• Journal of Wetlands Research
• /
• v.13 no.2
• /
• pp.265-273
• /
• 2011

Hyporheic zone, where groundwater-stream water mixing occurs, sensitively responds to heat of groundwater and stream water temperature. Variation of stream water temperature has short time period and time dependent, because stream water temperature is influenced by daily fluctuation and seasonal air temperature. On the other hand, groundwater temperature is insignificant. In this study, we conducted 1-dimensional heat transfer analysis. The results show that there are differences of temperature distribution between gaining stream and losing stream with flux in hyporheic zone. Especially, variations of hyporheic water temperature show a significant difference in adjacent streambed, Also, the results shows that distribution of temperature was more affected by groundwater direction than intensity of flux.

• Journal of the Korean Society of Groundwater Environment
• /
• v.3 no.2
• /
• pp.51-59
• /
• 1996

In case waste disposal site is to be constructed close to the underground facilities such as LPG storage cavern which is completely maintained by groundwater pressure, it is generally requested that the possibility on leachate contamination of cavern area be reviewed and the countermeasure, if it is estimated cavern area is severely affected by leachate, be taken into consideration. Prediction was performed and leachate control plan was made using by analytical and the numerical analysis on the leachate migration which is likely to happen at the area between the proposed waste disposal site and the underground LPG storage cavern located at the U petrochemical complex. Analytical solutions were obtained by the conservative mass advection-diffusion equation and the effect of advection and dispersion factor on the leachate migration was reviewed through peclet number calculation and the functional relationship between the factors and leachate transport velocity was established, which leads to enable us to predict the leachate transport velocity without difficulties when different parameters (factors) are used for analytical solution. Numerical solutions were obtained by FEM using AQUA2D which is for the simulation of groundwater flow and contaminant transport. 3-D discrete fracture models were simulated and fracture flow analysis was performed and feasibility study on the water-curtain system was conducted through the fracture connectivity analysis in rock mass. As results of those analyses, it was interpreted that the leachate would trespass on the LPG storage cavern area in 30 years from the proposed wate disposal site and the vertical water-curtain system was effective mathod for the prevention of leachate's migration further into the cavern area.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2007.05a
• /
• pp.264-268
• /
• 2007

• Journal of Radiation Protection and Research
• /
• v.27 no.1
• /
• pp.67-75
• /
• 2002

The groundwater flow and contaminant transport numerical models have been established for understanding the movement of pollutants in surface soil environment. The numerical solutions were compared with the analytic solutions for the verification and the application of the models. The numerical solutions from the groundwater and transport models agreed welt with analytic solutions. Especially, the results of groundwater flow model were validated in one- and two-dimensional heterogeneous media. Therefore, it will represent well the characteristics of the heterogeneous media in the field applications. Also, the phenomena of the pollutant dispersion represented quite well by the advection and the hydrodynamic dispersion in the results of the transport model. The important input factor is the choice of complicated boundary conditions in operating the numerical models. The numerical results are influenced by the choice of the proper boundary conditions.

• Journal of the Korean Society of Groundwater Environment
• /
• v.5 no.2
• /
• pp.80-87
• /
• 1998

Since groundwater flow paths have one of the major roles to transport the radioactive nuclides from the radioactive waste repository to the biosphere, the discrete fracture network model is used for the rock block scale flow instead of the porous continuum model. This study aims to construct a three dimensional discrete fracture network to interpret the groundwater flow system in the study site. The modeling work includes the determination of the probabilistic distribution function from the fracture geometric and hydraulic parameters, three dimensional fracture modeling and model calibration. The results of the constant pressure tests performed in a fixed interval length at boreholes indicate that the flow dimension around boreholes shows mainly radial to spherical flow pattern. The fracture transmissivity value calculated by Cubic law is 6.12${\times}$10$\^$-7/ ㎡/sec with lognormal distribution. The conductive fracture intensity estimated by FracMan code is 1.73. Based on this intensity, the total number of conductive fractures are obtained as 3,080 in the rock block of 100 m${\times}$100 m${\times}$100 m.

• Tunnel and Underground Space
• /
• v.17 no.2 s.67
• /
• pp.109-118
• /
• 2007

The excavation damaged zone (EDZ) is an area around an excavation where in situ rock mass properties, stress condition. displacement. groundwater flow conditions have been altered due to the excavation. Various studies have been carried out on EDZ, but most studies have been focused on the mechanical bahavior of EDZ by in situ experiment. Even though the EDZ could potentially form a high permeable pathway of groundwater flow, only a few studies were performed on the analysis of groundwater flow in EDZ. In this study, the' hydraulic EDZ' was defined as the rock Lone adjacent to the excavation where the hydraulic aperture has been changed due to the excavation. And hydraulic EDZ (hydraulic aperture changed zone) estimated by two-dimensional DEM program was considered in three-dimensional DFN model. From this approach the groundwater flow characteristics corresponding to hydraulic aperture change were examined. Together. a parametric study was performed to examine the boundary conditions that frequently used in DFN analysis such as constant head or constant flux condition. According to the numerical analysis, hydraulic aperture change induced by the hydraulic-mechanical interaction becomes one of the most important factors Influencing the hydraulic behavior of jointed rock masses. And also from this study, we suggest the proper boundary condition in three-dimensional DFN model.

• Tunnel and Underground Space
• /
• v.19 no.3
• /
• pp.248-260
• /
• 2009

With regard to oversea mineral resources development, recent trend has been changed from a simple capital investment to a direct development of the resources. In relation to the stability of a slope in large open-pit coal mine, groundwater system was investigated and the validity of horizontal drainage hole was evaluated in Pasir coal mine, Indonesia. In this work, various field tests were carried out for a characterization of groundwater system, which included in-situ permeability measurement, tracer test and monitoring of groundwater levels. Especially, the influence of SM river on the characteristics of the groundwater flow system was mainly inspected. For the permeability measurement, Guelph permeameter was employed, and was found that sandstone was more permeable than mudstone and coal seam. From a comparison of lithological structure and the results of groundwater level monitoring, sandstone and thin coal seam with fractures were found to be a main channel for groundwater flow. In the results of tracer tests, the effect of SM river on the groundwater system depends on the geological structure of its base. To identify the effect of horizontal drainage holes, 2-D groundwater modeling was performed. Four different cases were tested, which are different from the length of drainage hole and the existence of pond on top of the slope. To enhance the drainage effect and slope stability, the drainage hole should be drilled to the depth of coal seam layer, which provides a main pathway of groundwater flow and embedded by sandstone. For this purpose, correct identification of surrounding geology should be preceded.

• Journal of Radiation Protection and Research
• /
• v.28 no.3
• /
• pp.155-163
• /
• 2003

The groundwater flow and contaminant transport numerical models have been established for analyzing the movements of pollutants in subsurface soil at Daeduk site. The groundwater flow and concentration of U-234 using the numerical models were simulated around Daeduk nuclear facilities. The computed groundwater flow was mainly advected toward the direction of east and southeast around HANARO in the site. The radioactive material entered into the subsurface soil was transported along the same direction with groundwater flow. The radioactive material deposited on the surface from the calculated concentration distributions was not affected by surrounding environment of the site.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.298-301
• /
• 2006

지하수 장해를 사전에 방지하고 지하수의 유동특성과 배경수질을 파악하기 위해 설치된 국가 지하수관측망에서는 지하수위, 전기전도도, 수온 항목을 주기적으로 측정하고 있으며 아울러 연 2회 생활용수 기준의 수질검사를 실시하고 있다. 이들 측정항목의 시간적 변화를 고찰함으로써 해당 지하수계의 이상 징후를 효과적으로 감지할 수 있다. 하지만, 이들 측정항목 만으로는 지하수의 수리화학적 환경을 제대로 파악하기가 어려우며, 따라서 지하수 수질 장해가 인지되었을 경우 그 원인을 효과적으로 규명하기가 쉽지 않다. 지하수 수질 장해는 인위적인 오염 외에도 지질 조건과 관련한 자연적 과정에 의해서도 빈번히 일어난다. 지하수 수질 장해의 원인과 지하수의 수질 변화 경향을 파악하기 위해서는 관측 항목에 추가하여 양/음이온 분석자료의 주기적 취득과 수리 지구화학적 해석이 필요하다. 금번 발표에서는 국가 지하수 관측망의 장기 관측 결과 지하수 수질 장해 우려지역으로 제안된 5개 지역의 수리지구화학 조사연구 사례를 소개한다. 관측망 관정 외에 주변 지역 지하수에 대한 양/음이온 분석을 수행하고 수리지구화학 해석을 수행함으로써 지하수 수질장해의 원인을 규명할 수 있었다.

• The Journal of Engineering Geology
• /
• v.11 no.1
• /
• pp.37-50
• /
• 2001

Through the modeting study on the groundwater now system around the underground stockpile site of crude oil near Seoul, we carried out the research on the influence of the groundwater yield near the site, the effect of the water curtain construction in order to reduce the influence of water yield, and the realized case study by measuring the water level change after the construction of the water curtain. For the simu1ation of the water yield and the water curtain, the nwnerical analysis code, MODFLOW has been utilized. Groundwater levels of the observation wells which were established to observe the hydraulic head around underground oil storage cavern of the study area have been changed in the range of from EL.+30 to +60 meter, while the simulation study revealed that groundwater levels changed in the range of from EL.+20 to +5Om. The hydrogeological condition of the underground oil storage cavern becomes stable by injection water to maintain the groundwater level around the cavern. The result shows the proper input of the hydrogeological factors helps the management to be effective for the oil stockpile site.