A Study of the Application and the Limitations of GPR Investigation on Underground Survey of the Korean Expressways

Abstract

In this study, the applications and the limitations of the Ground-penetrating radar (GPR) investigation have been addressed with the main objective of improving the efficient GPR application of subsurface surveys on Korean expressways. The depth of investigation and detection performance of anomalous objects have been studied using two different types of multichannel GPR on the Korean Expressway Corporation’s nondestructive testing testbed for subsurface detection. Based on the field survey, it was found that utilizing the plane view by depth, cross-sectional and longitudinal profile data of the multichannel GPR simultaneously, analysis and evaluation of the GPR signals are more efficient and practical. Although there was a difference in the frequency of use, the precision difference between two GPR is almost similar in the investigation depth and detection performance of the pavement subsurface anomaly. Under an asphalt concrete standard pavement section, the effective depth of cavity detection is 1–1.5 m, while detection under concrete pavement is less than 1.0 m. In addition, there is still a need to calibrate depths using field cores when constructing a 3D underground facility map.

Ground-penetration radar detection of Root-mass in a Tree Groove in Southwestern Nigeria

“…GPR Principle:The propagation of radar signals through a medium is governed by the physical principles related to EM waves (Evans et al, 2006). In the GPR Technique, highfrequency electromagnetic pulses (radar) from a transmitting antenna (or an array of antennas) are sent into the subsurface and record is made of the time taken for reflected energy to return to a receiver antenna (Rhee et al, 2021). The passage of radar waves through the medium is dependent on a number of factors including the type of the material of the medium and its condition, and the nature and amount of water it contains.…”

“…The passage of radar waves through the medium is dependent on a number of factors including the type of the material of the medium and its condition, and the nature and amount of water it contains. These properties determine the dielectric constant of the medium The dielectric constant controls the speed of the radar pulse through the medium and the partitioning of its energy between reflection back to the surface and transmission to deeper layers (Rhee et al, 2021). If two materials have sufficiently contrasting dielectric properties, some radar energy is reflected to the surface from the material boundary (Figure . 2).…”

“…GPR systems operate over a wide range of frequencies, usually, 100 MHz to 2000 MHz (Evans et al, 2006), with higher frequencies (≥400 MHz) providing higher resolution in the shallow sections of the material but due to the preferential attenuation of high frequencies, they offer a much-limited depth of investigation (Rhee et al, 2021). This encourages their use for detailed near-surface surveys such as pavement monitoring and mapping reinforced concrete rebar conditions, and root-mass developments.…”

Special Issue “Ground Penetrating Radar (GPR) Applications in Civil Infrastructure Systems”

“…The merits and drawbacks of GPR subsurface surveys on Korean expressways were investigated in the seventh paper [7]. Two different types of multichannel GPR were employed to study the depth and detection performance of abnormal objects.…”

Method of using georadiolocation to control the serviceability of structures during their life cycle

“…Поэтому здесь подчеркивается, что структурный ремонт требуется только тогда, когда структурная система подвергается значительному повреждению; но такая практика неприемлема в случае сооружений стратегического значения, таких как атомные электростанции, плотины крупных водохранилищ, морские и прибрежные сооружения [9]. Сканирование представляет собой трассировку, в которой к значениям амплитуды применена цветовая шкала или шкала серого [21,22,23].…”