• Title/Summary/Keyword: 지표 투과 레이더

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Numerical Analysis of the Ground Penetrating Radar's Return Signal for Mine Detection at Various Frequencies and Soil Conditions (다양한 주파수 및 토양 조건에서 지뢰 탐지용 지표투과레이더 수신신호의 수치해석)

  • Hong, Jin-Young;Ju, Jung-Mung;Han, Seung-Hoon;Oh, Yisok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.23 no.12
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    • pp.1412-1415
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    • 2012
  • Return signals of a ground penetrating radar(GPR) for mine detection at various frequencies and soil moisture contents are analyzed in this paper. We first compute the dielectric constant, conductivity and attenuation loss based on clay loam which is Korea standard soil. The mine-detection images of GPR at various frequencies are also obtained using the finite-difference time-domain(FDTD) technique. Then, the signal-to-clutter ratio(SCR) and received power of the radar are studied. It is shown that the variable frequency channels are suitable for a GPR to detect landmines at various soil conditions.

Safety Evaluation of the Settlement Amount of the Bridge Earthwork Transition Area Using the Ground Penetrating Radar in the Soft Ground Section (연약지반 구간에서 지표투과레이더 활용한 교량 접속부 침하량 안전 평가)

  • Jung, Gukyoung;Jo, Youngkyun;Kim, Sungrae
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.8
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    • pp.17-22
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    • 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.

A Study on the Calculation of Cavity Filling Amount Using Ground Penetrating Radar and Cavity Shaping Equipment (지표투과레이더와 공동형상화 장비를 이용한 공동채움량 산정 연구)

  • Hong, Gigwon;Kim, Sang Mok;Park, Jeong Jun
    • Journal of the Society of Disaster Information
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    • v.18 no.2
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    • pp.261-268
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    • 2022
  • Purpose: In the case of cavity discovered by ground penetrating radar exploration, it is necessary to accurately predict the filling amount in the cavity in advance, fill the cavity sufficiently and exert strength to ensure stability and prevent ground subsidence. Method: The cavity waveform analysis method by GPR exploration and the method using the cavity shape imaging equipment were performed to measure the cavity shape with irregular size and shape of the actual cavity, and the amount of cavity filling of the injection material was calculated during rapid restoration. Results: The expected filling amount was presented by analyzing the correlation between the cavity size and the filling amount of injection material according to the cavity scale and soil depth through the method by GPR exploration and the cavity scale calculation using the cavity shaping equipment. Conclusion: The cavity scale measured by the cavity imaging equipment was found to be in the range of 20% to 40% of the cavity scale by GPR exploration. In addition, the filling amount of injection material compared to the cavity scale predicted by GPR exploration was in the range of about 60% to 140%, and the filling amount of the injection material compared to the cavity size by the cavity shaping equipment was confirmed to be about 260% to 320%.

Proof-of-Concept Research on Pseudo-Random Noise Radar Using Sequential Sampling Method (순차적 샘플링 방식을 이용한 가상 잡음 레이더 개념 증명)

  • Kim, Jihoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.26 no.6
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    • pp.546-554
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    • 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.

Investigation of Underground buried Cables based on Ground Penetrating Radar Data (지표 투과 레이더 데이터 기반 지하 매설 케이블 조사)

  • Choi, SungKi;Yoon, Hyung-Koo;Kim, YoungSeok;Kim, Sewon;Choi, Hyun-Jun;Min, Dae-Hong
    • Journal of the Korean Geotechnical Society
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    • v.40 no.2
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    • pp.105-113
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    • 2024
  • Underground buried cables can cause disconnections during the construction of roads and other subterranean structures due to uncertain designs. This paper describes experiments conducted to detect and verify the locations of these cables utilizing ground penetrating radar (GPR). The experiments were carried out at an active road construction site, where cable burial was anticipated. The GPR used operated within a frequency range of 400 MHz to 900 MHz to probe underground structures. The exploration methodology consisted of an initial GPR test to survey the entire area, followed by a secondary test informed by the results of the initial experiment, incorporating a diverse and increased number of lines. The findings confirmed the hyperbolic reflection patterns of cables at consistent locations along the same lines. These patterns were then compared to existing designs to corroborate the presence of cables at the identified locations. This research establishes an effective GPR methodology based on the electromagnetic wave reflection pattern, specifically the hyperbola, to detect difficult-to-locate underground buried cables.

A Ground Discovery System based on Graph Data (그래프 데이터 기반의 지반 탐사 시스템)

  • Song, Je-O;Kwon, Jin-Gwan;Choi, Do-jin;Yoo, Jae-Soo
    • Proceedings of the Korea Contents Association Conference
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    • 2018.05a
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    • pp.499-500
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    • 2018
  • 최근 지반이 가라앉아 지면에 구멍이 발생하는 싱크홀(Sink Hole)의 발생이 빈번하게 발생하고 있으며, 이에 대한 피해사례도 증가하고 있다. 이를 예방하고 대응하기 위하여 국가적으로 대대적인 지반조사를 하고 있으며 해당 지반을 탐사하기 위하여 지표투과레이더와 내시경 등을 활용한 방법을 사용하고 있다. 본 논문에서는 현재까지 가장 효율적인 방법으로 알려진 지표투과레이더의 데이터를 그래프 형태로 표현하고 분석하여 효과적으로 탐사를 할 수 있는 시스템을 제안한다.

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Evaluation of Concrete Bridge Deck Deterioration Using Ground Penetrating Radar Based on an Extended Common Mid-Point Method (확장형 공통중간점법 기반 지표투과레이더를 이용한 콘크리트 교량 바닥판 열화 상태 평가)

  • Baek, Jong Eun;Lee, Hyun Jong;Oh, Kwang Chin;Eom, Byung Sik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.6
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    • pp.82-92
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    • 2012
  • This study proposed a new non-destructive evaluation method for concrete bridge deck deterioration using ground penetrating radar (GPR). To calculate dielectric constant of the concrete bridge deck, an extended common mid-point (XCMP) method was developed for a two-layered structure using an air-coupled GPR antenna setup. The deterioration conditions of the concrete bridge deck such as deterioration depth was evaluated based on the dielectric constant and surface-to-average dielectric constant ratio of the concrete bridge deck. A GPR field test was conducted on an old concrete bridge with asphalt concrete surfacing to validate the new evaluation method. The test results showed that the newly proposed method estimated pavement thickness and deterioration depth of the concrete deck in a reasonable level.

Study of Application for Using Nondestructive Method in Gravel Area (사석 성토 지역의 비파괴 조사 기법 적용성 연구)

  • Yoon, Hyung-Koo
    • Journal of the Korean Geotechnical Society
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    • v.39 no.7
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    • pp.49-56
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    • 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.

Three-dimensional Finite-difference Time-domain Modeling of Ground-penetrating Radar Survey for Detection of Underground Cavity (지하공동 탐지를 위한 3차원 시간영역 유한차분 GPR 탐사 모델링)

  • Jang, Hannuree;Kim, Hee Joon;Nam, Myung Jin
    • Geophysics and Geophysical Exploration
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    • v.19 no.1
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    • pp.20-28
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    • 2016
  • Recently many sinkholes have appeared in urban areas of Korea, threatening public safety. To predict the occurrence of sinkholes, it is necessary to investigate the existence of cavity under urban roads. Ground-penetrating radar (GPR) has been recognized as an effective means for detecting underground cavity in urban areas. In order to improve the understanding of the governing physical processes associated with GPR wave propagation, and interpret underground cavity effectively, a theoretical approach using numerical modeling is required. We have developed an algorithm employing a three-dimensional (3D) staggered-grid finite-difference time-domain (FDTD) method. This approach allows us to model the full electromagnetic wavefield associated with GPR surveys. We examined the GPR response for a simple cavity model, and the modeling results showed that our 3D FDTD modeling algorithm is useful to assess the underground cavity under urban roads.

Automatic Detection System of Underground Pipe Using 3D GPR Exploration Data and Deep Convolutional Neural Networks

  • Son, Jeong-Woo;Moon, Gwi-Seong;Kim, Yoon
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.2
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    • pp.27-37
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    • 2021
  • In this paper, we propose Automatic detection system of underground pipe which automatically detects underground pipe to help experts. Actual location of underground pipe does not match with blueprint due to various factors such as ground changes over time, construction discrepancies, etc. So, various accidents occur during excavation or just by ageing. Locating underground utilities is done through GPR exploration to prevent these accidents but there are shortage of experts, because GPR data is enormous and takes long time to analyze. In this paper, To analyze 3D GPR data automatically, we use 3D image segmentation, one of deep learning technique, and propose proper data generation algorithm. We also propose data augmentation technique and pre-processing module that are adequate to GPR data. In experiment results, we found the possibility for pipe analysis using image segmentation through our system recorded the performance of F1 score 40.4%.