• Proceedings of the Korean Radioactive Waste Society Conference
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• 2015.10a
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• pp.235-236
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• 2015

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.189-190
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• 2016

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

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.9 no.2
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• pp.37-48
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• 1991

In this study, conventional network adjustment and combined network adjustment methods for single network adjustment methods for single network and centric combination network were compared by the analysis of root mean square error and standard error ellipse of observed points. It can be concluded from this study that for conventional surveying methods, the accuracy is in theorder of trilateration, traverse and triangulation, and for the case of combined surveying method, the accuracy is in the order of multilateration surveying, combined traverse and combined triangulation-trilateration surveying. And when establishing new control points, the accuracy can be improved by increasing redundant observations of centric combination network instead of using the single network. Also, in case of combined traverse surveying by adding observable laterals, accuracy level of trilateration could be achieved, and it was found that traverse is effective for large areas where sighting is easy, and combined traverse surveying is effective for urban areas where sighting is difficult.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.159-166
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• 2010

The block-scale groundwater flow system at Olkiluoto site in Finland was simulated. The heterogeneous and anisotropic hydraulic conductivity field for the domain was constructed from the discrete fracture network, which considered only the fractured zones identified in the deep boreholes installed in the study site. The groundwater flow model was calibrated by adjusting the recharge rate and the transmissivities of the fractured zones to fit the calculated hydraulic heads and into- and out-flow rates in the observation intervals of the boreholes with the observed ones. In the calibrated model, the calculated flow rates at some intervals were not in accordance with the observed ones although the calculated hydraulic heads fit well with the observed ones, which revealed that the number of the conduits for groundwater flow is insufficient in the conceptual model for groundwater flow modeling. Therefore, it was recommended that the potential local conduits such as background fractures should be added to the present conceptual model.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.257-263
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• 2008

We analyzed the statistical properties for the conductive background fractures in the Low and Intermediate Level Waste(LILW) disposal site to conceptualize of its groundwater flow system. The background fractures were classified to fracture sets based on their trends and plunges that were obtained from the borehole logging data, and then the fracture transmissivity distribution was inferred from the fixed interval hydraulic test results. The fracture size distribution of each fracture set was estimated using the fracture density and fracture mapping data. To verify the analyzed results, we compared observed field data to simulated one from the DFN model that was constructed with the analyzed statistical properties of the background fractures, and they showed a good agreement.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.87-99
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• 2016

We present the results of two-dimensional numerical simulations predicting the flow of groundwater in a fractured unsaturated zone. We applied the k-field distribution of permeability derived from discrete fracture network (DFN) modeling as the hydraulic properties of a model domain. To model an unsaturated zone, we set the depth from the ground surface to the underground aquifer. The rate of water infiltration into the unsaturated zone was divided into two parts, an artificial structure surface and unsaturated soil zone. The movement of groundwater through the unsaturated zone was simulated with particular emphasis on contaminant transport. It was clearly observed that the contaminants dissolved in groundwater transported vertically from the ground surface to the saturated zone.

• The Journal of Engineering Geology
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• v.9 no.1
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• pp.31-43
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• 1999

This study aims to quantify the distribution characteristics of the fracture system for the numerical modeling of groundwater flow in the north-eastern area of Yosu peninsula. The study area is composed mainly of volcanic rocks and granite. The regional and site scale lineament in the range of magnitude Order 1 to Order 3 were analyzed from the geologic map, air-photograph and shaded relief map. The geometric parameter of Order 4 fracture system was acquired from the scanline survey on the ground surface. There is a similar trend in the preferred orientation between the regional lineament and the Order 4 fracture system except the Set 4 of Order 4 fracture system which is not prominent in the type. That is classified to three fracture sat of high dip angle and one of ow dip angle. From the lineament trend. The orientation of Order 4 fracture system has similar characteristics in each rock termination mode analysis, it is considered that the fracture system was developed systematically and sequentially from Set 1 to Set 4 Filling materials are distinct relatively in low dip angle set. The fracture spacing follows to lognoral distribution and the fracture frequency corrected by the modified Terzaghi correction ranges from 0.38 to 1.01 per mater in each fracture set. The fracture trace lenght also follows to lognormal distribution and ranges from 2.9m to 3.7m in each fracture set.

• 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.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.8 no.2
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• pp.35-43
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• 1990

In this paper a two dimensional network adjustment theory is developed to analyze the plane trilateration network of single triangle network, of quadrilateral network, of polygon trilateration network and of combined network. The characteristics of error were analysed by developing an error propagation equation for each form of plane trilateration network. In case of combined network, the result of error analysis was represented by error ellipses and gross error detection was carried out by data snooping method.