. These different values can be the result of a variable lithological composition or (more probably for short Bscans) the results of different moisture levels, or both. Here, we separately consider the two cases of horizontal or vertical variability of the propagation velocity with a transition zone between two zones with constant propagation velocity. Moreover, we also propose a time-depth conversion accounting for these different values of the propagation velocity along the considered GPR Bscan. The method is applied to real data gathered in the field with regard to a concrete coverage containing liner layers.

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“…This is a very common method of velocity estimation and it is based on the phenomenon that a small object reflects EM-waves in almost every direction. In the data set, several hyperbolic reflections caused by objects of small dimensions such as node (Figure 4) are present, enabling EM wave velocity analysis to be performed [30,31,32]. Figure 5 shows an example of velocity analysis performed on the data set.…”

Section: Volumetric Water Content Analysismentioning

confidence: 99%

Integrated geophysical and mechanical study on the wooden structures of the ceiling of the Church of Beata Vergine Maria Assunta in Cielo

Giorgi¹,

Leucci²,

Melica³

2018

ACTA IMEKO

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Non-destructive testing by mean of ground penetrating radar were performed on the wooden elements constituting the roofing of the Cathedral of Foggia. These measurements were related to the restoration work of the roof. Measurements campaign aimed at the assessment of the conservation status of the wooden elements of the all major and secondary elements of the truss of the nave, as well as on those main of the dome and the apse. Results show various abnormalities which correspond to nodes and/or slots. The presence of the nodes allow a rapid and accurate analysis of the electromagnetic waves velocity and the volumetric water content.

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Effect of the height of the observation line on the the diffraction curve in GPR prospecting

Cited by 33 publications

References 24 publications

Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)

Stability Assessment and Geomorphological Evolution of Sea Natural Arches by Geophysical Measurement: The Case Study of Wied Il-Mielah Window (Gozo, Malta)

Combined Migrations and Time-Depth Conversions in GPR Prospecting: Application to Reinforced Concrete

Integrated geophysical and mechanical study on the wooden structures of the ceiling of the Church of Beata Vergine Maria Assunta in Cielo

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