• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.325-334
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• 2003

It is very difficult to rehabilitate the damaged earth dam core to manage it stably against development of flow path and increase of leakage by hydraulic fracture. In this study, application of CGS (Compaction Grouting System) to damaged earth dam core was noticed by analyzing and comparing the results of the in-situ data and FEM. Results of in-situ data showed that according as progress of rehabilitation works tip pressures increased and volume of injection decreased, voids of damaged dam core were filled with materials similar to origin dam core. Rehabilitations caused turbidity and volume of leakage to decrease at the same water level. Also, results of FEM analysis indicated that permeability decreased by rehabilitation. Through this study, it is proved that CGS is able to decrease permeability coefficient, volume of leakage and turbidity on damaged earth dam core.

• Journal of Korea Water Resources Association
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• v.48 no.3
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• pp.159-167
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• 2015

Low-level outlets are necessary to empty reservoir storage in case of emergency such as abrupt storage level rise due to storm, dam body inspection as well as initial reservoir storage filling. However, the Korean standard for low-level outlet should be complemented. In this study, the HEC-ResSim model is utilized to simulate and calculate the capacity of the outlets and the days of release in order to evacuate reservoir storage safely. Three cases are analyzed according to its capacity. As a large dam with more than $1,000{\times}106m^3$ total capacity, Soyanggang Dam is selected and as a medium dam between $100{\times}106m^3$ and $1,000{\times}106m^3$ total capacity, Habcheon Dam is selected. Finally as a small dam with a total capacity less than $100{\times}106m^3$, Daegok Dam is selected. The size of low-level outlet and days of storage evacuation is estimated and the applicability of the analysis method is studied.

• Geomechanics and Engineering
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• v.13 no.4
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• pp.685-699
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• 2017

In order to determine the rate of penetrability, water pressure test is used before the grouting. One of the parameters which have the highest effect is pressure. Mathematical modeling is used for the first time in this study to determine the optimum pressure. Thus, the joints that exist in the rock mass are simulated using cylindrical shell model. The joint surroundings are also modeled through Pasternak environment. In order to validate the modeling, pressure values obtained by the model were used in the sites of Seymareh and Aghbolagh dams and the relative error rates were measured considering the differences between calculated and actual pressures recorded in these operations. In water pressure test, in Seymareh dam, the error values were equal to 4.75, 3.93, 4.8 percent and in the Aghbolagh dam, were 22.43, 5.22, 2.6 percent and in grouting operation in Seymareh dam were equal to 9.09, 32.50, 21.98, 5.57, 29.61 percent and in the Aghbolagh dam were 2.96, 5.40, 4.32 percent. Due to differences in rheological properties of water and grout and based on the overall results, modeling in water pressure test is more accurate than grouting and this error in water pressure test is 7.28 percent and in grouting is 13.92 percent.

• Water for future
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• v.28 no.6
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• pp.169-181
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• 1995

No correction has been made for the rating curve of Goan Station since 1986 even though there has been a severe bed degradation until now. Furthermore, it was informed to Han River Flood Control Center that there was a difference between the discharge released from Paldang dam and the discharge observed at Goan station during 1990 flood. By considering such river bed changes, hydraulic model experiment with 1/100 scale was performed for the range of 2.2 km, which covers from Paldang dam to the downstream of Goan station. From this experiment, the rating curve was obtained by considering the discharges from Paldang dam and the corresponding water levels at Goan station. Also, the exsitingand the proposed rating curves were compared with those by computational method of RMA-2V.

• Ecology and Resilient Infrastructure
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• v.2 no.4
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• pp.317-323
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• 2015

This study investigated the impact of the morphological change on a physical fish habitat in the downstream reach of a dam using long-term mobile bed simulation. The quasi-steady model was used for hydraulic simulation and the habitat suitability index model was applied for physical habitat simulation. For simulating long-term morphological change of the stream bed, The Exner equation was used. Sorting of bed material was also considered. The results of simulation showed that erosion and armoring process occurred in a reach downstream of the dam and change of physical habitat for Zacco platypus followed. These results indicate that channel morphology and substrate conditions effected the physical habitat for considering long-term investigation.

• Journal of Korea Water Resources Association
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• v.42 no.5
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• pp.407-414
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• 2009

A quantitative analysis was conducted to study the impacts of artificial flow alteration on fish habitate condition change in the Geum River downstream the Daechung Multi-purpose Dam (DMD). River Analysis Package (RAP) was employed for the analysis and three fish species of black shiner, long nose barbel and Korean shinner were selected as icon species. The results of the analysis showed enhaced fish habitat conditions during low flow seasons in spring and fall after DMD construction, while the impact of the Youngdam Multipurpose Dam located upstream the DMD was insignificant. This result could be attributed to the fact that the increased flow during dry seasons helped create preferable habitat conditions for the fish species tested in this study.

• Geotechnical Engineering
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• v.12 no.1
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• pp.47-62
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• 1996

The bedding zone which influence directly to the safety of dam is supporting the face slab under hydraulic load in concrete faced rockfill dam. In case that leakage is developed due to various ruptured joint or cracks of face slab and etc., the bedding zone should limit the leakage by low permeability and keep the internal stability. In this study for the proper coefficient of permeability various properties, such as gradation, dry density, performance of embankment work and etc. were analysed. The results from the large scale test of permeability and density are summerized as follows : 1. Coefficient of permeability is decreased clearly by increase of dry density. 2. The particles smaller than the No.4 strive( p,) greatly influences the permeability under dry density of 2.24t 1 m3. 3. In case of C.40 and p,40%, even if dry density decreased to 2.0t/m3, the permeability coefficient is assumed to u x1-scm/s and internal stability is abtained. 4. Generally in dam construction since dry density and uniformity coefficient of bedding zone were higher than 2.2t/m3 and 50 respectively p, of 30~40% is assumed to be suitable and permeability coefficient of below 1$\times$10-3cm l s is expectable.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.263-267
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• 2007

Even though Waterpower Generation as pollution-free has its own merit of contribution by supply of good quality electricity, due to the noise made at the time of its operation, a normal mutual communication among the workers and technicians engaging at the hydraulic turbine dynamo room is almost impossible, and since those finishing materials had been used mainly by reflection material, it is actual situation that when working for maintenance in the hydraulic turbine dynamo room, as counterpart's voice vibrates, its working efficiency is difficult to ensure. On such view point, this Research has conducted Psycho-acoustics Experiment about voice Definition using Auralizational Technique, on the object for the hydraulic turbine dynamo room that improved its acoustic performance by computer simulation. As the result of Study, it was known that the clearness of sound with regard to voice information transmission was apparently improved in all items than before improvement. Therefore, it is considering that these results would be utilized usefully when renovation on the hydraulic turbine dynamo room in the future.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.1
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• pp.48-53
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• 1997

The sand bar has developed at the junction of the Kum-ho River and Shin-ryoung River. The sediment transported from the Kumho River basin has decreased since the Youngchon Dam has been functioning. Sand bar and the vicinity of the bottleneck at the upstrem of Kumho River and Osu Island which is consisted of sand bar have inundated frequently. This study was carried out through the hydraulic model test to calibrate the hydraulic effect from removal of sand bar in the river and straightening the river course by land reclamation. The water level of river at the vicinity of bottleneck can be lowered as much as 0.40~0.7m when the sand bar is removed. When river is straightened the river course by land reclamation the water level can be lowered as half of removal of sand bar.

• Journal of Korea Water Resources Association
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• v.38 no.8 s.157
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• pp.675-689
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• 2005

In this paper, it was analyzed the variation of hydraulic characteristics through changing discharge at main channel and lateral channel and state of hydraulic structure at the natural channel junction by experiment. The experimental area is chosen at the channel junction of Nam-Han river and Pyeongchang river. The scale of the experiment is 1/200 in horizontal, and 1/66.7 in vortical, so the distoration rate is 3. From the experiment, the reduction effect of the water level is $12\%$ in the case of removing intank dam, and $5\%$ at the hydro-electronic dam removing case. Furthermore, in the case of two hydraulic structures removing, the reduction effect of water level is $18\%$ at the channel junction. Also, the stagnation zone, which is cased diminution of the channel at the junction, is decreasing through removing the structures.