• 터널과지하공간
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• 제29권6호
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• pp.468-479
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• 2019

최근 대두되고 있는 지하공간 활용의 필요성 증대에 따라 지하공간의 안정적인 활용을 위해서는 수리-역학적 복합거동에 대한 이해가 필수적이다. 본 연구에서는 향후 국내 다양한 현장 및 지중 조건을 고려한 연구를 수행하는데 도구가 될 수 있는 수치해석을 위한 시뮬레이터를 개발하였다. 이를 위해 지중의 유체역학과 열역학, 역학을 해석하는 과학 소프트웨어 중 하나인 OpenGeoSys와 지반의 여러 역학적 문제들을 해석하는데 전문성을 지닌 FLAC3D를 연계하기로 하였다. 연동해석 기법에 대한 조사를 통해 OpenGeoSys를 주(master)로, FLAC3D를 종속(slave)으로 하여 연계 해석하는 파일 기반의 순차적 연계 방식으로 알고리즘을 개발하였다. 또한, 개발된 시뮬레이터의 검증을 위해 포화된 상태에서의 단상 유체 거동과 관련한 Terzaghi의 압밀 문제를 벤치마크 모델로 선정하여 비교 검증을 수행하였으며, 해석적 해와 수치해석의 결과가 잘 일치하는 것을 확인하였다.

• 한국수자원학회논문집
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• 제31권3호
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• pp.303-308
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• 1998

격자기반의 물수지 기법을 이용하여 강우에 의한 지표흐름과 지표하흐름의 시간적 변화와 공간적 분포를 모의할 수 있는 분포형 강우-유출모형을 개발하였다. 본 모형은 제 수문인자들의 격자별 물수지를 계산하여 단방향 흐름경로 알고리듬에 의하여 지표 및 지표하 흐름을 추적한다. 전처리과정으로서 GRASS를 이용하여 모형에 필요한 ASCII 형태의 자료들을 준비하고, 후처리과정으로서 모형의 수행결과인 유역의 유출량, 유출고, 토양수분, 본포 등을 GRASS상에서 도시할 수 있도록 ASCII형태로 출력하도록 구성하였다.

• 산업기술연구
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• 제19권
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• pp.287-291
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• 1999

This study was performed to develop an information processing system for the sound conservation of soil and groundwater resources. The system contains the geographic spatial information system(GSIS), and the numerical model of groundwater flow and contamination. Numerical models (MODFLOW, MOC3D, MT3D, PMPATH, PEST, UCODE) and GSIS(ArcView) were integrated for the construction of an integrated management system of subsurface environment. The developed system was applied to the management of three mineral water companies located in clean mountain area. The impact of pumping over the overall catchment basin was modeled using the developed system for the decision of future management criteria.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.481-484
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• 2004

A form of measured temperature distribution to estimate condition of a electrical apparatus is a absolute reference for condition of the apparatus, time rate of transition, and difference between reference and currently temperature. Because passive thermography which has not injection of external thermal stimulation shows difference of temperature being on surface of a structure and temperature difference between the structure and back ground, the result could apply only to estimation or monitor for condition of terminal relaxation and overload related with temperature rising. However, a thermal flow in active thermography is differently generated by structure and condition of surface and subsurface. This paper presents the nondestructive testing using the properties and includes the results by heat injection and cooling to the apparatus. The buried discontinuity of subsurface could be detected by these techniques.

• 한국환경복원기술학회지
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• 제12권1호
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• pp.111-122
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• 2009

Abatements of TN and ${NO_3}^-$-N in a horizontal subsurface-flow wetland with litter layer on its surface were compared with those without one. The wetland was constructed in 2001 on floodplain of the Gwangju Stream which flows through Gwangju City in Korea. Its dimensions were 29m in length, 9m in width and 0.65m in depth. A bottom layer of 45cm was filled with crushed granites (15~40mm in diameter) and a middle layer of 10cm had pea pebbles. An upper layer of 5cm contained coarse sands. Reeds (Phragmites australis) growing in natural wetlands were transplanted on its surface. Water of the stream was channelled into the wetland by gravity flow and its effluent was discharged back into the stream. Average Litter layer of 12.2cm was formed on its surface in 2007. The layer and above-ground parts of reeds were eliminated in April 2008. Volumes and water quality of influent and effluent of the wetland were analyzed from May to November in 2007 and 2008, respectively. Inflow into the wetland both in 2007 and 2008 averaged approximately 40$m^3$/day and hydraulic residence time both in 2007 and 2008 was about 1.5days. Influent TN concentration in 2007 and 2008 averaged 3.96 and 3.89mg/L, respectively and average influent ${NO_3}^-$-N concentration in 2007 and 2008 was 2.11 and 2.05mg/L, respectively. With a 0.05 significance level, influent concentrations of TN and ${NO_3}^-$-N, temperatures and pH of effluent, and heights and stem numbers of reeds showed no difference between the wetland with litter layer and without one. TN retention in the wetland with litter layer and without one averaged 64,76 and 54.69%, respectively and ${NO_3}^-$-N removal averaged 60.83 and 50.61%, respectively. Both TN and ${NO_3}^-$-N abatement rates in the wetland with litter layer were significantly high (TN abatement: p<0,001, ${NO_3}^-$-N abatement: p=0.001) when compared with those without one. The subsurface-flow wetland having litter layer on its surface was more efficient for TN and ${NO_3}^-$-N removal.

• 한국환경복원기술학회지
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• 제3권1호
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• pp.62-69
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• 2000

Topography influences shallow landslide initiation through both concentration of subsurface flow and the gradient on slope stability. A model for the topographic influence on shallow landslide initiation developed by Mongomerry et al (1994) is applied to 24 places with similar terrain and subsurface flow. The criterion of landslide prone areas developed by Korea Forestry Administration (1998) is likely to misinterpreted under the condition of heavy rainfall. Soil saturation can be predicted by this model. This relative soil saturation can be used to analyze the stability of each topographic point in the case of cohesionless soils with spatially constant thickness and saturated conductivity. The three different stages of steady state rainfall predicting to cause instability in each topographic points provide a good measure of shallow landsliding possibility.

• 한국지반환경공학회 논문집
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• 제16권6호
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• pp.39-43
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• 2015

This study extends the Distributed Temperature Sensing (DTS) application to delineate the saturated zones in shallow sediment and evaluate the groundwater flow in both downward and upward directions. Dry, partially and fully saturated zones and water level in the subsurface can be recognized from this study. High resolution seepage velocity in vertical direction was estimated from the temperature data in the fully saturated zone. By a single profile, water level can be detected and seepage velocity in saturated zone can be estimated. Furthermore, thermal gradient analysis serves as a new technique to verify unsaturated and saturated zones in the subsurface. The vertical seepage velocity distribution in the recognized saturated zone is then analyzed with improvement of Bredehoeft and Papaopulos' model. This new approach provides promising potential in real-time monitoring of groundwater movement.

• 천문학회보
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• 제46권2호
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• pp.47.2-47.2
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• 2021

The present study is focused on origins of the flow and magnetic structure involved in the formation and eruption of a solar prominence. To clarify them, we performed an MHD simulation based on the 3-dimensional emerging flux tube (3DEFT) model, in which self-consistent evolution of a flow and magnetic field passing freely through the solar surface was obtained by seamlessly connecting subsurface dynamics with surface dynamics. By analyzing Lagrangian displacements of magnetized plasma elements, we demonstrate the flow structure which is naturally incorporated to the magnetic structure of the prominence formed via dynamic interaction between the flow and magnetic field.

• 자원환경지질
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• 제32권5호
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• pp.503-517
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• 1999

The purpose of this study is to verfify a more effecive techique for calculating geothermal gradient. this study examines 370 data of temperature-logging having been collected since 1985. The daya are divided into three different grades grades according to the type of temperature-depth plots: 204 data show typical linear gradient (Grade A); 126 data do not explicitily show the gradient becase of various external effects such as water flow (Grade B); and the rest 40 data do not show the gradient at all (Grade D). The new technique for calculating geothermal gradient is to be required to use Greade-B data more effctiviely. This new technique includes (1) calculating the independer depth of atmospheric temperature in the earth; (2) drawing a distribution map of subsurface tempurature by using the distribution map of subsurface temperature by using Grade-A data at the independent depth; and (3) recalculating geothermal gradient of Grade-B data by using the distrbution map of subsurface temperature, borehole depth, and bottom temperature of Grade-B data by using the distribution map of subsurface temperature, borehole depth, and bottom temperature of Grade-B data. As a result, 330 data-both Grade-A and Grade-B data--can be used to draw a distribution map of hot spradient. The map clearly distinguishes anomaly areas, and helps interpret their relations to the distribution of hot springs, geology, geological structures, and geophysical anomaly areas. These new results reveal that the average of geothermal in south Korea is 25.6$^{\circ}C$/km, when calculated to the Kriging method.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회(1)
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• pp.544-545
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• 2005