• 한국지반공학회지:지반
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• 제14권1호
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• pp.59-70
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• 1998

국내 해안에 퇴적된 실트질 모래와 hydraulic fill한 지반에서 채취한 시료의 액상화 강도 측정을 위해 응력제어 진동삼축압축시험을 수행하였다. 이를 위해 1) 불교란시료와 교란시료의 액상화 강도 산정과 2) 등방 압밀된 시료와 비등방 압밀된 시료의 반복삼축시험결과 비교, 3) 본 시험결과와 국내 다른 시험자료 및 외국의 결과를 비교하였다. 등방 압밀 시료의 액상화 강도는 시료의 상대밀도에 따라 나타내었다. 실트질 함유량이 30%이하의 경우 액상화 강도는 실트질 영향을 거의 받지 않음이 나타났다. 비등방 압밀된 시료의 액상화 강도는 수직응력을 구속응력으로 나눈 유효압밀비에 영향을 받는다. 본 연구의 시험결과 한국 서해안의 실트질 모래의 액상화 강도는 Seed and Pea cock(1971)가 제안한 범위에서 내에 있음을 알 수 있다.

• 수산해양교육연구
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• 제28권6호
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• pp.1662-1672
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• 2016

To address physicochemical factors of yellow clay for removing Cochlodinium polykrikoides blooms, the correlation of removal efficiency with mineralogical characteristics of yellow clay collected from various areas was surveyed. Yellow clay from different localities showed the wide range of chemical compositions $SiO_2$ : 43~71%, $Al_2O_3$ : 13~26%, $Fe_2O_3$ : 5~14%, MgO : 0.4~1.8%, $K_2O$ : 0.6~3.3%, L.O.I.(Loss of Ignition) : 4.5~15%. The mineral compositions of yellow clay were mainly consisted of quartz and feldspar including small amounts of kaolinite, chlorite, and Fe-oxides. The result of size analysis showed that $6{\Phi}(31{\sim}16{\mu}m)$ and $7{\Phi}(16{\sim}8{\mu}m)$ were dominated sizes. The zeta-potential were in the range of -4.1~-20.7mV(average -13.7). As increasing removal efficiency of C. polykrikoides, contents of $Al_2O_3$, $Fe_2O_3$ and L.O.I. in yellow clay increased, whereas $SiO_2$ content decreased. Furthermore, the amounts of silt mineral and small particle were high when the removal efficiency was high. According to factor analysis using principle component analysis, two components of factor 1 and factor 2 showed 79% of the total variance, which is related to cohesion and adsorption. Inducing cell lysis of C. polykrikoides by cohension and adsorption between C. polykrikoides and yellow clay.

• 한국토양비료학회지
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• 제49권3호
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• pp.235-241
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• 2016

The soil does not only serve as a medium for plant growth but also for engineering construction purposes. It is very weak in tension, very strong in compression and fails only by shearing. The behaviour of the soil under any form of loading and the interactions of the earth materials during and after any engineering construction work has a major influence on the success, economy and the safety of the work. Soils and their management have therefore become a broad social concern. A limitless variety of soil materials are encountered in both agronomy and engineering problems, varying from hard, dense, large pieces of rock through gravel, sand, silt and clay to organic deposits of soft compressible peat. All these materials may occur over a range of physical properties, such as water contents, texture, bulk density and strength of soils. Therefore, to deal properly with soils and soil materials in any case requires knowledge and understanding of these physical properties. The desired value of bulk density varies with the degree of stability required in construction. Bulk density is also used as an indicator of problems of root penetration,soil aeration and also water infiltration. This property is also used in foundation engineering problems. While not conforming to standard test procedures, this work attempts to add to the basic information on such important soil parameters as water content, bulk density.

• 한국토양비료학회지
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• 제49권5호
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• pp.548-554
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• 2016

Optimal range of soil physical quality to enhance crop productivity or to improve environmental health is still in dispute for the upland soil. We hypothesized that the optimal range might be established by comparing soil physical parameters and their interactions inhibiting crop growth. The parameter identifying optimal range covered favorable conditions of aeration, permeability and root extension. To establish soil physical standard two experiments were conducted as follows; 1) investigating interactions of bulk density and aeration porosity in the laboratory test and 2) determining effects of soil compaction and deep & conventional tillage on physical properties and crop growth in the field test. The crops were Perilla frutescens, Zea mays L., Solanum tuberosum L. and Secale cereael. The saturated hydraulic conductivity, bulk density from the root depth, root growth and stem length were obtained. Higher bulk density showed lower aeration porosity and hydraulic conductivity, and finer texture had lower threshold bulk density at 10% aeration bulk density. Reduced crop growth by subsoil compaction was higher in silt clay loam compared to other textures. Loam soil had better physical improvement in deep rotary tillage plot. Combined with results of the present studies, the soil physical quality was possibly assessed by bulk density index. Threshold subsoil bulk density as the upper value were $1.55Mg\;m^{-3}$ in sandy loam, $1.50Mg\;m^{-3}$ in loam and $1.45Mg\;m^{-3}$ in silty clay loam for optimal soil physical quality in upland.

• 한국토양비료학회지
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• 제49권5호
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• pp.434-439
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• 2016

Anthropogenic soil in cropland is formed in the process of subsoil reversal and the refill of soil into cropland. However, there was little information on the chemical properties within soil profiles in anthropogenic soil under rice paddy near the river. In this study, we investigated the chemical properties within soil profiles in the anthropogenic soil located at 4 sites in Gumi, Kimhae, Chungju, and Euiseong to compare with the natural paddy soil near the river. Among particle sizes, the sand content decreased under soil profiles but the silt and clay contents increased compared to the natural paddy soil in soil profiles. Organic matter content in topsoil of anthropogenic soil was lower than in that of natural soil, which was shown the contrary tendency within soil profiles. Also, the soil pH, available $P_2O_5$, and exchangeable cations were higher in anthropogenic soil compared to natural paddy soil at topsoil, which was maintained these tendency into soil depth. Nutrients may be equally distributed in anthropogenic soil during the process of refill in paddy soil near the river. This results indicated that anthropogenic soil would contribute to carbon sequestration, the mitigation of compaction, and reduction of fertilizer application in paddy soil. Therefore, characteristics of anthropogenic soil can be used for the soil management in cropland.

• 한국토양비료학회지
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• 제50권5호
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• pp.383-390
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• 2017

Heavy metal contamination of soil might be a cause of serious concern due to the potential health impacts of consuming contaminated products. In this study, the total content of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn, As, and Hg) in soils was analyzed, and the difference of heavy metal contents depending on crops, soil characteristics, and topography was compared in 169 greenhouse soils obtained from Gyeongnam Province. The concentrations of the heavy metals were $0.25mg\;kg^{-1}$ (ranged 0.01~0.44) for Cd, $28.94(0.53{\sim}72.63)mg\;kg^{-1}$ for Cr, $26.03(0.5{\sim}166.13)mg\;kg^{-1}$ for Cu, $14.91(1.27{\sim}33.22)mg\;kg^{-1}$ for Ni, $15.76(0.43{\sim}57.1)mg\;kg^{-1}$ for Pb, $119.72(6.33{\sim}239.39)mg\;kg^{-1}$ for Zn, $2.54(0.01{\sim}23.57)mg\;kg^{-1}$ for As, and $0.049(0.012{\sim}0.253)mg\;kg^{-1}$ for Hg in topsoils. The concentrations of Pb and As in topsoil were highest in green pepper and those of Cd, Cr, and Ni were highest in melon. In addition, the concentrations of Cr and Ni were highest in diluvial terrace compared with the other topographies. Higher concentrations of Cd, Cr, and Ni were found in silty clay loam and silt loam soils than sandy loam and loam soils.

• 한국수자원학회논문집
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• 제47권1호
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• pp.63-70
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• 2014

본 연구에서는 가평천을 대상으로 저서성 대형무척추동물 서식처의 수리 특성을 조사하였다. 각각의 무리들 중에서 대표적인 종은, 붙는 무리는 두점하루살이, 헤엄치는 무리는 두갈래하루살이, 굴파는 무리는 깔따구, 기는 무리는 바수염날 도래이었다. 저서성 대형무척추동물은 유속과 수심, 하상의 재료 등 하천의 수리학적 특성에 따라 다른 종류의 무리들이 서식하는 것으로 관찰되었다. 헤엄치는 무리는 수심이나 하상 재료보다는 주로 유속에 의하여 그 서식 상태가 결정되었고, 0.15~0.36 m/s에서 서식하였다. 굴파는 무리는 하상 재료가 모래나 실트인 곳을 선호하고 하상 또는 바로 상부에서 서식하였다. 기는 무리는 하상 재료가 주로 자갈이나 호박돌인 곳을 선호하고 유속이 0.05~0.15 m/s에서 서식하였다. 붙는 무리는 하상재료가 조약돌이나 자갈인 곳을 선호하고 유속이 0.06~0.15 m/s에서 서식하였다. 각 무리별 서식처의 수리 특성이 달라지지만, 일반적으로 저서성 대형 무척추동물은 유속에 의해 서식 상태가 달라진다는 것을 알 수 있었다.

• 한국지반공학회논문집
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• 제28권9호
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• pp.97-106
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• 2012

본 논문에서는 혼합토의 역학적 특성을 해명하기 위한 기초연구로 모래와 비소성 실트로 구성된 혼합토를 대상으로 모래가 골격구조의 주체를 이루는 범위 안에서 다양한 세립분함유율로 조성된 공시체를 제작하였다. 모래입자의 파쇄가 발생하는 고압영역의 등방압축실험을 수행하기 위하여 고압삼축시험기를 이용하여 혼합토의 압축특성 및 파쇄에 대한 영향을 조사했다. 시험 결과, 모래의 압축특성은 입자파쇄가 발생함에 따라 항복에 도달한 뒤에는 1개의 NCL에 수렴하는 경향을 나타낸다. 한편, 혼합토의 압축특성은 세립분함유율이 증가함에 따라 조립자가 세립분에 의해 둘러싸여 쿠션작용에 의해, 조립자가 파쇄를 일으키기 어려워지므로 압축곡선의 최대경사가 완만해지고 항복응력 또한 증가함을 알 수 있다.

• 한국환경과학회지
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• 제8권5호
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• pp.593-600
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• 1999

In order to determine the changes of sediment facies and metal levels in surface sediments after the construction of Shiwha Lake, surface sediments were sampled at 8 sites located on the main channel monthly from June, 1995 to August, 1996 and analysed for 12 metals (Al, Fe, Mn, V, Cr, Co, Ni, Cu, Zn, Cd, As and Pb) by ICP/AES and ICP/MS. Two groups of sampling sites(the inner lake with 3 sites and the outer lake with 5 sites) are subdivided by the surface morphology ; the inner lake is a shallow channel area with a gentle slope, while the outer lake is relatively deep and wide channel with a steep slope which has many small distributaries. After the construction of dam, fine terrestrial materials were deposited near the outer lake, which resulted in the change of major sediment facies from sandy silt to mud. With the deposition of fine sediments in the outer lake, anoxic water column induced the formation of sulfide compounds with Cu, Cd, Zn and part of Pb. Metal (Cr, Ni, Cu, Zn and Cd) contents in sediments increased up to twice within 2 years after the construction of dam. This is due to the direct input of industrial and municipal wastes into the lake and the accumulation of metals within the lake. In addition, frequent resuspension of contaminated sediments in a shallow part of the lake may make metal-enriched materials transport near the outer lake with fine terrestrial materials. As the enrichment of Cu, Zn, Cd and part of Pb in the Shiwha Lake may be related to the formation of unstable sulfide compounds by sulfate reduction in anoxic water or sediment column, the effect of mixing with open coastal seawater is discussed.

• 한국지구과학회지
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• 제27권3호
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• pp.328-340
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• 2006

강화도 장화리 니질 조간대의 계절 변화에 따른 지형 변화와 퇴적 환경을 알기 위해서 4개 측선의 지형 변화, 112점의 표층 퇴적물 그리고 2점의 주상 퇴적물을 얻어 퇴적학적 분석과 방사선 동위원소 분석을 수행하였다. 표층 퇴적물은 크게 4가지의 퇴적상 즉, 사질, 니질 사, 사질 니, 실트로 나누어졌다. 장화리 조간대는 겨울철로 갈수록 표층 퇴적상이 조립해지고, 조간대 경사가 급해지는 등 전형적인 계절적 변화가 나타났다. 주상퇴적물에서 전체적인 퇴적상은 실트가 우세하고 분급은 불량하였다. Pb-210 동위원소를 분석한 결과 강화도 조간대의 평균 퇴적속도는 약 5 mm/yr로 나타났다. 또한 주상시료 최상부 퇴적상의 차이는 최근 이 연구 지역의 급격한 퇴적환경 변화를 지시하며, 이는 최근 주변 해역의 대규모 연안 개발 사업과 연관되어있는 것으로 사료된다.