• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.81-84
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• 2000

Two-layer aquifer system with fractional flow dimension is composed of contiguous two layers: Layer 1 (lower layer) and Layer 2 (upper layer) with different permeability and specific storage each other. For this aquifer system, we assume that groundwater flow originates only from Layer 1 on the pumping well. The aquifer system considers wellbore storage and skin effects on the pumping well. Dimensionless drawdown curves for different flow dimensions are analyzed for different lambda (λ, crossflow coefficient) values, kappa ($textsc{k}$, permeability ratio between Layer 1 and Layer 2) values and omega ($\omega$, storativity ratio between Layer 1 and Layer 2) values. The curves for Layer 1 and Layer 2 show characteristic trend each other.

• 자원환경지질
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• 제30권5호
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• pp.433-442
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• 1997

균열암반 이중대수층 (1대수층과 2대수층)내 지하수흐름을 모식화한 프락탈모델이 개발되었다 이때 양수정내 지하수유입은 1대수층에서만 유래한다. 본 모델은 우물저장과 우물손실을 고려할 수 있어서 양수초기의 지하수위 변화를 정확하게 파악할 수 있는 잇점이 있다. 여러 가지 유동차원에 대해서, 1대수층의 수리전도도가 2대수층보다 더 크고, 비저유율이 2대수층보다 더 낮은 경우 (case 1)와 1대수층의 수리전도도가 2대수층보다 더 작고, 비저유율이 2대수층보다 더 큰 경우 (case 1)에 대해서 표준곡선을 작성하였으며, 이들 곡선의 특성을 분석하였다. 본 모델은 양수정과 관측정의 수위하강이 서로 다른 거동을 보여주는 양수시험자료를 해석하는데 유용하게 쓰일 수 있을 것이다.

• 자원환경지질
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• 제9권4호
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• pp.225-240
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• 1976

This study deals with the flow of bed rock ground water of Banyaweol Formation, which is presently cleared up as a laminar flow. The result obtained may be summarized as the following. 1) The Banyaweol Formation consists mainly of thin-bedded, green to blackish green shale, mudstone, and marl. The marl and mudstone alternatively occur with shale. The marl and mudstone form a aquifer of Banyaweol Formation. In this study, a group of aquifer is in convenience named as a aquifer zone. The aquifer occurs in lenticular form. The aquifer seems to be a type of artesian aquifer because it is covered with aquicludes, but it actually forms a unconfined aquifer because its piezometric surface stays under the lower aquiclude. The lowering of piezometric level is formed because of leakage of the ground water to the lower aquifer undersaturated. 2) The coefficient of permeability of Banyaweol Formation's ground water body (K) is derived by using Dupuit's equation as the following ${\log}K=\frac{CK^2-dK+f}{aK-b}\;\(M=1.365(2H-s)s\\M={\log}1.956s{\sqrt{H}}r\)$ here, $$a=\sum_{1}M_iG_i$$ $$b={\frac{1}{2}log{\sum_{i}}Q_i{^2}$$ $$c=2{\sum_{i}}M_i{^2}$$ $$d=loge{\sum_{i}}M_{i}Q_{i}+2{{\sum_{i}}N_{i}Q_{i}$$ $$f=loge{\sum_{i}}Q_i{^2}N_i$$ If the measured values substituted for the above equation, the coefficient of permeability of the aquifer is 4.1m/day. The coefficient of storge of the aquifer is $2.8{\times}10^{-4}$ if the measured values substituted for Theis's equation. Using the above constants, the filtration velocity of the aquifer is $2.1{\times}1O^{-1}m/day$and the daily flow quantity of the ground water is $847.38m^{3}/day$. 3) In order to understand the time necessary for a circulation of ground water body, the contents of tritum contained in the ground water are measured as 2.3 T.U. at the Korea Atomic Energy Research Institute. Before 1952, the average concentration of tritium per year in groundwater was reported as 10T. u., taking it as the standard, the groundwater of the present study 26.25 years old. Therofore, the groundwater of the Banyaweol Formation is judged as an relatively old groundwater. It is characteristic that the ground water of Banyawol Formation is laminar flow as well as unconfined aquifer and ground water flow of relatively long time. 4) The nature, means of flow, and circulation of Banyaweol Formation's ground water body make it possible set up this ground water body as a ground water system.

• 한국환경과학회지
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• 제11권1호
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• pp.57-61
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• 2002

To investigate the flow characteristics by the water stage variation between stream-aquifer, the new solution of nonlinear Boussinesq equation was derived and extended using the Boltzmann transformation. The soundness of the analytic solution obtained from this study was examined by the comparison with the linearized analytic solution and the numerical solution by finite difference method. And the movement, velocity, flowrate and volume of flow caused by the stage variation of stream and the existence of regional gradient were estimated. This new analytic solution can express the groundwater movement between stream-aquifer. So, it might be helpful to manage water environment.

• 대한기계학회논문집
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• 제16권9호
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• pp.1780-1787
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• 1992

본 연구에서는 대수층을 시뮬레이션한 실험장치를 통하여 온도분포를 관찰하 고 자연대류에 관한 단순화된 이론적 모델을 개발하여 실험치와 비교 검토하고자 한 다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 춘계학술대회
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• pp.701-704
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• 2005

Aquifer Thermal Energy Storage (ATES) can be a cost-effective and renewable geothermal energy source, depending on site-specific and thermohydraulic conditions. To design an effective ATES system having influenced by groundwater movement, understanding of thermo hydraulic processes is necessary. The heat transfer phenomena for an aquifer heat storage are simulated using FEFLOW with the scenario of heat pump operation with pumping and waste water reinjection in a two layered confined aquifer model. Temperature distribution of the aquifer model is generated, and hydraulic heads and temperature variations are monitored at the both wells during 365 days. The average groundwater velocities are determined with two hydraulic gradient sets according to boundary conditions, and the effect of groundwater flow are shown at the generated thermal distributions of three different depth slices. The generated temperature contour lines at the hydraulic gradient of 0.00 1 are shaped circular, and the center is moved less than 5m to the groundwater flow direction in 365 days simulation period. However at the hydraulic gradient of 0.01, the contour center of the temperature are moved to the end of boundary at each slice and the largest movement is at bottom slice. By the analysis of thermal interference data between two wells the efficiency of the heat pump system model is validated, and the variation of heads is monitored at injection, pumping and no operation mode.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.293-297
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• 2006

Submarine groundwater discharge (SGD) and the interface between seawater and freshwater in an unconfined coastal aquifer was evaluated by numerical modeling. A two-dimensional vertical cross section of the aquifer was constructed. Coupled flow and salinity transport modeling were peformed by using a numerical code FEFLOW In this study, we investigated the changes in groundwater flow and salinity transport in coastal aquifer with hydraulic condition such as the magnitude of recharge flux, hydraulic conductivity. Especially, transient simulation considering tidal effect and seasonal change of recharge rate was simulated to compare the difference between quasi-steady state and transient state. Results show that SGD flux is in proportion to the recharge rate and hydraulic conductivity, and the interface between the seawater and the freshwater shows somewhat retreat toward the seaside as recharge flux increases. Considered tidal effect, SGD flux and flow directions are affected by continuous change of the sea level and the interface shows more dispersed pattern affected by velocity variation. The cases which represent variable daily recharge rate instead of annual average value also shows remarkably different result from the quasi-steady case, implying the importance of transient state simulation.

• 자원환경지질
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• 제54권2호
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• pp.247-257
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• 2021

The study area has been contaminated with explosive materials and heavy metals for several decades. For the design of the pump and treat remediation method, groundwater flow before and during groundwater pumping in a contaminated aquifer system was simulated, calibrated, and predicted using a generalized multidimensional hydrological numerical model. A three-dimensional geologic formation model representing the geology, hydrogeology, and topography of the aquifer system was established. A steady-state numerical simulation with model calibration was performed to obtain initial steady-state spatial distributions of groundwater flow and groundwater table in the aquifer system before groundwater pumping, and its results were illustrated and analyzed. A series of transient-state numerical simulations were then performed during groundwater pumping with the four different pumping rates at a potential location of the pumping well. Its results are illustrated and analyzed to provide primary reference data for the pump and treat remediation method. The results of both steady-state and transient-state numerical simulations show that the spatial distribution and properties of the geologic media and the topography have significant effects on the groundwater flow and thus depression zone.

• 대한지하수환경학회지
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• 제6권4호
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• pp.188-193
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• 1999

지하 대수층에서의 오염물질 이동현상은 지하수 유동에 좌우되며 이를 지배하는 수리지질 파라미터의 결정과 그에 따른 지하수 모델링은 지하수 복원사업에 중요한 역할을 한다. 본 연구의 목적은 실험실 규모의 자유면 대수층에서 획득된 투수계수와 비산출량을 이용하여 다양한 경계조건하에서 지하수 흐름에 대한 민감도 분석을 수행하므로써, 최적의 수리상수를 결정하고 지하수 유동 특성을 파악하는데 있다. 연구결과 모사된 수위저하는 경제조건과 무관하게 관측된 수위저하보다 적게 나타났으며. 투수계수가 비산출율보다 지하수 흐름에 큰 영향을 미치는 것으로 나타났다. 또한 물수지 분석결과 양수시험시 관측정에서 측정된 수위저하는 평형수위나 모사 수위저하보다 크게 나타났으며, 이는 대수층과 우물에서의 수위가 상이함을 지시한다. 이러한 수위의 상이성은 시간영역 광전자파 분석기에 의한 지하수면과 모세관대에서의 수분함량을 관측함으로써 규명되었으며 이는 지하수면 하강시 중력배수의 지연성에 기인하는 것으로 나타났다.

• 방사성폐기물학회지
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• 제18권2호
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• pp.119-131
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• 2020

국내 중·저준위 방사성폐기물 처분시설로 고려되고 있는 표층처분시설의 불포화대에서 핵종 이동을 야기하는 지하수 유동을 평가하기 위하여 유한요소법 기반의 COMSOL Multiphysics을 이용한 수치모델을 개발하였다. 그리고, 처분장 가장자리를 대상으로 처분고, 뒤채움재, 처분덮개로 구성되는 표층처분시설과 그 아래에 위치한 불포화대를 포함한 수직 2차원의 모델 영역을 구성하여, 시나리오 별 모델링을 수행하였다. 지속적 강수 유입 조건과 간헐적 강수 유입 조건 비교에서 포화도의 파동 현상을 제외하고는 뚜렷한 차이점을 보이지 않는 것으로 판단되었다. 불포화대의 공극률이나 잔류함수비와 같은 입력 자료는 전반적으로 불포화대 지하수 유동에 큰 영향도가 없는 것으로 판단되었다. 하지만, 불포화대의 수리전도도는 지하수 유동에 큰 영향을 미치는 것으로 판단되었다. 즉, 처분고로의 지하수 유입 속도를 판단하기 위해서는 불포화대의 수리전도도 특성이 신중하게 고려되어야 할 것으로 판단되었다.