• 대한환경공학회지
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• 제30권11호
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• pp.1075-1086
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• 2008

비위생 매립지의 단층형 복토시스템을 위한 산업부산물의 응용성과 적합성을 평가하기 위하여 건설폐기물, 석탄회, 폐석고(인산석고), 슬래그(고로, 제강)와 석분슬러지를 대상으로 연구하였다. 먼저 대상 산업부산물들의 다양한 물리화학적, 수리역학적 특성들이 조사되었다. 그리고 배치실험과 장기간 용출시험을 통하여 이들 산업부산물들의 환경안정성도 검토하였다. 뿐만 아니라, 대상 산업부산물들에 식물을 조성해 봄으로써 식생의 적응성도 평가해 보았다. 산업부산물들의 물리화학적 특성 분석결과, 연구대상인 산업부산물 대부분이 매립지 복토재로 적합한 것으로 나타났다. 특히 모든 연구대상 산업부산물들에서 폐기물관리법에서 규정한 유해한 무기원소 종들의 농도가 규제치를 초과하지 않은 것으로 조사되었다. 이와 더불어, 석분슬러지만 제외하고 그 외 모든 대상 물질들에서 토양환경보전법에서 규제하는 원소들의 농도가 기준치 이하로 검출되었다. 배치실험과 장기간 용출시험 결과로부터 석탄회와 건설폐기물이 고려한 산업부산물들 중에서 매립지 복토재로서 가장 적합한 것으로 선정되었다. 식물 육종실험 결과, 석탄회가 가장 빠른 발아와 가장 큰 생육지표를 보여서 매립지 복토재로 이용될 경우 식생 조성에서 가장 효과적일 것으로 평가되었다. 일반토사와 석탄회로 혼합된 최종복토시스템에서 최적의 축분퇴비 시비는 헥타르당 40$\sim$50톤인 것으로 조사되었다.

• 콘크리트학회논문집
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• 제14권6호
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• pp.851-863
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• 2002

철근의 부식에 의해 발생하는 부식생성물은 부피팽창으로 인하여 주위의 콘크리트에 압력을 가한다. 이 팽창압은 철근 주의의 콘크리트에 인장응력이 생기게 하며 결국 콘크리트의 피복에 균열을 발생시킨다. 콘크리트 피복의 균열발생은 콘크리트 구조물의 사용수명을 감소시킬 뿐만 아니라 안전성에도 영향을 미친다. 본 연구의 목적은 콘크리트 피복에 균열을 일으키는 임계부식량을 조사하는 것이다. 이를 위하여 포괄적인 실험 및 이론적 연구를 수행하였다. 주요 실험변수로는 콘크리트의 강도와 피복두께이고 부식량의 증가에 따른 콘크리트 피복 표면의 인장변형률을 측정하였다. 철근 팽창에 의한 팽창압의 계산에 공극 및 균열 속으로 흡수되는 부식생성물을 고려하였다. 본 연구를 통하여 균열을 일으키는 임계부식량은 콘크리트 압축강도가 커짐에 따라 증가한다는 사실을 확인하였다. 부식층 내의 팽창압과 변형 사이의 관계를 유도하였으며 부식생성물층의 강성을 결정하였다. 팽창압과 변형 사이의 관계를 설명하기 위하여 압력을 유발하지 않는 변형량의 개념을 도입하였다. 본 연구에서 제안된 이론은 실험결과와 잘 일치하며 콘크리트 구조물의 내구성 설계에 기초가 될 수 있을 것이다.

• 한국환경과학회지
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• 제23권1호
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• pp.39-46
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• 2014

This study surveyed Abies koreana to identify the correlation between its vegetation structure according to its slope direction and seedling establishment in a bid to build basic research data on the changes and conservation of the A. koreana in Hallasan Mountain. The findings of its vegetation structure revealed that in both areas, Importance value was given to the A. koreana for its tree layer, the Taxus cuspidata for its shrub layer, and the Sasa quelpaertensis for its herb layer. However, in the Youngsil area with the tree layer, high importance was given to deciduous broad-leaved trees such as Prunus maximowiczii, Quercus mongolica, and the young species of the A. koreana in the shrub layer that can maintain the A. koreana forest's greater importance in the Jindallebat than in the Youngsil. Thus, the A. koreana forest in the Jindallebat is believed to lastlonger. The findings of correlation between the quantity of seedlings and their location by area revealed that in each tiny quadrat, the A. koreana seedling averaged 5.3 in the Youngsil and 2.9 in the Jindallebat. Both areas were all found to have a positive correlation in terms of rock exposure ratio and dead tree ratio as well as a negative correlation with regard to the cover degree of S. quelpaertensis, the canopy gap, the total vegetation, and the herb layer. It was found that the cover degree of the herb layer in the Youngsil and the S. quelpaertensis in the Jindallebat had the largest impact on the A. koreana seedlings.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권1호
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• pp.1-5
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• 2016

Capillary barriers, consisting of relatively fine-over-coarse materials, have been suggested as an alternative to traditional compacted soil covers. So, We were analysed to capillary barrier effect according to five cases of multi-layer cover systems. Water balance simulation was conducted with unsaturated flow model HELP to assess unsaturated hydraulic parameters such as hydraulic conductivity, climate affecting the performance of capillary barriers. Simulation were conducted for 5 Cases in the Ulsan area. Result of simulation indicated that three cases was formed unsaturated condition and capillary barrier effect.

• Advances in concrete construction
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• 제12권6호
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• pp.517-525
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• 2021

More underground structures are increasingly being constructed such as box culverts for electric power transmission, and the life extension of these structures is very important. It is well known that the steel embedded in concrete is usually invulnerable to corrosion because the high alkalinity of the pore solution in concrete generates a thin protective oxide layer on the surface of the steel. Recent observations in the field and experimental evidence have shown that even steel in concrete can be corroded through the carbonation reaction of cover concrete. Carbonation-induced corrosion in concrete may often occur in a high carbon dioxide environment. In this study, the risk of carbonation of underground box culverts in Korea was evaluated by measuring the car¬bonation rate and concrete cover depth in the field. Then, the carbonation-free service life for the cover depth of the steel was calcu¬lated with in situ information and Monte Carlo simulation. Additionally, an accelerated carbonation test for a cracked beam specimen was performed, and the effect of a crack on the service life of a box culvert was numerically investigated with Monte Carlo simulation based on experimental results.

• 한국지반환경공학회 논문집
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• 제7권1호
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• pp.29-39
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• 2006

최근 우리나라는 산업화와 현대화 및 인구의 증가와 더불어 과학기술의 발전은 주목할만한 수준에 이르렀다. 특히 과학기술에 의한 급속한 성장으로 인해 부가적으로 쓰레기 매립지의 설치에 대한 부담을 가중시키고 있다. 본 연구는 동결/융해하는 동안 매립층의 거동에 대한 기본적인 지식을 제공하고 문제점을 명백히 규명하는데 있다. 본 연구를 위하여 현장의 매립지와 유사한 기후조건 및 경계조건, 강우조건 등을 재현하는 대형 실내모형장비를 사용하였다. 점토와 시멘트, 무기물 광물을 혼합하여 제작된 고화처리층은 지지력을 목적으로 하는 45cm의 고화토층과 차수를 목적으로 하는 30cm의 불투수층의 $P_A$와 $P_B$층으로 구성되었으며 고화처리층 하부에는 30cm의 지하수 배제층, 상부에는 60cm의 침출수 집배수층으로 설계하였다.

• Structural Engineering and Mechanics
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• 제50권4호
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• pp.471-486
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• 2014

The number of explosive attacks on civilian structures has recently increased. Protection of structure subjected to blast load remains quite sophisticated to predict. The use of the pyramid cover system (PCS) to strengthen sandwich structures against a blast terror has great interests from engineering experts in structural retrofitting. The sandwich steel structure performance under the impact of blast wave effect is highlighted. A 3-D numerical model is proposed to study the PCS layer to strengthen sandwich steel structures using finite element analysis (FEA). Hexagonal core sandwich (XCS) steel panels are used to study structural retrofitting using the PCS layer. Field blast test is conducted. The study presents a comparison between the results obtained by both the field blast test and the FEA to validate the accuracy of the 3-D finite element model. The effects are expressed in terms of displacement-time history of the sandwich steel panels and pressure-time history effect on the sandwich steel panels as the explosive wave propagates. The results obtained by the field blast test have a good agreement with those obtained by the numerical model. The PCS layer improves the sandwich steel panel performance under impact of detonating different TNT explosive charges.

• 한국주거학회논문집
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• 제17권5호
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• pp.47-54
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• 2006

This study aims to evaluate the sound insulation performance of Korean traditional paper(Hanji) windows as a material of environmental friendly building. Six types of traditional windows with 4 types of traditional window positions, were installed in l/2.5 scale model house. And then according to KS F 2235, comparative sound level differences between outdoor and indoor were measured. The main results are as follows; 1) TL(Transmission Loss) of Korean traditional paper windows, which cover one eighth of total balcony window, are ranged from 15 to 19 dB(A) in the living room and from 8 to 11 dB(A) in the balcony space. 2) TL of Korean traditional paper windows, which cover one fourth of total balcony window, are ranged from 10 to 19 dB(A) in the living room and from 8 to 10 dB(A) in the balcony space. 3) TL of Korean traditional windows with one side-one layer paper is ranged from 10 to 21 dB(A) and two side-one layer paper is 15 to 23 dB(A) and two side-two layer paper is 19 to 23 dB(A) respectively.

• 한국지반공학회논문집
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• 제18권2호
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• pp.5-12
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• 2002

본 연구에서는 연약지반 상에 축조되는 고속철도 노반을 보강하기 위해 사용된 지오셀의 효과를 평가하기 위해 다양한 현장 평판재하시험과 동적 모형토조시험을 수행하였다. 실험결과로부터 지오셀 사용에 의한 보강노반의 두께 감소효과와 노상 지지력 증가효과가 평가되었다. 지오셀 1층과 복토 loom를 사용하면 동일한 두에의 쇄석층을 사용할 경우와 비교하여 3~4배의 지지력 개선효과가 있으며, 노반두께를 약 35cm 정도 감소시킬 수 있는 것으로 평가되었다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.57-57
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• 2018

The electrorefining process is generally composed of two recovery steps in pyroprocessing - the deposit of uranium onto a solid cathode and the recovery of the remaining uranium and TRU elements simultaneously by a liquid cadmium cathode. The liquid cathode processing is necessary to separate cadmium from the actinide elements since the actinide deposits are dissolved or precipitated in a liquid cathode. Distillation process was employed for the cathode processing. It is very important to avoid a splattering of cadmium during evaporation due to the high vapor pressure. In this study, a multi-layer porous round cover was proposed and examined to develop a splatter shield for the Cd distillation crucible. Cadmium vapor can be released through the holes of the shield, whereas liquid drops can be collected in the multiple hemisphere. The collected drops flow on the round surface of the cover and flow down into the crucible. The crucible cover was fabricated and tested in the Cd distiller. The cover was made with three stainless steel round plates with a diameter of 33.50 mm. The distance between the hemispheres and the diameter of the holes are 10 and 1 mm, respectively. About 40 grams of Cd and about 4 grams of Bi was distilled at a reduced pressure for two hours at $470^{\circ}C$. After the Cd distillation experiment, cadmium was not detected and more than 90 % of Bi remained in the ICP-OES analysis. Therefore the crucible cover can be a candidate for the splatter shield of the Cd distillation crucible. Further development of the crucible cover is necessary for the decision of the optimum cover geometry and the operating conditions of the Cd distiller.