• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.533-537
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• 2004

The erodibility of soil is an important factor to scour, especially in fine-grained soils. In this study, the erosion characteristics of kaolinite are quantified through the scour rate tests using the Erosion Function Apparatus called EFA. The basic soil property tests are also performed. The kaolinite samples are prepared by mixing with distilled water and formed to the designed maximum consolidation pressure of 60, 110, 160, 240, 360kPa, respectively. The results of the scour rate tests are presented in a format of a plot showing the relationship between erosion rates and shear stresses. Erosion properties of kaolinite showed a striking contrast according to the maximum consolidation pressure, and a correlation was established between the erosion properties of kaolinite and the soil properties; water content, undrained shear strength, dry density.

• Corrosion Science and Technology
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• 제12권4호
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• pp.179-184
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• 2013

Pipe wall thinning caused by erosion and corrosion can adversely affect the operation of aged nuclear power plants. Some injured workers owing to pipe rupture has been reported and power reduction caused by unexpected pipe damage has been occurred consistently. Therefore, it is important to develop erosion-corrosion damage prediction model and investigate its mechanisms. Especially, liquid droplet impingement erosion(LDIE) is regarded as the main issue of pipe wall thinning management. To investigate LDIE mechanism with corrosion environment, we developed erosion-corrosion damage simulation apparatus and its capability has been verified through the preliminary damage experiment of 6061-Al alloy. The apparatus design has been based on ASTM standard test method, G73-10, that use high-speed rotator and enable to simulate water hammering and droplet impingement. The preliminary test results showed mass loss of 3.2% in conditions of peripheral speed of 110m/s, droplet size of 1mm-diameter, and accumulated time of 3 hours. In this study, the apparatus design revealed feasibility of LDIE damage simulation and provided possibility of accelerated erosion-corrosion damage test by controlling water chemistry.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.593-596
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• 2008

The scour phenomenon involves the erosive potential of flowing water and the relative ability of the soil to resist erosion. The scour phenomenon in cohesive soils is much different from that in non-cohesive soils. Granular soils resist erosion by their buoyant weight and the friction between the particles. The soil particles are dislodged individually from the bed under the action of the eroding fluid. Scour in cohesive soils is much slower and more dependent on soil properties than that in non-cohesive soils. Therefore the analysis models for estimating erosion characteristics of cohesive soils should consider not only flowing water but also the relative ability of the soil to resist erosion. In this study, erosion characteristics for the clay-silt mixed soil will be analyzed as a fundamental study for development of bridge scour analysis and design system considering scour resistance capacity of a soil. For this analysis, the relationship between scour characteristics and soil properties was evaluated through scour rate test with Kaolinite samples remolded using various loading and contents of silt.

• 한국산림과학회지
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• 제108권3호
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• pp.329-340
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• 2019

불투과형 사방댐에 의한 수질오염 문제는 산림유역관리에 있어 매우 중요하지만, 이에 대한 신뢰할 수 있는 연구는 상대적으로 부족하다. 이 연구에서는 이를 위하여 낙동강유역 사방댐을 대상으로 계류수와 저류수의 수질을 조사하였으며, 수질 특성과 유역의 물리적 환경과의 상관관계를 분석하였다. 전체 43개의 조사대상 사방댐 중에서 농업용수 등급이하로 판정된 곳은 10%미만으로 나타나 전반적으로 수질은 양호하였다. 계류수 및 저류수에서 공통적으로 상관성이 높게 나타난 항목은 TOC와 산소요구량, SS와 탁도, SS와 Chl-a, Chl-a와 탁도 등이었다. 계류수에서 높은 상관성을 보인 항목들은 BOD와 SS, BOD와 Chl-a, BOD와 탁도, TOC와 Chl-a 등이었다. 이 연구의 결론은 사방댐 저류수의 수질이 대부분 양호하였고 저류수 수질이 유출수 수질에 다소 영향이 있지만 개별 수질항목에 국한된다는 것이다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.337-337
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• 2020

기후, 지형, 토지이용 등 다양한 환경요인들의 조건에 따라 동일한 강수량에도 표토침식량이 다르게 발생한다. 지형과 토지이용은 인위적인 개발에 의해 크게 변화될 수 있지만 인위적인 요소를 제외한다면, 지형변화는 매우 느리게 발생하며 토지이용은 계절적으로 변화하게 된다. 우리나라 대부분의 토양침식은 강우-유출에 의한 침식(water erosion)으로 지표를 흘러가는 유체에 함께 표토를 구성하는 토양 입자들이 이동하면서 발생하게 되는데 지표면을 덮고 있는 피복과 사면경사에 큰 영향을 받게 된다. 본 연구에서는 강우와 지표흐름을 고려할 수 있는 물리적 기반 토양침식모형을 이용하여 토지이용과 경사에 따라 토양침식량과 공간적 침식분포가 어떻게 변화되는지 분석하고자 하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.454-458
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• 2007

Nonpoint source (NPS) pollution is a serious problem causing the degradation of soil and water quality. Concentrated overland flow is the primary transport mechanism for a large amount of NPS pollutants from hillslope areas to downslope areas in a watershed. In this study, a soil erosion model, nLS model, to identify transitional overland flow regions (i.e., ephemeral gully head areas) was developed using the kinematic wave overland flow theory. Spatial data, including digital elevation models (DEMs), soil, and landcover, were used in the GIS-based model algorithm. The model was calibrated and validated using gully head locations in a large agricultural watershed, which were identified using 1-m aerial photography. The model performance was better than two previous approaches; the overall accuracy of the nLS model was 72 % to 87 % in one calibration subwatershed and the mean overall accuracy was 75 to 89 % in four validation subwatersheds, showing that the model well predicted potential transitional erosion areas at different watersheds. However, the user accuracy in calibration and validation was still low. To improve the user accuracy and study the effects of DEM resolution, finer resolution DEMs may be preferred because DEM grid is strongly sensitive to estimating model parameters. Information gained from this study can improve assessing soil erosion process due to concentrated overland flow as well as analyze the effect of microtopographic landscapes, such as riparian buffer areas, in NPS control.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1997-2002
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• 2007

본 연구에서는 유역내의 토양보존계획 및 관리를 위해 토사유실평가모델과 현장검토를 실시하여 대청호 유역의 토사유실 원인지역을 선정하였다. 먼저 DEM, 정밀토양도, 토지피복도 및 강우자료를 기반으로 RUSLE 모델을 이용하여 대청호 유역의 단위토사유실량을 평가하였다. 토사유실모델에서는 토사의 이동경로 및 작물종류를 고려하기 어렵기 때문에 다각적인 현장조사를 통해 토사유실 주요하천을 선정하는 것이 필요하다. 모델로 분석한 소유역별 원인지역을 검토하기 위해 현장조사를 실시한 결과, 대청호유역에서는 무주남 대천, 원당천, 금평천 등이 높은 토사유실량을 나타내었다. 현장조사 결과 이러한 지역들은 하천주변에서 경사가 급하고 작물의 재배조건도 토사유실에 취약한 것으로 분석되었다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.241-246
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• 2005

Doam watershed is located at alpine areas in the Kangwon province. The annual average precipitation, including snow accumulation during the winter, at the Doam watershed is significantly higher than other areas. Thus, pollutant laden runoff and sediment discharge from the alpine agricultural fields are causing water quality degradation at the Doam watershed. To estimate soil erosion from the agricultural fields, the Universal Soil Loss Equation (USLE) has been widely used because of its simplicity to use. The USLE rainfall erosivity (R) factor is responsible for impacts of rainfall on soil erosion. Thus, use of constant R factor for the Doam watershed cannot reflect variations in precipitation patterns, consequently soil erosion estimation. In the early spring at the Doam watershed, the stream flow increases because of snow melt, which results in erosion of loosened soil experiencing freezing and thaw during the winter. However, the USLE model cannot consider the impacts on soil erosion of freezing and thaw of the soil. Also, it cannot simulate temporal changes in USLE input parameters. Thus, the Soil and Water Assessment Tool (SWAT) model was investigated for its applicability to estimate soil erosion at the Doam watershed, instead of the widely used USLE model. The SWAT hydrology and erosion/sediment components were validated after calibration of the hydrologic component. The $R^2$ and Nash-Sutcliffe coefficient values are higher enough, thus it was found the SWAT model can be efficiently used to simulate hydrology and sediment yield at the Doam watershed. The effects of snow melt on SWAT estimated stream flow and sediment were investigated using long-term precipitation and temperature data at the Doam watershed. It was found significant amount of flow and sediment in the spring are contributed by melting snow accumulated during the winter. Thus, it is recommend that the SWAT model capable of simulating snow melt and long-term weather data needs to be used in estimating soil erosion at alpine agricultural land instead of the USLE model for successful soil erosion management at the Doam watershed.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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• pp.66-73
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• 2017

Empirical erosion models like Universal Soil Loss Equation (USLE) models have been widely used to make spatially distributed soil erosion vulnerability maps. Even if the models detect vulnerable sites relatively well utilizing big data related to climate, geography, geology, land use, etc within study domains, they do not adequately describe the physical process of soil erosion on the ground surface caused by rainfall or overland flow. In other words, such models are still powerful tools to distinguish the erosion-prone areas at large scale, but physics-based models are necessary to better analyze soil erosion and deposition as well as the eroded particle transport. In this study a physics-based soil erosion modeling system was developed to produce both runoff and sediment yield time series at watershed scale and reflect them in the erosion and deposition maps. The developed modeling system consists of 3 sub-systems: rainfall pre-processor, geography pre-processor, and main modeling processor. For modeling system validation, we applied the system for various erosion cases, in particular, rainfall-runoff-sediment yield simulation and estimation of probable maximum sediment (PMS) correlated with probable maximum rainfall (PMP). The system provided acceptable performances of both applications.

• 대한기계학회논문집A
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• 제37권6호
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• pp.739-745
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• 2013

본 연구에서는 급수 순환 시스템 중 동작 유체의 이송을 위해 사용하는 배관을 대상으로 관로 크기 및 고온 급수 환경에 따른 침식-부식 거동과 그 영향을 규명하고자 하였다. 이를 위해 일반적인 관로 소재인 철과 핵심 부식 인자인 산소의 화학반응식을 기반으로 Hayduk 과 Minhas 가 제안한 모델을 이용하여 침식-부식 해석을 실시하였다. 상용 유한요소해석 프로그램인 ABAQUS 를 사용하여 해석을 수행하였으며 배관의 직경 및 급수 온도를 변화시킴에 따른 침식-부식률을 평가할 수 있었다. 결과를 통해 급수 온도가 침식-부식률에 가장 큰 영향을 미치는 요인이 됨을 알 수 있었으며, 특히 $290^{\circ}C$ 급수에 노출된 스테인리스 316 강은 연간 $2.59{\mu}m$의 두께 손실이 발생할 것으로 예상되었다.