• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.344-351
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• 2003

Hydrogeological survey and geochemical analysis were carried out in Phra Yun area, Northeast Thailand, which is a typical salt-affected area for an understanding of hydrogeological groundwater behaviours. Geological survey reveals the presence of G1 and F1 faults. Electromagnetic ground conductivity prospecting shows that the high conductivity zones of 15 mS/cm or more are distributed at underground of the G1 and F1 faults where saline groundwater is discharged. The distribution patterns of tritium concentration show that high tritium concentration zones of groundwater were recharged from pond and river. On the assumption that the annual average tritium concentration of precipitation in Northeast Thailand is same as tritium concentration of precipitation in Tokyo and groundwater flows as piston flow, the age of recharging precipitation of groundwater with 15 TU in 1997 could be estimated at 1967-1970 years. The velocity of groundwater flow was calculated to be $5.3{\times}10^{-7}\;m/s\;and\;2.1{\times}x10^{-6}\;m/s$ respectively from a duration time of 30 years and distance of groundwater flow 500m -2000m from the pond and river to the investigation wells. Because the estimated values of velocity of groundwater flow are compatible with the hydraulic conductivities, it is considered that 30 years is a reasonable period for recharging groundwater.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1987년도 제29회 수공학연구발표회논문초록집
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• pp.113-122
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• 1987

A numerical simulation technique of three-dimensional finite difference model is developed to study the groundwater flow system in Dcjima, an upland area which faces Kasumigaura Lake. For general perspectives of the groundwater flow system, a steady state three-dimentional model is simulated. For the sedimentary mud formations which are found in the representative formation, three situations of hydraulic conductivity are considered, representing an isotropic condition and situations where the horizontal permeability is equal to 10 times and 100times of the vertical one. The finite difference grid used in the simulation has 60x50x30=90,000 nodes. A converged solution with a tolerance of 0.001 meter of hydraulic head is set. Having determined the flow net by using a steady state three-dimensional model. the results for the three cases of hydraulic conductivity are compared with the results of tracer methods (Bae and Kayane 1987) With the aid of four representative vertical cross-sections, groundwater flow systems in the study area are assumed. Water balances for the three cases indicate very good agreement between total recharge and discharge in each case Analyses of groundwater flow system based on the tritium concentrations and water quality measurements (Bae and Kayane 1987) are confirmed by the numerical simulation and the results obtained by these two methods appeared to be in close agreement.

• 토지주택연구
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• 제8권1호
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• pp.13-22
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• 2017

In this study, triggering mechanism of ground sinking was analyzed through groundwater flow analysis on the basis of a case of the ground sinking occurred in Yongsan in 2015. The results of geotechnical investigation performed before and after the ground sinking were analyzed for the accurate understanding of geological features in the study area. The numerical groundwater flow analysis was performed to evaluate the influence of the flow behavior from the surrounding area toward the excavated site using software of Visual MODFLOW. As a result, it was found from the geotechnical analysis that the strata of sedimentary layer along the sunken area in the vertical direction was mixed significantly after the ground sinking compared with the status of the soil condition before the ground sinking. Piping was occurred at the toe of cut-off wall in the sandy gravel layer, and this phenomenon was predicted by the numerical flow analysis. Sequential ground displacement scenario of the ground sinking was derived from the geotechnical in situ test and numerical flow analysis performed in this study.

• 한국수자원학회논문집
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• 제33권5호
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• pp.611-622
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• 2000

본 연구에서는 제주도 서귀포유역의 지하수 유동시스템 해석을 위해 MODFLOW 모델을 이용하였으며 양수량 측정자료를 통한 투수량계수 및 저류계수를 초기치로 선정하여 시행착오법을 통한 대상유역의 최종 매개변수를 얻을 수 있었고 모델의 모의 발생을 한 결과 지하수유동시스템에 대한 적용성이 잘 반영됨을 알 수 있었다. 서귀포 유역은 지형지질을 고려한 관측치 해석, 이(1996)의 연구결과 및 모의발생을 통한 결과로 볼 때 지하수두 분포는 표고 400m이내에서 안정된 지하수 함양에 의한 용출이 이루어지고 있는 것으로 판단된다. 또한, 부정류상태하에서 지하수 유동경로 해석을 위하여 수두분포의 결과치를 이용한 유속벡터 분석을 실시한 결과 유속벡터가 상대적으로 크게 나타난 지역은 II, III 및 Ⅵ지점이었으며 지하수 유동경로는 I, II, III, IV, V, Ⅵ 및 Ⅶ지점의 각 방향으로 분산되어 유출되고 있음을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.539-552
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• 2013

To establish an aging management plan considering seawater influx and changes in groundwater within nuclear power plant sites, the characteristics of groundwater flow must be understood. This study investigated the characteristics of groundwater flow within the site and analyzed groundwater level recorded by monitoring wells to evaluate groundwater flow characteristics and elements that affected these characteristics for supplying the information to conduct the appropriate aging management for ensuring the safety of the safety-related structures in Shin Kori Unit 1 and 2. The increase in groundwater level during the wet season results from high sea-level conditions and the large amount of precipitation. As a result of the analysis of groundwater distribution and change characteristics, the site could be divided into a rainfall-affected area and a tide-affected area. First, the rainfall-affected area can further be divided into areas that are affected simultaneously by excavation, backfill, and a permanent dewatering system. Secondly, areas that are not affected by excavation, or the dewatering system, or by structure arrangement and excavation. Analysis of the spectrum for wells affected by tides resulted in confirmation of the M2 component (12.421 hr) and S2 component (12.000 hr) of the semidiurnal tides, and the O1 component (25.819 hr) of the diurnal tides. In the cross-correlation results regarding tides and groundwater levels, the lag time occurred diversely within 1-3 hours by the effect of the well location from sea, the distribution of the backfill material with depth, and the concrete structure.

• 농업과학연구
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• 제45권3호
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• pp.521-532
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• 2018

In recent decades, the dry stream phenomena of small and medium sized rivers have been attracting much attention as an important social problem. To prevent dry stream phenomena, it is necessary to build an infrastructure that manages rivers. To accurately determine the progress of dry stream phenomena, it is necessary to continuously measure the discharge and other hydrological factors for small and medium sized rivers. However, until now, the flow data for small and medium rivers in Korea has been insufficient. To overcome the lack of supporting data for supporting rational decision-making in policy and project implementation, a short- and long-term hydrological model was developed that takes into consideration hydrological changes such as the increase of the impervious area due to urban development and groundwater pumping, the construction of a large-scale sewage treatment plant, the maintenance of stream-oriented rivers, etc. In the developed model, the distributed grid is represented by three layers: Surface flow, interflow, and groundwater flow. The surface flow and intermediate flow flowed along the flow direction, and the groundwater flow was calculated by a two-dimensional groundwater analysis model such that the outflow occurred in all directions without a specific flow direction. The effects of land use and cover on evapotranspiration and infiltration and the effects of multiple landscapes can be simulated in the developed model.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.351-356
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• 2002

Groundwater recharge rate was estimated by applying the groundwater level fluctuation method utilizing Theis (1937) approach with specific yield estimation technique of Shevenell (1996) and the temperature method using observed data from National Groundwater Observation Stations. Results based on analysis of water level observation data of 10 alluvium wells reveal that the recharge rates for 5 wells of Kum river area range 3.7~25.0% and those for 5 wells of Nakdong river area range 3.6~21.7%. Results obtained from the temperature method based on water temperature data indicated that the upward flow resulted from evapotranspiration is dominant for 4 wells of the Kum river area and 5 wells of the Nakdong river area. The other wells showed the downward flow which is related to groundwater recharge in these areas.

• 터널과지하공간
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• 제27권4호
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• pp.205-216
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• 2017

지하수위 변동은 석회석 폐광산에서 발생하는 지반침하의 주된 요인이다. 본 연구에서는 지하수로 포화된 석회석 채굴공동에서 발생하는 지하수 유동을 자연상태와 골재 충전, 임시배수로 구분하여 지반 안정성에 미칠 영향을 3차원 지하수 유동 해석을 통해 평가하였다. 해석 결과 골재 충전시 지반 및 소류지의 지하수위가 상승하였지만 강우나 소류지 농업용수 사용으로 발생하는 수위차 보다 작고 유속 또한 자연상태의 유속과 유사하게 나타났다. 임시배수시에는 지반 및 소류지의 지하수위가 급격하게 하강하고 공동 내 유속이 최대 25배 이상 증가하는 것으로 나타나 지반침하 위험성이 증가하는 것으로 나타났다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.103-110
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• 1996

In this paper, behaviour of underground structural systems due to excavation and change of groundwater level is analyzed using finite elements. Equilibrium equations based on the effective pressure theory and transient flow equations considering the groundwater level are derived. Integration equations are derived using Galerkin's approximation and time dependent analysis is employed to compute groundwater level change and pore pressures. This computed pore pressures are employed in equilibrium equations and then finally displacements and stresses are computed. The developed program is applied to analyze the behaviour of ground excavation below the groundwater level. The program is also applied to multi-step excavation at the same model. The results show that the displacements of the ground surface are much influenced by the change of the groundwater level. Therefore, it is concluded that the change of the groundwater level should be considered in order to analyze the behaviour of the underground structural systems accurately

• 한국지구과학회지
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• 제42권4호
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• pp.383-389
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• 2021

Several studies investigating the behavior and environmental distribution of rare earth elements (REEs) have been reviewed to determine the geochemical processes that may affect their concentrations and fractionation patterns in groundwater and whether these elements can be used as tracers for groundwater-rock interactions and groundwater flow paths in small catchments. Inductively coupled plasma-mass spectrometry (ICP-MS), equipped with an ultrasonic nebulizer and active-film multiplier detector, is routinely used as an analytical technique to measure REEs in groundwater, facilitating the analysis of dissolved REE geochemistry. This review focuses on the distribution of REEs in groundwater and their application as tracers for groundwater geochemistry. Our review of existing literature suggests that REEs in ice cores can be used as effective tracers for atmospheric particles, aiding the identification of source regions.