• The Journal of Engineering Geology
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• v.34 no.2
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• pp.295-315
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• 2024

Urban development and the expansion of electrical resistivity surveying applications have increased the need for soil and underground structure investigations on paved surfaces. Traditional methods involved drilling through the pavement or surveying surrounding soil. Recently, non-invasive surveying techniques have been developed. This paper analyzes these methods, categorizing them into galvanic methods (including drilling and flat ground electrodes) and capacitive coupling methods. By examining case studies, it suggests selecting the appropriate method based on the pros and cons of each and the specific site characteristics. The paper also discusses the applicability and limitations of electrical resistivity surveying through various examples.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.101-106
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• 2008

It is very important to measure reliable properties of each zones in dam for seismic design. But, rock-fill zone which have 80% of total volume and support maintenance mainly during earthquake has little property by field test and seismic design was performed using assumed value. So, it is required that reliable properties have to be evaluated by in-situ test. In this study, surface wave method, which is nondestructive such as SASW and HWAW, was applied to dam to evaluate rock-fill zone of dam. In 2 dams, Vs profiles were evaluated reliably and possibility of suggestion of D/B was verified.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.370-377
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• 2010

In this study, we investigated the current saturation which forces the apparent resistivity to converge when the conductivity contrast between the anomalous body and background medium is greater than a specific value. Analizing theoretical and numerical solutions for some simple models, we studied the behavior of the surface charge, and how the surface charge cause the current saturation and finally lead to the convergence of the apparent resistivity in the resistivity method. As a consequence of above analysis, we verified that the current saturation makes the apparent resistivity converge to a specific value and the magnitude of the apparent resistivity anomaly be less than that of the ideal conductor or insulator in the resistivity method. In general, current saturation is considered to occur when the conductivity contrast becomes larger than 100.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.83-83
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• 2023

댐의 침투수량은 준공이후 댐 안전성 확보를 나타내는 지표 중의 하나이며, 유지관리를 위해 침투수량 측정을 실시하여 관리를 하고 있다. 댐 타입별로 침투수량에 대한 허용치와 관리기준치는 다르지만, 기본적으로 댐에서 발생되는 침투수량은 측정범위를 넘지 않도록 관리를 하고 있다. 댐의 침투수량 측정은 댐 하류에 누수집수벽을 설치하고 댐에서 발생되는 침투수량을 집수한 후 삼각위어를 통하여 침투수량을 측정하고 있다. 이러한 침투수량 측정은 대부분의 댐에서 실시간으로 자동측정하고 있지만, 경우에 따라 미계측 구간이 발생되어 댐 유지관리 측면에서 미계측에 대한 원인분석이 필요한 실정이다. 일반적으로 침투수량의 미계측 원인은 계측기기, 삼각위어, 누수집수벽, 기초지반 등 다양한 원인이 있지만 명확한 원인을 찾기는 어려움이 많다. 특히, 댐 침투수량의 경우 지하수위, 댐 표면 우수, 침투수가 같이 측정되기 때문에 원인분석을 위해서는 다양한 검토가 필요하다. 본 연구의 표면차수벽형석괴댐은 누수집수벽을 통하여 침투수량을 측정하고 있으나, 일부 구간 미계측 부분이 발생하여 기초지반, 댐체 하류사면, 여수로와 댐체 접합부를 통한 누수를 원인으로 추정하였다. 이를 조사하기 위하여 전기비저항 탐사, 시추조사, 수압시험, 지하수위 측정 결과를 이용하여 누수발생 추정위치를 찾고, 침투수량이 미계측되는 원인을 분석하고자 하였다. 전기비저항 탐사는 여수로 접합부, 누수집수벽 상·하류 구간을 선정하여 측정한 결과 상·하류 저비저항대가 존재하는 구간을 추정할 수 있었다. 수압시험 결과 기초암반은 2.3 ~ 21.3 Lu(3.65×10^-5 ~ 3.65×10^-4 cm/sec)의 범위로 누수 가능성이 있는 높은 투수성을 갖는 부분을 확인할 수 있었다. 전기비저항 탐사, 수압시험, 지하수위 측정을 통해 누수집수벽 기초지반 누수발생 원인분석 결과 누수집수벽 기초암반을 통한 누수로 누수집수벽에 댐체를 통한 침투수량이 저류되지 못하는 현상이 발생하기 때문인 것으로 판단되었다. 침투수량계의 정상화를 위해서는 조사를 통해 확인된 누수집수벽 기초암반 누수구간의 그라우팅 보수보강이 필요함을 확인하였다.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.66.1-66.1
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• 2020

우리나라는 최초의 우주탐사선이자 달탐사선인 KPLO를 2022년 8월에 발사할 예정이다. KPLO에는 6기의 임무탑재체가 실리게 되며, 이중 4개의 탑재체는 국내의 대학과 정부출연연구소에서 개발하여 달 표면과 주변 우주환경에 대한 과학임무를 수행하게 된다. 이들 국내에서 개발된 과학탑재체가 달 궤도에서 획득한 Data, 즉 과학자료는 지상국에서 수신하여 이를 처리하여 과학연구 혹은 교육 목적으로 활용될 것으로 예상된다. 이러한 태양계 탐사 과학임무로 부터 획득된 과학자료는 과학의 공익성과 연구교류 활성화를 위해서 국제적으로 대중에게 공개하고 있다. 이에 KPDS도 일반 사용자들이 인터넷으로 이들 과학자료를 쉽게 검색하고 다운로드 받을 수 있도록 한국항공우주연구원에서는 KARI Planetary Data System(KPDS)를 구축하고 있으며, 일반에게 공개할 예정이다. KPDS는 단순히 과학자료를 제공하는 것에서 그치지 않고, 이들 과학자료가 NASA에서 개발한 PDS4 표준을 준수하고 있는지 검증함으로써 세계 각국의 타 우주관련 기관과 상호활용이 용이하도록 하여 활용성을 높은 과학자료로 관리하게 된다. 또한 이러한 PDS4 표준 준수여부를 검증함으로써 KPLO 이후 우리나라에서 수행하게 될 미래의 우주탐사 과학임무로부터 획득될 과학자료도 저장, 공개를 할 수 있도록 KPDS는 범용성을 고려하여 개발하고 있다.

• Journal of the Korean earth science society
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• v.36 no.1
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• pp.16-26
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• 2015

To investigate the applicability of physical prospecting technique in soft ground assessment, the resistivity monitoring data of 6 months are acquired. The Multichannel Analysis Surface Wave (MASW) has been additionally performed to identify the shear wave velocity and strength distribution of soft ground. Moreover, by using the Cone Penetration Test (CPT) and laboratory tests of drilling samples, a relationship with the physical prospect data is checked and the reliability of the physical prospect data is increased. Through these activities, the behavior patterns of soft soil are identified by long term monitoring, and the significant relationship between the shear wave velocity and laboratory tests has been confirmed, both of which can be useful in the surface wave exploration to evaluate the strength of soft ground. Finally, using the geostatistical method, 3-dimensional soil base distribution images are obtained about the combined physical prospecting data with heterogeneous data. Through the studies, the nature of entire area can be determined by long term resistivity monitoring for the soft ground assessment in wider area. It would be more economic and reliable if additional exploring and drilling samples can be analyzed, which can reinforce the assessment.

• Aerospace Industry
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• v.39
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• pp.42-45
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• 1996

태양을 중심으로 그 주위를 돌고 있는 혹성은 모두 9개, 지구까지 합하면 10개라고도 하고 달을 빼고 9개라고도 한다. 사람이 달 표면에 처음으로 착륙한 것이 1969년, 그로부터 30년이 가까워오는 지금 사람은 달 이외에 금성, 화성, 목성, 토성 등 여러 혹성을 탐사하는데 성공했지만 구체적으로 사람이 착륙한 곳은 달 밖에 없다.

• Aerospace Industry
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• v.46
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• pp.54-57
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• 1996

날이 샐 무렵 멀리있는 작은 별들이 자취를 감출 때 서쪽 하늘에 밝게 빛나는 큰 별 속칭 샛별이라는 그 별이 바로 화성이다. 사람들의 눈에 띄기 어려운 시간에 크게 나타나는 별이기 때문에 달처럼 친숙한 많은 이야기는 없지만 인공위성을 띄우고 달나라에 사람을 보내고 달 표면에 흙을 가져온 지구인의 과학은 드디어 화성 탐사에 도전하게 되었다.

• Journal of the Korean earth science society
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• v.35 no.1
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• pp.29-40
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• 2014

A DC resistivity survey was performed to detect anomalies beneath concrete pavement. A set of high conductive media and planar electrodes were used to lessen the effect's a high contact resistance of concrete. Results of the resistivity survey were analyzed and compared with those of other geophysical surveys such as Ground Penetration Radar (GPR), Impulse Response (IR), and Multi-channel Analysis of Surface Waves (MASW), which were carried out in the same location. The results of resistivity survey showed a high resistive distribution in the section of sink and pavement where a pattern of reinforcement was observed through the GPR survey. Also, a comparison of results between the IR and resistivity surveys indicated that the high resistivity was produced by the high dynamic stiffness in the reinforced section. The co-Kriging of both the results of DC resistivity and MASW surveys at the same location showed that an integrated geostatistical analysis is able to give more accurate description on the anomalous subsurface region than can a separate analysis of each geophysical approach. This study suggests that the integrated geostatistical approaches were used for a decision-making process based on the geophysical surveys.

• 한국지구물리탐사학회:학술대회논문집
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• 2002.09a
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• pp.139-162
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• 2002

Since weak zones or geological lineaments are likely to be eroded, weak zones may develop beneath rivers, and a careful evaluation of ground condition is important to construct structures passing through a river. Dc resistivity surveys, however, have seldomly applied to the investigation of water-covered area, possibly because of difficulties in data aquisition and interpretation. The data aquisition having high quality may be the most important factor, and is more difficult than that in land survey, due to the water layer overlying the underground structure to be imaged. Through the numerical modeling and the analysis of case histories, we studied the method of resistivity survey at the water-covered area, starting from the characteristics of measured data, via data acquisition method, to the interpretation method. We unfolded our discussion according to the installed locations of electrodes, ie., floating them on the water surface, and installing at the water bottom, since the methods of data acquisition and interpretation vary depending on the electrode location. Through this study, we could confirm that the dc resistivity method can provide the fairly reasonable subsurface images. It was also shown that installing electrodes at the water bottom can give the subsurface image with much higher resolution than floating them on the water surface. Since the data acquired at the water-covered area have much lower sensitivity to the underground structure than those at the land, and can be contaminated by the higher noise, such as streaming potential, it would be very important to select the acquisition method and electrode array being able to provide the higher signal-to-noise ratio data as well as the high resolving power. The method installing electrodes at the water bottom is suitable to the detailed survey because of much higher resolving power, whereas the method floating them, especially streamer dc resistivity survey, is to the reconnaissance survey owing of very high speed of field work.