• Title/Summary/Keyword: 전기탐사

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Dam seepage investigation using two- and three-dimensional resistivity surveys (2차원 및 3차원 전기비저항 탐사를 이용한 제당 누수 조사)

  • Yi Myeong-Jong;Kim Jung-Ho;Song Yoonho;Chung Seung-Hwan
    • 한국지구물리탐사학회:학술대회논문집
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    • 2000.09a
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    • pp.41-53
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    • 2000
  • Electrical resistivity survey is widely applied to the dam seepage problems. Main purpose of the resistivity survey is to delineate the inhomogeneity in the dam. In this study, two- (2-D) and three-dimensional (3-D) resistivity survey methodology and corresponding interpretations of the data have been analyzed using 3-D resistivity modeling results. Since resistivity structures beneath the dam and its shape are 3-D in nature, we could get more accurate image of the dam structures using 3-D survey compared to 2-D survey even though we cannot employ the grid-shape survey layout.

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Distortion of Resistivity Data Due to the 3D Geometry of Embankment Dams (저수지 3차원 구조에 의한 전기비저항 탐사자료의 왜곡)

  • Cho, In-Ky;Kang, Hyung-Jae;Kim, Ki-Ju
    • Geophysics and Geophysical Exploration
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    • v.9 no.4
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    • pp.291-298
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    • 2006
  • Resistivity method is a practical and effective geophysical technique to detect leakage zones in embankment dams. Generally, resistivity survey conducted along the crest assumes that the embankment dam has a 2D structure. However, the 3D topography of embankments distorts significantly resistivity data measured on anywhere of the dam. In this study, we analyse the influence from 3D effects created by specific dam geometry through the 3D finite element modeling technique. We compared 3D effects when resistivity surveys are carried out on the upstream slope, left edge of the crest, center of the crest, right edge of the crest and downstream slope. We ensure that 3D effect is greatly different according to the location of the survey line and data obtained on the downstream slope are most greatly influenced by 3D dam geometry. Also, resistivity data are more influenced by the electrical resistivity of materials constituting reservoir than 3D effects due to specific dam geometry. Furthermore, using resistivity data synthesized with 3D modeling program for an embankment dam model with leakage zone, we analyse the possibility of leakages detection from 2D resistivity surveys performed along the embankment dam.

A Geophysical Survey of an Iron Mine Site (철광산 지역에서의 물리탐사 기술 적용 연구)

  • Kim, Kiyeon;Oh, Seokhoon
    • Journal of the Korean earth science society
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    • v.34 no.6
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    • pp.575-587
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    • 2013
  • DC electrical and electromagnetic survey was applied to evaluate the reserve of an iron mine site. We analyzed the borehole cores and the cores sampled from outcrops in order to decide which geophysical method was efficient for the evaluation of iron mine site and to understand the geological setting around the target area. Based on the core tests for specific weight, density, porosity, resistivity and P-wave velocity, showing that the magnetite could be distinguishable by the electrical property, we decided to conduct the electrical survey to investigate the irone mine site. According to previous studies, the DC electrical survey was known to have various arrays with high resolutions effective to the survey of the iron mine site. However it was also known that the skin depth is too shallow to grasp the deep structure of iron mine. To compensate the weakness of the DC electrical method, we applied the MagnetoTelluric (MT) survey. In addition, a Controlled Source MT (CSMT) method was also applied to make up the shortcoming of MT method which is weak for shallow targets. From the DC electrical and MT survey, we found a new low resistivity zone, which is believed to be a magnetite reserve beneath the old abandoned mine. Therefore, this study was confirmed for additional utility value.

3D Resistivity Survey at a Collapsed Tunnel Site (붕락 터널에서의 3차원 전기비저항 탐사)

  • Cho, In-Ky;Kim, Ki-Seog;Lee, Keun-Soo
    • Geophysics and Geophysical Exploration
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    • v.18 no.1
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    • pp.14-20
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    • 2015
  • Three-dimensional (3D) resistivity method is an effective tool in the engineering site survey because it can provide a 3D resistivity distribution of the site. In this study, we tried to find out faults, fractures and coal seams that can cause the collapse of the tunnel. We carried out 2D resistivity survey along 5 parallel lines and 11 cross lines and merged all the apparent resistivity data for 3D inversion. Finally, from the 3D resistivity image and drilling data we presented the 3D distribution of faults, fractures and coal seams that are considered the main cause of the tunnel collapse.