• Economic and Environmental Geology
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• v.53 no.5
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• pp.543-552
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• 2020

In this study, we measured groundwater fluxes with a passive flux meter and a borehole dilution test in the Upper Floridan Aquifer. In addition, the feasibility of the passive flux meter is also evaluated within matrix and non-matrix zones. The results of the PFM (5.96 ± 1.75 cm/day) showed good agreement with those of the BHD (4.68 ± 2.99 cm/day) in matrix zones, whereas the results of the PFM (9.94 ± 0.90 cm/day) showed poor agreement with those of the BHD (1817.37 ± 1795.50 cm/day) in non-matrix zones. We assumed that the groundwater passes through the sorbent material inside the PFM. However, it could not pass through the sorbent when the groundwater flux is faster than 11 cm/day. The flow might bypass between monitoring well and the PFM. The PFM used in this study might be suitable for measuring the groundwater fluxes under 11 cm/day. Therefore, more extensive research is needed in the future to measure fast groundwater fluxes (> 11 cm/day).

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.108-112
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• 2004

균열 암반 대수층에 대한 지하수 인공 함양 주입 가능성을 예비적으로 평가하기 위한 시험을 수행하였다. 지하수 인공 함양 주입 시험이 수행된 지역은 경기도 포천군 이동면이며, 이 지역의 지질은 중립내지 조립질 화강암에 해당된다. 시험 정호에 대한 시추공 내부 촬영 결과, 화강암 내에 부분적으로 절리들이 발달되어 있었으며, 대체로 수직적인 절리 발달이 우세하였다. 2개소에서 인공 함양 주입 시험이 100kgf/$\textrm{cm}^2$ 이상의 확장 팩커로 대상공의 상부를 밀폐한 후 시행되었다. 이중 MW-7호 공에서는, 주입 압력을 5 내지 7kg/$\textrm{cm}^2$으로 조절하여 시간당 약 450$\ell$의 평균 주입률로 시험을 수행하였으며, O-7a 호 공에서는 주입 압력을 4kgf/$\textrm{cm}^2$ 내외, 시간당 약 1,740$\ell$의 평균 주입률로 시험을 수행하였다. MW-7호 공의 시험은 3일간 3회에 걸쳐 각 450분, 200분, 414분 동안 시험이 수행되었으며, O-7a호 공에서는 연속적으로 24시간 동안 인공 함양 주입 시험이 수행되었다. 수행된 지하수 인공 함양 주입시험은 적어도 지하수 상류 구배 구간의 지하 수두를 시험이 수행된 이후에도 24시간 이상 유지하는 것으로 평가되었다. 실험을 통해 주입한 양과 주변 관측공의 수위 상승을 단순 검토한 결과 시험이 수행된 지역의 개략적 유효 공극률을 산정 할 수 있었으며, 그 결과, 이 지역 균열 암반의 유효 공극률은 약 3 내지 6% 인 것으로 평가되었다 국내에서 지하수 인공 함양 방식을 균열 암반 대수층에 활용하여, 지속적인 수자원 관리와 수도 공급을 할 수 있는지를 평가하기 위해서는 앞으로 보다 많은 시험수행과 연구를 통한 검증이 요구된다. 까마중, 냉이, 명아주, 둑새풀 등의 생장에 현저한 조해현상을 나타냈다. 이것으로 보아 억새가 타식물의 생장에 영향을 주는 요인물질은 억새의 뿌리에서 분필되는 것으로 생각된다. 옥수수의 뿌리에서 직접 분필하는 물질이나 옥수수뿌리의 분해물질들은 모두 당귀의 생장을 조해하는 경향이 있었다.기존에 제안된 경험식들에 의한 계산결과 보다 균질화 해석법의 결과가 훨씬 정확함을 주목하여야 한다.c의 범위로서 최대값과 최소값은 4차수(four order)의 차이를 보였다. 단열대의 분포 특성을 파악하기 위하여 지구물리검층을 실시하였고, 각 시험에 의해 획득된 결과들과의 비교를 통하여 유동성이 높은 단열들이 규명되었다. 온도검층은 유동성 단열과 일반적인 단열들을 구별하는 좋은 지시자로 나타났다. 그 결과, N70-80$^{\circ}$W.60-85$^{\circ}$NE/SW, N75-80$^{\circ}$W.25-30$^{\circ}$SW, N50-64$^{\circ}$W.60-85$^{\circ}$NE, N35-45$^{\circ}$E.65-75$^{\circ}$SE, 그리고 N65-72$^{\circ}$E.80$^{\circ}$SE/60$^{\circ}$NW의 단열들이 연구지역의 지하수 흐름을 지배하는 뚜렷한 유동성 단열로 규명되었다.eatments. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of c

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.769-777
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• 2016

The objective of this study was to evaluate the stream depletion from groundwater pumping in deep aquifer using the Ward and Lough's analytical solution (2011) which considers a two-layer leaky aquifer system. The calculated results for each pumping from the 110 wells beside streams showed a wide range of non-dimensional stream depletion, that is the streamflow depletion rate divided by the groundwater pumping rate, from lower than 0.1 to more than 0.9 on average for 5 years depending on the specific properties of well location. From the comparison with Hunt's solution (1999) of a single layer aquifer, the Ward and Lough's solution showed about 50% lower than the Hunt's solution due to the difference of hydraulic properties between the first and second layers as well as the lagged effect of vertical leakance. It was also found that the groundwater pumping has a minor effect on the stream depletion if the stream depletion factor (SDF) of the 1st layer is higher than about 1,000 or the SDF of the 2nd layer is higher than about 100, or the vertical leakance is smaller than $10^{-5}s^{-1}$. Furthermore, in the present study, the variations of the stream depletion were assessed according to the magnitude of unmeasured hydraulic properties such as transmissivity and storage coefficient of the 1st layer, vertical hydraulic conductivity of the 2nd layer, the streambed hydraulic conductance.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.192-192
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• 2016

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.4
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• pp.213-223
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• 2004

The discharges of groundwater flow were estimated using Darcy's method along the coastal zone in the Masan Bay. The estimates using the information, i.e., groundwater level, location of the observation well, hydraulic conductivity, the thickness of the aquifer, and coastline length, were 1.65% of the precipitation of the watershed. The estimated groundwater discharges through fractured rock aquifer and the aquifer with sedimentary material were $0.7\times10^4$$m^2/year$and $1.0\times10^7$$m^3/year$ respectively. Whereas, the discharge estimated by KORDI (2003) using isotopes method is about 20 times larger than the estimates from this study because of the influence of the re-circulated seawater through the coastal zone aquifer. In order to quantify this effect in detail, the groundwater levels and salinity changes in the observation wells located in the coastal zone should be continuously monitored and analyzed.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.105-109
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• 2005

폐기물매립장에서 발생하는 침출수의 확산정도를 정량적으로 추정하기 위해 매립장 주변에 설치되어 있는 2개 지하수공(BWM-1, BWM-2)에서 단공주입양수 추적자시험이 실시되었다. 브롬(Br-) 이온이 추적자로 이용되었으며, 추적자시험은 주입단계, 체이서단계 및 양수단계의 과정으로 실시되었다. 시험대상 구간은 지표면하 $20{\sim}24m$에 해당하는 파쇄암반층이며, 주입율과 양수율은 추적자시험 이전에 실시되어진 양수시험 자료에 의해 산정되었다. BWM-1 지하수공의 단공주입양수 추적자시험에 의해 추정된 종분산지수는 공극율이 0.01, 0.05, 0.1 및 0.5인 경우에 각각 9.50, 4.25, 3.00, 1.34cm 이다. 시험대수층의 공극율은 대략 $0.05{\sim}0.20$의 범위이며, 따라서 종분산지수는 $2{\sim}4cm$인 것으로 추정된다. BWM-2 지하수공의 단공주입양수 추적자시험에 의해 추정된 종분산지수는 공극율 0.01, 0.05, 0.1 및 0.5인 경우에 각각 3.32, 1.49, 1.05, 0.47cm 이다. 시험대수층의 공극율은 대략 $0.05{\sim}0.20$의 범위이며, 따라서 종분산지수는 $1{\sim}2cm$인 것으로 추정된다. 폐기물매립장에서 침출수가 유출할 경우, BWM-2 지하수공 주변의 파쇄암반층이 BWM-1 지하수공 주변의 파쇄암반층보다 침출수 확산이 2배 정도 빠르게 발생할 것으로 추정되었다.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.505-513
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• 2016

The qualitative distribution of a fractured aquifer was characterized by electrical resistivity surveying as a part of basic groundwater investigation in Jangseong. The results were then used to choose sites for observation wells. The locations and distributions of permeable discontinuities were studied by analyses of temperature logs, a borehole image-processing system (BIPS), and hydraulic pressure testing using a double packer. The pressure test showed that the size of the discontinuities correlated with the Lugeon value and the results of the temperature log. The results show that temperature measurement is an effective method to identify permeable discontinuities, with the temperature difference correlating with the size of the aperture of the discontinuity.

• Tunnel and Underground Space
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• v.34 no.4
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• pp.374-392
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• 2024

In order to successfully select a site for deep geological disposal of high-level radioactive waste, it is important to perform the stepwise approach along with the systematic selection and survey of evaluation parameters of geological environmental characteristics suitable for the domestic geological environment. In this study, we evaluated the characteristics of hydraulic conductivity, which is considered the most important evaluation parameter in the field of hydrogeology, targeting a deep-depth rock aquifer where actual disposal facilities are expected to be located. In particular, for the first time in Korea, we obtained in-situ pressure-flow data by directly conducting hydraulic tests in boreholes at depths ranging from 500 m to 750 m in various rock types distributed in Korea (granite/volcanic rock/gneiss/mudstone). And we derived hydraulic conductivity values by rock types and depth using verified analytical methods. For this purpose, precision hydraulic testing equipment developed in-house through this study was used, and detailed investigation procedures based on standard test methods were applied to field tests. As a result of the analysis, the average hydraulic conductivity value was found to be in the range of 10^-9 m/s in all granite/volcanic rock/gneiss areas. In the mudstone area, an average hydraulic conductivity value of 10^-11 m/s was derived, which was about 100 times (2 orders of magnitude) lower than that of the fractured rock aquifers. Moreover, permeability tended to slightly decrease with depth in fractured rock aquifers (granite and volcanic rock areas) containing many rock fractures. The gneiss area tended to have large local differences in permeability according to the composition of the stratum and the development of fracture zones rather than depth. In mudstone areas with weak fracture development, there was no significant variation in rock permeability according to depth. The hydraulic conductivity results by various rock types and depth presented in this study are expected to be utilized in building a foundational database for the site selection, design, and construction of disposal facilities in Korea.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.312-315
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• 2006

배수공법으로 터널을 설계할 때 다양한 지질조건에 따라 터널내로 유입되는 지하수 용수량과 배수관의 배수능력을 비교 검토하였다. 기존 설계 기준에 의한 터널 배수관은 다양한 지질조건을 가지는 대수층의 수리전도도에 따라 안정성 여부가 달라지는 것을 알 수 있었다. 기존 배수관 (${\Phi}300m/m$)으로 터널을 설계할 경우 투수성이 좋은 석회암 구간 및 파쇄대 구간에서는 문제가 생길 가능성이 높고, 풍화 받지 않은 암반층의 경우에는 터널길이 20km까지 지하수 용수량을 수용 가능한 것으로 판단된다.

• Geophysics and Geophysical Exploration
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• v.3 no.3
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• pp.88-93
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• 2000

The present study may be summarized as follows. By means of a pole-pole electrical survey, major geological features, i.e, fresh rocks, fractured & weak & saturated rocks, fresh water bearing aquifer, were successfully delineated in the surveyed area of a granite region in Korea. The subsequent Schlumberger sounding and drilling confirmed the existence of the acquifer at 60 m depth as expected. But one more minor acquifer which does not show up in the resistivity depth section was met at 100 m depth. A simple forward modelling leads the authors to believe that any other electrode configuration, e.g., Wenner, Schlumberger, dipole-dipole, pole-dipole, would not detect the deeper aquifer. Under these circumstances, further studies remain to be done in connection with the spatial resolution in the vertical direction.