Analytical Models and Laboratory Measurements to Explore the Potential of GPR for Quality Control of Marble Block Repair through Resin Injections

Izadi-Yazdanabadi, M.; Hojat, A.; Zanzi, Luigi; Nasab, Saeed Karimi; Arosio, Diego

doi:10.3390/app12030987

Cited by 2 publications

(6 citation statements)

References 43 publications

(55 reference statements)

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“…However, time-lapse measurements should be properly executed and analyzed to appreciate the amplitude decrease resulting from injection. The amplitude is expected to be reduced by about 33% or even more [21]; the precise value depends on the permittivity values of the resin and the marble.…”

Section: Methodsmentioning

confidence: 99%

“…Numerical simulations and analytical models can predict the difference between the air-filled and resin-filled fractures [18,21]. Figure 11 indicates the predicted theoretical difference between the air-filled and the resin-filled fractures obtained by tuning the analytical models to the actual marble velocity measured on the Carrara blocks (10.8 cm/ns).…”

Section: Laboratory Measurementsmentioning

confidence: 99%

“…In recent years, an increasing interest emerged to explore the efficiency of the GPR method to diagnose fractures and determine their aperture and filling material. This is still an interesting research issue with ongoing studies [10,[18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

“…The ground-penetrating radar (GPR) method is a totally non-destructive sensing technique capable of providing high-resolution images for a variety of engineering applications [13][14][15][16][17]. The GPR method has proved its ability as a valuable geophysical technique to enter the quarrying and construction industries to map the fractures at different stages: during exploration and extraction in quarries to reduce the production costs and wastes [6,7,[10][11][12][18][19][20], and for post-production demands to repair and restore the stones [21]. From various research studies that use the GPR method to study rock fractures, we can mention the theoretical models and laboratory experiments used to characterize rock discontinuities [18][19][20][21][22][23][24][25][26], in situ GPR surveys to detect fractures at different zones of quarries or in historical buildings [7,10,12,15,22,[27][28][29][30], and 3D GPR acquisitions for 3D reconstruction of the fractures and other features [11,12,[31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…When the layer becomes thicker, the magnitude of the reflection coefficient progressively grows with a decreasing gradient until it arrives at its maximum value in correspondence of a fracture aperture equal to a quarter of the wavelength. As a result, the reflection coefficient variations can be used for characterizing the thin bed properties [18,[35][36][37][38][39], e.g., to study thickness variations or to distinguish different filling materials [18,21].…”

Section: Introductionmentioning

confidence: 99%

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Time-Lapse GPR Measurements to Monitor Resin Injection in Fractures of Marble Blocks

Zanzi,

Izadi-Yazdanabadi,

Karimi-Nasab

et al. 2023

Sensors

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The objective of this study is to test the feasibility of time-lapse GPR measurements for the quality control of repairing operations (i.e., injections) on marble blocks. For the experimental activities, we used one of the preferred repairing fillers (epoxy resin) and some blocks from one of the world’s most famous marble production area (Carrara quarries in Italy). The selected blocks were paired in a laboratory by overlapping one over the other after inserting very thin spacers in order to simulate air-filled fractures. Fractures were investigated with a 3 GHz ground-penetrating radar (GPR) before and after the resin injections to measure the amplitude reduction expected when the resin substitutes the air. The results were compared with theoretical predictions based on the reflection coefficient predicted according to the thin bed theory. A field test was also performed on a naturally fractured marble block selected along the Carrara shore. Both laboratory and field tests validate the GPR as an effective tool for the quality control of resin injections, provided that measurements include proper calibration tests to control the amplitude instabilities and drift effects of the GPR equipment. The method is accurate enough to distinguish the unfilled fractures from the partially filled fractures and from the totally filled fractures. An automatic algorithm was developed and successfully tested for the rapid quantitative analysis of the time-lapse GPR profiles collected before and after the injections. The whole procedure is mature enough to be proposed to the marble industry to improve the effectiveness of repair interventions and to reduce the waste of natural stone reserves.

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Section: Methodsmentioning

confidence: 99%

Section: Laboratory Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Time-Lapse GPR Measurements to Monitor Resin Injection in Fractures of Marble Blocks

Zanzi,

Izadi-Yazdanabadi,

Karimi-Nasab

et al. 2023

Sensors

Self Cite

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Laboratory Tests and Field Surveys to Explore the Optimum Frequency for GPR Surveys in Detecting Qanats

Hojat

Ranjbar

Nasab

et al. 2023

Pure Appl. Geophys.

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In this paper, we discuss the results of laboratory tests and field surveys using ground penetrating radar (GPR) method to detect qanats at the main campus of Shahid Bahonar University of Kerman (SBUK), Iran. The main purpose of laboratory experiments was to explore the optimum frequency of GPR surveys to detect qanats for the subsoil in the study site. We performed a variety of laboratory tests with a 3 GHz antenna to detect qanats (simulated using dielectric empty targets) hosted by sand with volumetric water content (VWC) values in the range 1.5–8%. The depth to each target was progressively increased until either approaching the edges of the sandbox or modelling a qanat depth for which GPR data could not detect the target anymore. The scaling factors were calculated for each test to estimate the maximum depth of detecting qanats as a function of the scaled GPR frequency. The results showed that in areas where the subsoil is dominated by sand, medium-frequency GPR antennas can penetrate to depths of a few tens of meters, but the penetration depth considerably decreases when the soil moisture and/or clay content of the medium increase. Based on the results of laboratory simulations, qanats are detectable at a maximum normalized depth of about 15–17 times of the wavelengths in very dry sands with VWC less than 5% while the detectable range rapidly drops down to less than 3 or 4 times of the wavelengths in more humid sands with VWC of about 8%. We also discuss the results of a few field GPR surveys that were measured using antennas with the 50 MHz and the 250 MHz frequencies in the northwestern part of the study area. The processed GPR images could detect a qanat in the position compatible with the results of previous remote sensing studies performed in the area. The depth to the detected qanat is 13.5 m, which is a little bit beyond the maximum limit predicted by the laboratory tests.

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Analytical Models and Laboratory Measurements to Explore the Potential of GPR for Quality Control of Marble Block Repair through Resin Injections

Cited by 2 publications

References 43 publications

Time-Lapse GPR Measurements to Monitor Resin Injection in Fractures of Marble Blocks

Time-Lapse GPR Measurements to Monitor Resin Injection in Fractures of Marble Blocks

Laboratory Tests and Field Surveys to Explore the Optimum Frequency for GPR Surveys in Detecting Qanats

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