• 한국방재학회 논문집
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• 제6권4호통권23호
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• pp.29-36
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• 2006

최근 이상기후 및 집중호우로 인해 낙동강유역의 많은 지역이 재산 및 인명손실을 크게 입고 있으며 제방축조 재료의 획득 및 운송비등의 증가로 인해 재해방지차원의 제방축조에 여러 가지 어려움을 겪고 있는 실정이다. 본 연구에서는 낙동강 하상의 모래를 이용하여 소량의 시멘트를 혼합한 시멘트혼합토에 대해 삼축압축실험을 통해 시멘트혼합율에 따른 특성을 규명하고자 한다. 이를 위하여 낙동강유역 하상 모래와 시멘트의 혼합율을 변화시키면서 실내시험을 실시하였다. 제체재료의 적합성 검토, 설계 및 해석에 필요한 기초자료를 제공하기위해 다짐시험 및 표준삼축압축시험을 실시하여 시멘트혼합율에 따른 강도, 변형에 따른 응력 및 거동특성 등을 분석하였다.

• 환경영향평가
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• 제12권1호
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• pp.9-22
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• 2003

To consider environmental characteristics in the scope of geochemistry of streams, Hwasun area, soil, sediment and water samples near/in the streams were analyzed in texture and metal contents of soil and sediment and in quality in water. From those analyses, the soils are loamy sand, sandy loam, loam and silty loam in texture. And, the sediments are slightly gravelly sand, gravelly sand and gravelly muddy sand in facies. Metal contents in soils and sediments are of high near Hwasuneup and Hwasun coalfield. In peculiar, P, Co, Li, Ni, Zn and Pb exceed over crust mean contents. Physico-chemistry of above streams according to pH-Eh and Piper's diagrams indicates that the streams are, typically, assigned to natural river water. Water qualities of BOD, T-N and T-P in areas near Hwasun coalfield, Dongmyeon and Hwasuneup are polluted over V level. Enrichment factor(EF) representing metal condensation in P, Cu, Zn and Pb appear near Hwasun coalfield and Hwasuneup from the soil and sediment samples, in part. Additionally, river water in dry season is very high in BOD, T-N, $Na^+$ and ${SO_4}^{2-}$. It is suggested that the relatively high metal contents in the stream be connected with above coalfield and urban areas.

• 자원환경지질
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• 제7권3호
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• pp.87-100
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• 1974

This paper deals with grain size analysis, heavy mineral analysis and trace element analysis of the recent sediments of Han River basin between Cheongpyong, Gyeonggi province and Seoul. For each location the samples are taken at river shoreline, river berm and river dune. The size analysis discloses that the mean values range from $-1.37{\phi}$ to $-1.60{\phi}$, sorting values range from 0.25 to 1.84, skewness values range from -0.44 to 0.51 and kurtosis values range from -0.1 to 1.75. Based on the textural parameters, the dune sand can be distinguished from the shoreline-berm sand. The content of heavy minerals of each sample ranges from 0.04 to 4.7%. The principal heavy minerals are ilmenite, magnetite, leucoxene, garnet, amphibole, pyroxene, kyanite, zircon, monazite, tourmaline, epidote, limonite, and minor minerals are apatite, sillimanite, andalusite and olivine. In general, dune sand samples contain more heavy minerals than the samples of shoreline or berm sand. This suggests that the heavy mineral concentration is affected by wind action more than by any other causes. The content of ilmenite and leucoxene decreases, whereas the content of zircon and epidote increases as it approaches the downstream region. The differences result from the variance of geological occurrences. The emission spectrochemical analysis and colorimetry analysis revealed that the content of Ni and V in the heavy minerals of the study area are higher than those of other stream sediments in Korea. On the other hand the content of Cu, Ph, Zn, Mo, W, P, Mn, Cr, Ag and Sn are lower in the study area. It has been observed also that the contents of all the elements except for Bi are higher in this area than the samples of marine sediments of Yellow Sea.

• Environmental Engineering Research
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• 제22권2호
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• pp.203-209
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• 2017

Innovations in the biofiltration process can provide effective solutions to overcome crucial water pollution problems. The elimination of pollutants is a result of the combined effects of biological oxidation, adsorption and filtration processes. This research aims to evaluate the performance of quartz sand biofiltration for removing total suspended solids, turbidity, color, organic matter, and ammonium from polluted river water and develop an empirical model for designing quartz sand biofilters for the treatment of polluted river water. Experiments were conducted using two biofilter units filled with quartz sand as filter media. A set of experiments were performed to evaluate the effect of hydraulic retention time on biofilter performance in removing water contaminants. The kinetics of organic matter removal were also determined to describe the performance of the biofilter. The results show that biofiltration can significantly remove river water pollutants. Removal efficiency depends on the applied hydraulic retention time. At a hydraulic retention time of two hours, removal efficiencies of total organics, ammonium and total suspended solids were up to 78%, 82%, and 91%, respectively. A model for designing quartz sand biofiltration has been developed from the experimental data.

• 대한지리학회지
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• 제46권6호
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• pp.693-706
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• 2011

본 연구는 경상북도 영덕군 동해안의 송천 하구 사주를 대상으로, 지형의 형태적 특성과 형성 시기를 파악하고, 장기적 및 단기적인 하구 사주의 변화 과정과 원인을 분석하였다. 사주의 해안선 부근 모래는 남에서 북으로 갈수록 입도가 점차 감소하여, 파랑과 연안류가 대체로 북쪽으로 이동하는 경향이 강한 것으로 보인다. 하구 사주와 인근 해안사구 모래의 절대연대는 약 100년 이내로서 지형의 변화가 매우 심하였다. 하구 사주 내의 입수구는 1971년부터 1995년까지 사주의 남쪽에 위치하였으나, 1995년부터 현재까지는 사주의 북쪽이나 중앙에 나타나고 있는데, 그 원인은 2000년 이후 바람과 해류의 북류 경향이 뚜렷해지면서 파랑과 연안류의 이동 방향이 변화된 결과로 판단된다. 단기적으로 볼 때, 주로 9월부터 3월 사이에 파랑과 바람의 작용으로 퇴적작용이 우세하여 사주의 고도가 상승하고 면적이 넓어지며 지형 기복이 단순해지고, 입수구의 위치와 사주의 형태 변화가 크게 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.153-159
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• 1999

The objective of this study was to investigate the bond strength properties of antiwashout underwater concrete. The fine aggregate(river sand, blended sand (river sand : sea sand = 1 : 1), condition of cast and cure(sea water, fresh water), and compressive strength of proportion(210kgf/$\textrm{cm}^2$ ~ 330kgf/$\textrm{cm}^2$) were chosen as the experimental parameters. The experimental results show that the underwater segregation resistance was increased, but flowability (slump flow) and air contents were decreased as the compressive strength of proportion increased. Bond strength of antiwashout underwater concrete was similar to plain concrete. From this study, rational analytic formula for the modulus of rupture and bond stress are to be from compressive strength of concrete.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 추계 학술논문 발표대회
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• pp.121-122
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• 2016

Recently in the domestic construction industry, source depletion has resulted in instances of ready-mixed concrete companies using river sand or crushed sand with high fine particle content. But the use of such low-quality fine aggregate is known to cause concrete quality to decline and have negative effects. So this study analyzed how much of an impact changes in fine particle content have on cement mortar's engineering characteristics. As a result, the flow rate and air quantity, which are characteristics of unhardened mortar, were shown to decrease as fine particle content increased, and compression strength, a characteristic of light mortar, was shown to subtly increase as fine particle content decreased.

• 한국항만학회지
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• 제12권2호
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• pp.329-336
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• 1998

Sandmats are used to dissipate trapped water rapidly from the embankment built on marine soft ground. At present, however, it becomes difficult to obtain qualified sands since natural resources such as river sand are to exhausted. Also, low permeability of sand may cause low degree of consolidation and instability of embankment. In this study, design and construction methods was discussed. Drainage capacities of prefabricated horizontal drains which were installed in highway construction site are investigated in order to find possible substitution for river sands as drainage materials. On the basis of measurement data at the construction site, it was concluded that use of the prefabricated horizontal drains shows satisfactory drainage capacity without instability of embankment.

• 콘크리트학회논문집
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• 제18권4호
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• pp.459-467
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• 2006

최근 하천골재의 부존량 감소와 건설수요의 증가로 양질의 모래가 고갈되었고, 바닷모래와 같이 자연상태에서 얻을 수 있는 골재도 그 품질이 저급화되면서 골재의 품질에 대한 관심을 갖게 되었다. 따라서 잔골재를 바닷모래에만 지나치게 의존하고 있는 공급원의 편중을 다양화할 필요가 있으며, 바닷모래를 대체할 수 있는 골재원을 하루빨리 발굴할 필요가 있다. 한편 국내 건설현장에는 다양한 잔골재가 콘크리트에 사용되고 있으나, 이런 잔골재가 콘크리트에 미치는 영향에 대해 체계적으로 검토한 연구가 거의 없다. 따라서 본 연구에서는 최근 국내 건설현장에서 비교적 많이 사용되고 있는 잔골재가 콘크리트의 품질에 미치는 영향을 검토할 목적으로 잔골재 종류가 굳지 않은 콘크리트의 물성 및 경화된 콘크리트의 강도에 미치는 영향을 분석하였다. 그 결과, 부순모래는 바닷모래 및 강모래와 같은 천연골재에 비해 콘크리트의 유동성과 공기 연행성을 저하시키거나 블리딩을 증가시키고, 특히 입도 입형이 불량한 부순모래를 사용한 경우에는 더욱 콘크리트의 물성이 저하되는 것으로 나타났다. 그리고 W/C 55%, 45%에서 잔골재 종류가 강도에 미치는 영향은 거의 없으나, W/C 35%에서 부순모래는 천연골재에 비해 강도를 저하시키는 것으로 나타났다. 또한 입도 입형이 불량한 부순모래를 천연골재와 혼합하여 사용하는 경우에는 굳지 않은 콘크리트의 특성을 향상시키며, 강도에도 나쁜 영향을 미치지 않는 것으로 분석되었다.

• 자원환경지질
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• 제15권3호
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• pp.113-122
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• 1982

The surveyed Boseong river, flows from south to north crossing Boseong gun Mirukg myon, Nodong myon, Yuleo myon, Bocgnae myon, Mundeog myon, and Seungju gun Nam myon, Jeonranam do. The geology of the surveyed area consists of age-unknown composite gneiss and schist, crystaline chlorite gneiss, porphyroblastic gneiss and granite gneiss, and metasediments of Myon Bong formation and Seologri formation. These metamorphic rocks are intruded by cretaceous biotite granite, granodiorite, and quartz diorite. The heavy sands occur in Quarternary alluvium and colluvium. The composition of the river bed is sand 60%, gravel 30%, and clay 10%. The gravel content of the river bed decreases as the increases. The average depth of auger boring is 0.87 m. The average heavy mineral composition of the heavy sand is monazite 6.83%, zircon 4.88%, ilmenite 11.36%, magnetite 8.36% and garnet 4.84%. The best heavy minerals separation procedure would be primary treatment of the sand by humphrey spiral and table, and retreatment of the table concentrate by magnetic separator. The minimum economically feasible capacity of gravity and magnetic separation plant would be 500 ton/hr when only the heavy minerals are recovered but it may be reduced to 100 ton/hr. capacity, if gravels and sands are added to the valuable products.