• Corrosion Science and Technology
• /
• v.3 no.6
• /
• pp.262-264
• /
• 2004

Ground Penetrating Radar (GPR) has been used to image inside concrete specimens embedded with steel bars and delamination. An imaging algorithm has been developed to improve measurement output generated from a commercial radar system. For the experiments, laboratory size concrete specimens are made with the dimensions of $1,000mm(W){\times}1,000mm(L){\times}250mm(D)$. The results have shown improved output of the radar measurements compared to commercially available processing methods.

• Journal of the Korean Geotechnical Society
• /
• v.39 no.7
• /
• pp.49-56
• /
• 2023

Gravel is commonly employed to enhance the bearing capacity of foundations and provide stable support for structures. However, effectively assessing the ground characteristics in the presence of gravel poses significant challenges. This study aims to compare the resolution of ground containing gravel using electrical resistivity, elastic wave surveys, and ground penetration radar (GPR). Nondestructive methods are applied at construction sites where soil improvement is carried out using gravel. The experiments focus on shallow depths, and the obtained results cover depths up to 2 m. Both the electrical resistivity and elastic wave techniques exhibit similar behavior in their findings, indicating comparable outcomes. However, GPR has limitations in observing the characteristics of ground with gravel. Dynamic cone-penetration tests were conducted to validate these findings. The electrical resistivity and elastic wave profiles exhibited similar behaviors in localized areas, further supporting their compatibility and reliability.

• Journal of the Korean Geotechnical Society
• /
• v.31 no.11
• /
• pp.41-48
• /
• 2015

An investigation of a void and a loose layer of the ground is essential in order to prevent the losses of life and properties caused by subsidence and sinkage of the ground. Recently, studies on the ground penetrating radar survey have been actively conducted in order to estimate the void and the loose layer of the ground. However, an error can be committed by contrarily predicting a dense ground and a loose layer because the ground penetrating radar estimates an interface depth between geo-materials that have different electrical impedances. In this study, a loose ground depth is estimated using the characteristics of the reflected electromagnetic wave obtained from the ground penetrating radar survey. To gather the signals according to the loose ground depths, the ground penetrating radar survey is conducted on a field which underwent a huge ground settlement. In addition, the dynamic cone penetration test is performed to verify the result of the loose ground depth estimation from the ground penetrating radar survey. From the analysis of the reflection characteristics of the electromagnetic wave, a phase of an electromagnetic wave reflected from a denser soil layer is found to be identical with that of the first measured signal. On the other hand, a phase of an electromagnetic wave reflected from the loose soil layer is found to be opposed to that of the first detected signal. The comparison between the dynamic cone penetration index and electromagnetic signals by the ground penetrating radar shows that the estimated depth of the loose or dense layer is perfectly matched with a high reliability. The ground penetrating radar survey and the signal analysis performed in this study can be used not only for the survey of interface depth between the discontinuity layers but also for the estimation of the loose layer.

• Journal of the Korean Geotechnical Society
• /
• v.29 no.9
• /
• pp.17-29
• /
• 2013

The geophysical methods have an advantage for investigating the wide area with low cost, and thus the application of these methods has been increased. The objective of this paper estimates the characteristics of alluvium through the geophysical methods including elastic wave, electrical resistivity and ground penetration radar. And the standard penetration test is also carried out for verifying the geophysical data with comparison. The sources of elastic wave method are divided into hammer and sissy and the electrical resistivity method is applied with different sizes, shapes and arrays of electrode for deciding the effective way. The center frequency is determined to be 270 MHz for considering the characteristics of soil. The results of ground penetration radar are also compared with those of standard penetration test. The high resolution shows when the source is a sissy in elastic wave method, however, the water level is not identified. In the electrical resistivity method, the non-polarizable electrode and schlumberger array show highly reliable data and the resolution of ground penetration radar is low. Thus, the results of this study are widely applied for determining the appropriate method when investigating the characteristics of alluvium.

• The Journal of Engineering Geology
• /
• v.29 no.4
• /
• pp.553-563
• /
• 2019

In order to survey archaeological sites, drilling and excavation are carried out at the final stage. However, at the preliminary stage, non-excavation geophysical prospection is used for assessing underground archaeological ruins. Among the geophysical prospecting techniques, Ground Penetration Radar (GPR) prospection has effectively been applied to historical sites due to its high resolution at shallow depths. In this study, the GPR prospection was conducted to find underground ruins near Suseong-Dang, the place of ancient rituals in Buan area, Korea. First, the GPR prospection was conducted at three sites (Site-1, 2, and 3), and subsequently, the GPR prospection was carried out at Site-3 in more detail. As a result of the prospection, the underground layered structure of the survey area consists of three layers, which are soil layer, weathered rock, and sound rock from the surface. And the GPR anomaly to the archaeological structure was clearly identified at around 100-cm depth showing est-west direction that is parallel to the long-axis array. This GPR anomaly of irregular geomorphological features and intermittent distribution may be related to the ritual remains found in Suseong Dang. The GPR prospection could be effectively used to detect archaeological sites or remains buried in the ground.

• Journal of the Korean GEO-environmental Society
• /
• v.23 no.8
• /
• pp.17-22
• /
• 2022

To reduce the bump of bridge/earthwork transition area caused by the settlement of the soft ground during public use, the road agencies have been continuously overlay or repavement at those areas. In this study, the vehicle-mounted ground penetrating radar with 1GHz air-coupled antenna was used to estimate the settlement amount of those areas for nine bridges built in the soft ground. Results shows that it is possible to effectively measure the thickness of pavement up to a depth of 1 m on an asphalt road with ground penetrating radar technology that can inspect under the road surface. Distinctively deformation of the road surface, the variation in the thickness of the pavement measured at bridge/earth transition areas is equivalent to a minimum of 50 mm and a maximum of 600 mm, and there is a risk of cavity in the ground. The difference in the increased pavement thickness is 50~250 mm for each bridge connection, which may cause the differential settlement. In this study, by using the result of the ground penetration radar, a plan for improving drivability and maintenance of the settlement is suggested and applied to the field.

• Spatial Information Research
• /
• v.14 no.1 s.36
• /
• pp.57-65
• /
• 2006

In general, the investigation for reservoir dredging are conducting a observation on the horizontal position and the depth of water by assembling GPS/Echo Sounder and Total Station/Echo Sounder, and it is computed at a section computation of riverbed, reservoir volume and dredging plan etc. at that times, the detail plane is determinated about soil volume, height for dredging. Planning has a fault that the method of sound detection using the Echo Sounder doesn't check up distribution of reservoir deposit. In this study, the author emphasizes that implementation of dredging with combined Global Positioning System(GPS) and Ground Penetration Radar(GPR) is well-done more than existed GPS/Echo Sounder. the combined equipment can be adapted to computation and dredging reffering to distribution of deposition. First of all, it is executed water tank modelling test through sampling for apply to test area and is estimated the possibility after passed far accuracy verification of equipment.

• Electronics and Telecommunications Trends
• /
• v.30 no.5
• /
• pp.22-27
• /
• 2015

도로함몰 사고 증가를 계기로 지하 구조물의 안전 관리 방법, 특히 비파괴 검사 장비에 대한 관심이 고조되고 있다. 지중투과 레이더 기술은 전자파의 투과, 반사 특성을 이용한 비파괴 검사 기술로써 투과 깊이, 투과 해상도 등 비파괴 검사 성능 측면에서 가장 주목받고 있는 기술이다. 본고에서는 지중투과 레이더 기술의 특징, 국외 제품 동향을 살펴본다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.26 no.6
• /
• pp.546-554
• /
• 2015

Ultra-wideband(UWB) radar is widely used in many penetration radar applications, such as ground-penetrating radar and foliage-penetrating radar, because it has many advantages in detecting concealed objects. One type of UWB radar system is random noise radar, which many be robust to jamming environment. However conventional random noise radar requires high-speed analog-to-digital convertor(ADC) for matched filtering. In this thesis, a pseudo-random noise radar system that maintains anti-jamming characteristics but does not require high-speed ADC is researched. and The UWB system is implemented in a low frequency system, and its performance has been demonstrated by experiment, which proves the concept of the proposed pseudo-random noise radar system.

• Journal of Satellite, Information and Communications
• /
• v.7 no.1
• /
• pp.75-81
• /
• 2012

This study is to design the transmitter and receiver of short range UWB(Ultra Wide Band) imaging radar that is able to display high resolution radar image for front area of a UGV(Unmanned Ground Vehicle). This radar can help a UGV to navigate autonomously as it detects and avoids obstacles through foliage. The transmitter needs two transmitters to improve the azimuth resolution. Multi-channel receivers are required to synthesize radar image. Transmitter consists of high power amplifier, channel selection switch, and waveform generator. Receiver is composed of sixteen channel receivers, receiver channel converter, and frequency down converter, Before manufacturing it, the proposed architecture of transceiver is proved by modeling and simulation using several parameters. Then, it was manufactured by using industrial RF(Radio Frequency) components and all other measured parameters in the specification were satisfied as well.