• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.194-202
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• 2009

The paper deals with the countermeasure against structure-borne noise source and noise reduction of drainage pipes. Recently, the problem the problem of the toilet drain noise of an apartment house has been become the center of public interest and a target of public grievance. Generally, the drain noise of a toilet in the apartment house has a pink noise characteristics below 2 kHz level, and therefore, the structure-borne noise has a great effect on the entire drain noise. In order to measure the transmission loss for various kinds of pipes such as PVC pipes, cast-iron pipes and newly developed AS pipes, experimental setup containing speakers as a sound source was designed and manufactured. The second-stories measurement room with a small size anechoic chamber was constructed and the noise level for different kinds of drainage pipes was measured by the sound level meter. Through the experimental research in the study, noise reduction capacity for various kinds of drainage pipes and countermeasures against structure-borne noise source are demonstrated.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.306-310
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• 2007

건물영향을 고려한 DEM기반 Dual-Drainage 도시침수해석모형은 배수시스템 해석 모형인 SWMM모형과 도시침수해석 모형인 DEM 기반 침수해석모형(이창희 등, 2006b)을 통합하고, 두 모형간의 유량의 전송과정을 수리학적 관계를 고려한 Dual-Drainage 도시침수해석모형(이창희 등, 2006c)에서 건물의 영향을 고려할 수 있도록 개발된 모형이다. 수치지도로부터 대상유역의 건물 데이터를 추출할 경우 이들 건물들은 매우 복잡하게 배치되어 있으므로 건물 모두를 다 고려하는 격자를 구성하는 것은 어려운 일이다. 그러므로, 건물들이 셀 내에 차지하는 비율을 구하여 침수지역 해석에 이용되었다. 본 모형을 통해 건물에 의한 점유면적 및 흐름의 방해 등으로 인하여 침수심 및 침수범위의 변화를 고려할 수 있으며, 건물 영향으로 인한 침수해석을 통해 침수유량의 도달 시간 및 시간별 침수범위를 보다 정확히 예측할 수 있다. 홍수 기간동안 지표침수유량 및 시간별 배수과정을 분석하여 범람수심 및 범람지역을 주요 시간대별로 계산하였고, 실측치인 침수흔적도와 비교함으로써 모형의 적용성을 검증하였다. 본 연구에서 개발된 침수해석 모형을 이용하여 최고침수위와 최고침수범위를 비교적 단시간에 효율적으로 계산함으로써 홍수피해와 투자액을 감안한 경제적인 배수시설의 결정을 위한 기본자료로 활용될 수 있으며, 국가 중요 시설물의 입지 선정, 주민의 보호 및 이동 등을 포함한 홍수피해의 판단자료로 이용될 수 있다.

• Journal of the Korean GEO-environmental Society
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• v.24 no.8
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• pp.5-11
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• 2023

Due to frequent occurrences of concentrated heavy rainfall caused by abnormal climate conditions in recent years, collapses of steep slopes have been occurring frequently due to surface erosion and increased pore water pressure. Various methods are being applied to prevent slope collapses, such as increasing the resistance to movement and reducing pore water pressure. Research on these methods has been consistently conducted as they provide an efficient response to slope collapses by satisfying both the conditions of resistance to movement and pore water pressure simultaneously. Therefore, in this study, we propose an upward slope reinforcement method by burying drainage materials with an upward slope inclination, instead of the conventional horizontal application. This approach aims to satisfy both slope reinforcement and drainage functions effectively, offering a comprehensive solution for slope stabilization. Furthermore, to determine the optimal burial angle that exhibits the most effective reinforcement and drainage effects of the proposed method, we investigated the reinforcement and drainage effects under conditions where the horizontal drainage materials were set at angles ranging from 0° to 60° in increments of 10° on a representative cross-section. Additionally, indoor model experiments were conducted under the conditions of 40°, which showed the most outstanding drainage effect, and 20°, which exhibited the highest safety factor, to validate the numerical analysis results. The results showed that the burial angle of 40° exhibits a relatively higher drainage effect as with the numerical analysis results, while the angle of 20° results in inadequate drainage and observed slope collapse.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.19
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• pp.32-38
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• 1975

In order to clarify the effect of underchannel drainage and culture on the ill-drainage paddy fields, the experiment was carried out at different amounts of fertilizer and planting space under the culvert. It had been found that the effect of underchannel drainage on the ill-drainage paddy field was very efficacious, and planting density was more effective on yield than the amount of fertilizer applied.

• Journal of the Korean Geotechnical Society
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• v.24 no.5
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• pp.99-106
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• 2008

This study is concernsed with the effect of a chimney drainage system installed at the back of reinforced soil block on preventing the pore water pressure development. A series of finite-element analyses based on transient seepage analysis were performed for a number of cases with different patterns of the chimney drainage system. The results were thoroughly analyzed to get insight into the mechanism of pore water pressure reduction effect of the chimney drainage system. It is shown that a vertical drainage system installed at the back of reinforced zone can be an effective means of maintaining the wall stability during rainfall by preventing pore pressure increase in the reinforced as well as the backfill zones. Also shown is that the optimum height of the chimney drain is 50% of the wall height. Practical implications of the findings were discussed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.20 no.2
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• pp.4695-4707
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• 1978

The objeative of this study is to study how to rapidly convert tidal land into cultivable land. The study of a rapid, reasonable desalinization method is conducted at Namyang tidal land which represents soil texture of tidal lands along the south west costa larea of Korea. Therefore, Researches were made at many Pilots in order to find a way of high efficiency of leaching with simpler facilities and cheaper costs. The results of study are briefly summarized as follaws: 1. Subdrainage efficieny is 35%. This is a Poorly drained area, and needs longer leaching desalinization period. 2. The efficieny of desalinization in P.V.C 16 meters plot is the same as that of mole drainage 2 meters plot. P.V.C 4 meters plot has desalinization effect as much as two times compared to P.V.C 16 meters plot. 3. Because the soil texture is silty-clay, desalinization in non-treated plot of sub-drainage and surface drainage desalinization take three times longer period in comparision with P.V.C 4 meters plot. 4. As to the desalinization rate of soluble salt in the soil, the efficieny of desalinization of the topsoil in P.V.C plots was 50% higher than that of mole drainage plot and about 170% higher than that of non-treated plot. In the deep soil salt accumulation at topsoil was observed in non-treated and mole drainage plots, but efficiency in P.V.C polt is about 40 times as high as that of mole drainage and non-treated plot. 5. As to the results of use gypsum and lime as sub-drainage soil improver, gypsum was 60% more efficieny than lime in the continuously inundated plot and 44% in the intermittently inundated plot. The efficieny of gypsum and lime in the intermittently flooded plot is 35% and 42% higher than that of continuously flooded plot reapeaticee1y.

• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.474-480
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• 2017

This study was to estimate the reduction effect of nonpoint source pollutants according to the rainfall intensity and drainage of infiltration grate inlet. Soil infiltration flow was measured on-site and SS load by the filter part was calculated by the experimental data in laboratory reactor test. Soil infiltration flow was measured to be about $1m^3/hr$ in soil condition saturated with water. The filter part of the infiltration grate inlet was a hydraulic equipment unhindered by soil infiltration on the bottom of the storage tank, because the infiltration flow was measured to be about $3m^3/hr$ continuously in the closing infiltration hole condition. Infiltration flow and SS load were over about $1m^3/hr$ and 1.71 kg according to laboratory results by the filter part using the artifical sample. Therefore, the above values could be presented as the limitted value to start the reduction of filtration effect. Reduction efficiencies of SS load by the filter part for the rainfall intensity were about 87 % at 5 mm/hr and about 61 % at 10 mm/hr in consideration of one infiltration grate inlet got the drainage area about $200m^2$. The reduction efficiency of nonpoint source pollutants was very effective in the first flush rainfall. However, the reduction efficiency by rainfall density was higher than by flow.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.6
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• pp.177-185
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• 2018

There is a need to study dust separator screens with good drainage efficiency while effectively filtering suspended solids and other contaminants entering the intake pumping station, the drainage pumping station and the mediation pumping station, the cooling water inlet of the power plant, and the like. In this paper, Numerical studies were conducted for the optimal design of the dust separator screen using the Coanda effect. The shape of the dust separator screen is important, such as the right curvature radius $R_1$ at the top of the dust separator screen and the left curvature radius $R_2$ at the top, h is the height difference and shape between the screen and the accelerating plate, and ${\theta}$ is the inclination angle of the screen. A total of 4 shape factors were set and the effects of Coanda and drainage performance of each element were compared and analyzed, the optimum length and size of each shape element were derived by classifying the shape elements into direct and indirect influences. Finally, it was possible to effectively filter foreign matter by narrowing the screen spacing, and the drainage performance was analyzed and optimized through numerical studies of dust separator screen.

• Journal of the Korean Geotechnical Society
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• v.23 no.6
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• pp.77-84
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• 2007

One of the most sensitive design specifications to be considered is infiltration and external pore-water pressures on underground structure construction. Development of pore-water pressure may accelerate leakage and consequently cause deterioration of the lining. In this paper, the development of pore-water pressure due to malfunctioning of drainage system and its potential effect on the linings are investigated using physical model tests. The deterioration procedure was simulated by controlling both permeability and flow rate. Development of pore-water pressure was monitored on the lining using pore pressure measurement cells. Test results identified the mechanism of pore-water pressure development on the tunnel lining. In addition, they showed that controlling flow rate is more effective method fur simulating deterioration procedure than permeability control. The laboratory model tests were reproduced using coupled numerical method, and showed that the effect of deterioration of drainage system can be theoretically expected using coupled numerical modeling method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.697-704
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• 1995

This experiment was carried out to elucidate the effect of the midsummer drainage times and some growth regulators on lodging characters, lodging and yield in puddled-soil drill seeding in rice. Dongjinbyeo, the mid-late maturing rice variety was seeded at May 11 by seeding machine with 4cm of furrow depth. Experimental plots were divided two main treatment without midsummer drain and two time drains (30 and 50 days after seeding), Inabenfide(IBF) was applied 40days before heading(DBH) and IBP was applied at 30DBH, respectively. Culm length was shorten, the wall of N$_4$ was thicken, and the breaking weight was increased at two time drainage and growth regulators applied in order of Inabenfide, IBP, and Control. Lodging wasn't occurred at two time drainage but it was occurred at none drainage in the order of Control, IBP, and Inabenfide applied. Yield was higher at two time drainage compared with none drainage and higher in order of Inabenfide, IBP and Control in none drainage but wasn't significantly different among growth regulators applied in two time drainage. Therefore, two times midsummer soil drying is recommendable management method for puddled -soil drill seeding of rice. Rice, Direct seeding, Puddled-soil, Drill seeding, Midsummer drainage, Growth regulator, Lodging.