• 한국지구과학회:학술대회논문집
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• 2001.09a
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• pp.71-71
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• 2001

• The Journal of Engineering Geology
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• v.4 no.2
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• pp.219-229
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• 1994

Since groundwater flow in fractured rocks is controlled by the distribution of fractures irregu1arly developed in space, it is not possible to understand the hydraulic characteristics of fractured aquifers using Theis equation which is applicable only to homogeneous isotropic confined aquifer. This study deals with the theoretical background of the fractal groundwater flow model with leakage, the methodology of calculation of the hydraulic parameters, and the application of the developed model to field data. From the result of the application of the fractal model to two field data in Hongcheon and Yusung areas, we obtained a good match between theoretical curves and observed curves, with the same hydraulic parameters at the pumping well and the observation well. In the two pumping test analyses, we have determined 1.9 of the fractal dimension. This means that the dimension of groundwater flow at these two sites is slightly smaller than radial flow.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.433-442
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• 1997

A dual-permeability fractal model of fluid flow is proposed. The model simulates groundwater flow in fissured dual aquifer system composed of Aquifer 1 and Aquifer 2. For this model. groundwater flow originates only from Aquifer 1 on the pumping well. The model considers wellbore storage and skin effects at the pumping well and then shows exact drawdown at the early time of pumping. Type curves for different flow dimensions and for two cases are presented and analyzed. The case 1 represents the aquifer system which consists of Aquifer 1 with low permeability and high specific storage and Aquifer 2 with high permeability and low specific storage. The case 2 is inverse to the case 1. Dimensionless drawdown curves in Aquifer 1 and Aquifer 2 shows characteristic trend each other. Consequently, the model will be useful to analyze pumping test data of different draw down patterns on the pumping well and observation wells.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.93-97
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• 2001

시추공의 구간별 수리전도를 추정하는 방법으로는 수압시험(packer test)이 많이 이용되는데 최근에는 유속측정기(flowmeter)를 이용한 시추공 검층법이 개발되어 활발한 연구가 진행 중이다. 본 연구에서는 열원(heat-pulse) 공급 방식의 유속측정기를 이용하여 공주대학 교내에 설치된 시추공에서 자연 유속(ambient flow) 및 양수 유발 유속(pump-induced flow)을 측정하였으며, 자료를 분석하여 수리전도도의 수직적인 분포를 산정하였다. 분석 결과는 수압시험에 의해 산정된 수리전도도의 분포와 잘 일치하였으며, BIPS에 의해 촬영된 시추공 영상 자료와 비교함으로써 지하수 유동과 관련된 투수성 단열(conductive fracture) 들의 수직적인 위치를 정확하게 파악할 수 있었다. 분석 결과는 암반 대수층 내에 발달된 단열망(fracture network)에 대한 3차원적인 정보를 제공할 수 있으며, 이는 효과적인 지하수 모니터링, 모델링, 및 정화 설계(remedial design)에 필요한 기초 자료로 활용될 수 있을 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.31-31
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• 2020

가뭄 발생 시 국내 농어촌 지자체 대부분은 추가 수원공 확보를 위한 긴급 대책으로 신규 관정을 개발하거나, 저수지와 하천을 준설하여 가뭄 수요에 대응하는 편이다. 이러한 방법은 즉시 대응에는 효과가 있지만, 고가의 비용이 소요되고, 무엇보다도 국지적으로 가뭄이 빈번하게 발생하는 지역에는 적용에 한계가 있다. 이러한 한계를 극복하기 위하여, 최근 기설 관정을 연계 이용하여 지하수 공급 극대화를 도모하는 기술이 제안되었다. 그런데 기설 관정 연계 이용 시 가장 중요한 사항은 모든 관정에서 최대 양수량을 유지하며 지하수를 공급할 수 있도록 관리해야 하는 점이며, 특히 암반관정의 과잉양수로 인한 간섭현상으로 충적관정이 고갈되어 공급가능한 지하수 수량이 오히려 감소되는 것을 사전에 방지하여야 한다. 이 연구에서는 가뭄 발생 시 암반관정(양수정)에서 최대로 양수했을 때에도 주변 충적관정의 양수능이 유지되는 최소 지하수위를 「지하수위 저하 한계치」로 지정하여 관정 연계 이용의 최적화를 도모하였다. 지하수위 저하 한계치 산정을 위하여, Theis의 자유면 대수층 정상류 우물수리 방정식과 지하수영향반겅 설정에 관한 경험식(Schultz, Weber, Kozeny 및 Jacob 경험식)을 이용하였다. 그런데 지정된 지하수위 저하 한계치는 충적관정의 지하수위이므로, 암반관측공만 소재하는 지역에 대해서는 충적층 지하수위 변동과 암반층 지하수위 변동 간의 상관분석을 통해 암반 관측공의 지하수위 저하 한계치를 추정하였다. 이후, 양수시험 자료(양수정과 주변 관측공의 수위변동 자료)를 이용하여 지하수 대수층의 이방성을 확인하였고, 이를 통해 암반관정의 양수에 따른 간섭을 크게 받는 충적관정과 그렇치 않은 충적관정을 구분하여 이방성에 따른 지하수위 저하 한계치를 수정하고, 상습가뭄 발생지역의 암반관정과 충적관정의 최적 지하수 양수를 도모하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.1-11
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• 2012

The equation of the step-drawdown test "$s_w=BQ+CQ^p$" written by Rorabaugh (1953) is suitable for drawdown increased non-linearly in the fractured rocks. It was found that value of root mean square error (RMSE) between observed and calculated drawdowns was very low. The calculated $C$ (well head loss coefficient) and $P$ (well head loss exponent) value of well head losses ($CQ^p$) ranged $3.689{\times}10^{-19}{\sim}5.825{\times}10^{-7}$ and 3.459~8.290, respectively. It appeared that the deeper depth in pumping well the larger drawdowns due to pumping rate increase. The well head loss in the fractured rocks, unlike that in porous media, is affected by properties of fractures (fractures of aperture, spacing, and connection) around pumping well. The $C$ and $P$ value in the well head loss is very important to interpret turbulence interval and properties of high or low permeability of fractured rock. As a result, regression analysis of $C$ and $P$ value in the well head losses identified the relationship of turbulence interval and hydraulic properties. The relationship between $C$ and $P$ value turned out very useful to interpret hydraulic properties of the fractured rocks.

• Tunnel and Underground Space
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• v.33 no.5
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• pp.348-372
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• 2023

In relation to the high-level radioactive waste disposal project in deep fractured rock aquifer environments, it is essential to evaluate hydrogeological characteristics for evaluating the suitability of the site and operational stability. Such subsurface hydrogeological data is obtained through in-situ tests using boreholes excavated at the target site. The accuracy and reliability of the investigation results are directly related to the selection of appropriate test methods, the performance of the investigation system, standardization of the investigation procedure. In this report, we introduce the detailed procedures for the representative test method, the constant pressure injection test (CPIT), which is used to determine the key hydrogeological parameters of the subsurface fractured rock aquifer, namely hydraulic conductivity and storativity. This report further refines the standard test method suggested by the KSRM in 2022 and includes practical field application case conducted in volcanic rock aquifers where this investigation procedure has been applied.

• Tunnel and Underground Space
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• v.14 no.3
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• pp.229-240
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• 2004

Coastal aquifers may serve as major sources fur freshwater. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. The management of groundwater in coastal acquifers means making decision as to the pumping rate and the spatial distribution of wells. Several numerical techniques for flow and solute transport simulation can provide the means to achieve this goal. As a basic study to predict the intrusion of seawater in coastal phreatic aquifers, the coupled flow and solute transport analysis was conducted by use of the 3-D finite element code, SWICHA. In order to understand how the location and the shape of freshwater-seawater transition zone were affected by the boundary conditions and hydrogeologic variables, parametric study was carried out.

• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.223-232
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• 1998

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.161-162
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• 2016