scholarly journals Application of Ground Penetrating Radar to Estimate Subgrade Soil Density

2020 ◽  
Vol 5 (2) ◽  
pp. 12 ◽  
Author(s):  
Ahmad Abdelmawla ◽  
S. Sonny Kim
Keyword(s):  
Ground Penetrating Radar ◽  
Exponential Model ◽  
Solid Particles ◽  
Road Maintenance ◽  
Time Saving ◽  
Moving Vehicle ◽  
Subgrade Soils ◽  
Density Prediction ◽  
Pavement Deterioration ◽  
Ground Penetrating

Ground penetrating radar (GPR) technology has been widely used in pavement assessment over the last decade. Assessing the subgrade condition and monitoring its temporal variation provide valuable information regarding changes associated with pavement deterioration, allowing for the beneficial prediction of future road maintenance. This paper presents a method to estimate the density and water content of prepared subgrade soils of highly plastic silt using a 2 GHz GPR scan system and a simple exponential model. A bulk density prediction model was developed based on electromagnetic mixing theory to back calculate subgrade soils density. The model developed determines the soil’s dielectric constant, considering dielectric and volumetric properties of the three major components of soil: air, water, and solid particles. A series of laboratory tests was conducted on six (6) soil samples at various density levels to validate the newly developed model. For validation purposes, sand cone and dynamic cone penetration (DCP) tests were performed and compared with the estimated soils strength from GPR data. The results show that the prediction of soils density and stiffness using nondestructive technology helps efficiently forecast not only pavement deterioration, but potential risks to the subsurface pavement structure with all the advances of time saving using air coupled GPR antenna mounted on a moving vehicle.

Using Ground-Penetrating Radar and Dielectric Probe Measurements in Pavement Density Quality Control

1997 ◽  
Vol 1575 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Timo Saarenketo
Keyword(s):  
Ground Penetrating Radar ◽  
Structural Damage ◽  
Low Cost ◽  
Field Tests ◽  
Dielectric Surface ◽  
Void Content ◽  
Moving Vehicle ◽  
Surface Probe ◽  
Ground Penetrating ◽  
Probe Measurements

Ground-penetrating radar and capacitance-based dielectric surface probe measurements are used to measure fluctuations in voids, bitumen content, or both, in newly asphalted pavements without causing structural damage. Both methods rely on the compaction of asphalt to reduce the proportion of low-dielectricity air in the material, which increases the volumetric proportions of high-dielectricity bitumen and rock and thus results in higher asphalt dielectricity values. Ground-penetrating radar enables pavement thickness to be measured rapidly from a moving vehicle and information on variations in pavement voids content to be collected simultaneously on the basis of dielectricity fluctuations. The results can be calibrated against real void content by material sampling or by comparison of dielectric value with voids content values determined beforehand for the same material under laboratory conditions. This means that the subcontractor can be informed quickly of any values that exceed or fall below the norms and can take immediate steps to rectify such defects. Other advantages offered by the technique are the rapidity of the measurements and the immediate availability of the results. In addition, the one measurement provides simultaneous information on pavement and base thicknesses and the quality of the latter. The dielectric probe based on capacitance measurements lends itself to use in asphalt mass proportioning examinations performed at the laboratory stage, which enables the values to be used directly for monitoring in situ pavement compaction. The advantages of the dielectricity probe are rapidity of measurement, low-cost meters, and the avoidance of radiation. Thus far, the probe has been excessively sensitive to variations in the roughness of pavement surfaces. The theory behind these research methods is discussed, the methods are described, and the results of laboratory tests conducted at the Texas Transportation Institute in 1994–1995 and field tests performed in Finland in 1995 are presented.

Signal Stability and the Height-Correction Method for Ground-Penetrating Radar In Situ Asphalt Concrete Density Prediction

2021 ◽  
pp. 036119812110045
Author(s):  
Qingqing Cao ◽  
Imad L. Al-Qadi
Keyword(s):  
Adaptive Filter ◽  
Ground Penetrating Radar ◽  
Asphalt Concrete ◽  
Correction Method ◽  
Least Square ◽  
Least Mean Square ◽  
Signal Stability ◽  
Density Prediction ◽  
Ground Penetrating ◽  
The Impact

Ground-penetrating radar (GPR) has shown great potential for asphalt concrete density prediction used in quality control and quality assurance. One challenge of continuous GPR measurements is that the measured dielectric constant could be affected by signal stability and antenna height. This would jeopardize the accuracy of the asphalt concrete density prediction along the pavement. In this study, signal instability and shifting antenna height during continuous real-time GPR measurements were identified as main sources of error. After using a bandpass filter to preprocess the signal, a least-square adaptive filter, using gradient descent and least mean square methods, was developed to reconstruct the received signal to improve its stability. In addition, simulations were performed to evaluate the impact of geometric spreading caused by shifting antenna height during testing. A height correction was developed using a power model to correct the height-change impact. The proposed filter and height-correction method were assessed using static and dynamic tests. The least-square adaptive filter improved signal stability by 50% and the height-correction method removed the effect of shifting antenna height almost entirely.

scholarly journals Investigating the Causes of Roads Deterioration in the Form of Potholes using Non-Destructive Testing

2020 ◽  
Author(s):  
Muhammad Naveed ◽  
Kanishka S. Turrakheil ◽  
Fabio Tosti ◽  
Amir M. Alani
Keyword(s):  
Signal Processing ◽  
Ground Penetrating Radar ◽  
Radar Signal ◽  
Road Maintenance ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Material Condition ◽  
Local Roads ◽  
Ground Penetrating ◽  
Non Destructive

<p>Potholes are one of the public’s main local concerns as they cost a lot to the economy in terms of repair bills, delays while repairs are carried out and vehicle wear-and-tear. According to the Annual Local Authority Road Maintenance (ALARM) survey, eliminating the pothole backlog in England and Wales would cost £9.8bn and take a decade to complete despite increased local roads investment. The aim of this study is to research why potholes occur in the first place using non-destructive testing (NDT) and potential remedies in terms of the development of effective design and innovative materials to prevent their formation in future.</p><p>To investigate the causes of potholes formation, in-situ use of NDT methods such as ground-penetrating radar (GPR) has proven effectiveness as roads remain in continuous use. Analysis of GPR data can provide information on layer depths, material condition, moisture, voiding, reinforcement and location of other features [1, 2, 3].</p><p>Through our results, we will test two hypothesis; (i) shallow potholes are formed on loss of adhesion of the surface course, (ii) deep potholes are formed due to the loss of bearing capacity or settlement of the subgrade. Poor drainage in combination of heavy loads trigger shallow potholes while extreme wetting-drying cycles as a result of climate change decayed subgrade conditions of the pavement.</p><p>Results presented in this abstract are part of a PhD project funded by the University of West London.</p><p> </p><p><strong>References</strong></p><p>[1] Saarenketo, T. and T. Scullion (2000). Road evaluation with ground penetrating radar. Journal of Applied Geophysics (43): 119–138.</p><p>[2] Benedetto, A., Tosti, F., Bianchini Ciampoli, L., and F. D’Amico (2016). An overview of ground-penetrating radar signal processing techniques for road inspections. Signal Processing (132): 201-209.</p><p>[3] Benedetto, A., Benedetto, F., and F. Tosti (2012). GPR applications for geotechnical stability of transportation infrastructures. Nondestructive Testing and Evaluation, 27 (3): 253–262.</p>

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

Deteksi Bentuk Objek Bawah Tanah Menggunakan Pengolahan Citra B-Scan pada Ground Penetrating Radar (GPR)

2017 ◽  
Vol 3 (1) ◽  
pp. 73-83
Author(s):  
Rahmayati Alindra ◽  
Heroe Wijanto ◽  
Koredianto Usman
Keyword(s):  
Signal Processing ◽  
Ground Penetrating Radar ◽  
Post Processing ◽  
Data Survey ◽  
Ground Penetrating

Ground Penetrating Radar (GPR) adalah salah satu jenis radar yang digunakan untuk menyelidiki kondisi di bawah permukaan tanah tanpa harus menggali dan merusak tanah. Sistem GPR terdiri atas pengirim (transmitter), yaitu antena yang terhubung ke generator sinyal dan bagian penerima (receiver), yaitu antena yang terhubung ke LNA dan ADC yang kemudian terhubung ke unit pengolahan data hasil survey serta display sebagai tampilan output-nya dan post  processing untuk alat bantu mendapatkan informasi mengenai suatu objek. GPR bekerja dengan cara memancarkan gelombang elektromagnetik ke dalam tanah dan menerima sinyal yang dipantulkan oleh objek-objek di bawah permukaan tanah. Sinyal yang diterima kemudian diolah pada bagian signal processing dengan tujuan untuk menghasilkan gambaran kondisi di bawah permukaan tanah yang dapat dengan mudah dibaca dan diinterpretasikan oleh user. Signal processing sendiri terdiri dari beberapa tahap yaitu A-Scan yang meliputi perbaikan sinyal dan pendektesian objek satu dimensi, B-Scan untuk pemrosesan data dua dimensi  dan C-Scan untuk pemrosesan data tiga dimensi. Metode yang digunakan pada pemrosesan B-Scan salah satunya adalah dengan  teknik pemrosesan citra. Dengan pemrosesan citra, data survey B-scan diolah untuk didapatkan informasi mengenai objek. Pada penelitian ini, diterapkan teori gradien garis pada pemrosesan citra B-scan untuk menentukan bentuk dua dimensi dari objek bawah tanah yaitu persegi, segitiga atau lingkaran. 

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