• 한국지하수토양환경학회지:지하수토양환경
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• 제23권3호
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• pp.27-42
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• 2018

It is important to identify the contaminant sources and to evaluate the fate and transport of heavy metals to crops in agricultural lands. This study was conducted to evaluate metal sources and its transfer and accumulation to crop in agricultural soils. Pollution indices were calculated and multivariate analysis was performed to identify metal sources. To evaluate transfer and accumulation of metals to crops, the contents of phytoavailable metals were evaluated by using single extraction method and the correlation between metal content and soil properties was analyzed. Also the BCF was quantitatively evaluated for investigating the metal transition to each crop grown in the research area. As a result, Cr, Ni, and Co were expected to be mainly derived from geologic factors due to weathering of certain parent rocks. The content of nickel in soils of the research area was slightly higher than that of the concern level criteria based on total concentration, but the amount transferred and accumulated in the crops was actually low. Understanding the contamination characteristics by investigating the pollution sources of heavy metals and its transfer and accumulation to crops through various evaluation techniques could provide important information for proper management of the agricultural land.

• 한국지반공학회논문집
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• 제16권4호
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• pp.171-181
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• 2000

성토지지말뚝 상부의 성토지반내에서 발생되는 지반아칭효과에 의하여 성토하중이 말뚝에 전달되는 효과를 조사하면서 제안된 이론해석의 신뢰성을 확인하기 위하여 일련의 모형실험을 수행하였다. 본 모형실험에서 말뚝은 성토 아래에 일렬로 수열의 줄말뚝으로 설치하였으며, 말뚝캡보는 성토의 길이방향에 직각방향으로 말뚝두부에 설치하였다. 성토재의 하중전달에 가장 큰 영향을 미치는 요인으로는 말뚝캡보사이의 간격과 성토고를 들 수 있다. 이전의 이론적인 연구에 의해 제안된 지반아치의 반경보다 약 33%정도 큰 최소소요성토고보다 높게 성토를 실시할 경우 지반아치는 완벽하게 발생될 뿐만 아니라, 실험치와 이론치는 잘 일치함을 모형실험결과 확인할 수 있다. 모형말뚝캡보에 작용하는 성토하중의 분담률은 말뚝캡보사이의 간격이 증가함에 따라 감소하는 반면, 성토고가 높아짐에 따라 증가하였다. 따라서, 설계시 말뚝의 성토하중지지효과를 극대화시키기 위해서는 성토고를 충분히 높게한 상태에서 말뚝캡보의 간격비를 감소시켜야 한다. 여기서 말뚝캡보의 간격비를 감소시키려면 말뚝캡보사이의 간격을 감소시키거나 말뚝캡보의 폭을 증가시켜야 한다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 학술발표대회 논문집
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• pp.137-143
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• 1996

• Earthquakes and Structures
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• 제14권1호
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• pp.85-94
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• 2018

The paper focuses on the seismic responses of a hyperbolic cooling tower resting on soil foundation represented by the three-parameter Vlasov elastic soil model. The three-parameter soil model eliminates the necessity of field testing to determine soil parameters such as reaction modulus and shear parameter. These parameters are calculated using an iterative procedure depending on the soil surface vertical deformation profile in the model. The soil and tower system are modeled in SAP2000 structural analysis program using a computing tool coded in MATLAB. The tool provides a two-way data transfer between SAP2000 and MATLAB with the help of Open Application Programming Interface (OAPI) feature of SAP2000. The response spectrum analyses of the tower system with circular V-shaped supporting columns and annular raft foundation on elastic soil are conducted thanks to the coded tool. The shell and column forces and displacements are presented for different soil conditions and fixed raft base condition to investigate the effects of soil-structure interaction. Numerical results indicate that the flexibility of soil foundation leads to an increase in displacements but a decrease in shell membrane and column forces. Therefore, it can be stated that the consideration of soil-structure interaction in the seismic response analysis of the cooling tower system provides an economical design process.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.638-644
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• 1999

The objectives of the study are to investigate thermal conductivity(TC) and coefficient of thermal transmission (CTT) according to the type of soils, the presence of reinforceemnt, temperature, relative humidity and to analyze experimentally the characteristics of thermal transfer of reinforced soil wall. Results are summarized as follows ; 1) Clayey soil has high value of TC and CTT than sandy soil. 2) TC and CTT of reinforced soil wall is about 6∼17% higher than those of reinforced one, 3) It is founded that the effect of relative humidity on the soil wall is important at the same temperature and 4) As the temperature is high, it is appeared that TC and CTT are high.

• 대한원격탐사학회지
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• 제24권5호
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• pp.427-436
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• 2008

This paper presents radar remote sensing of soil moisture and surface roughness for vegetated surfaces. A precise volume scattering model for a vegetated surface is derived based on the first-order radiative transfer technique. At first, the scattering mechanisms of the scattering model are analyzed for various conditions of the vegetation canopies. Then, the scattering model is simplified step by step for developing an appropriate inversion algorithm. For verifying the scattering model and the inversion algorithm, the polarimetric backscattering coefficients at 1.85 GHz, as well as the ground truth data, of a tall-grass field are measured for various soil moisture conditions. The genetic algorithm is employed in the inversion algorithm for retrieving soil moisture and surface roughness from the radar measurements. It is found that the scattering model agrees quite well with the measurements. It is also found that the retrieved soil moisture and surface roughness parameters agree well with the field-measured ground truth data.

• 한국지하수토양환경학회지:지하수토양환경
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• 제23권5호
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• pp.37-44
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• 2018

Soil trace elements and their bioaccumulation in agricultural products have attracted widespread concerns, yet the crop uptake characteristics of trace elements in different soil-plants systems have been rarely investigated. Experiments were carried out to investigate the effect of soil properties on trace element concentrations in cabbage and radish. Soil pH and total organic matter were major factors influencing trace elements transfer from soil to vegetables. Inclusion of other soil properties in the stepwise regression analysis improved the regression models for predicting trace element concentrations. Consideration of other soil properties should be taken into account for more precise prediction of trace element concentrations in the two vegetables, which could help quantitatively evaluate the ecologic risk of toxic trace elements accumulation in crops.

• Geomechanics and Engineering
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• 제17권5호
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• pp.439-444
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• 2019

It is generally known that high strength soil is indicative of well-graded particle size distribution. However, there are some special cases of firm ground despite poor grade distribution, especially a specific gap-graded soil. Based on these discoveries, this study investigated the development of an additive of gap-graded soils designed to increase soil strength. This theoretical concept was used to calculate the mixed ratio required for optimal soil strength of the ground sample. The gap-graded aggregate was added according to Plato's polyhedral theory and subsequently calculated ratio and soil strength characteristics were then compared to characteristics of the original soil sample through various test results. In addition, the underground stress transfer rate was measured according to the test conditions. The test results showed that the ground settlement and stress limit thickness were reduced with the incorporation of gap-graded soil. Further field tests would confirm the reproducibility and reliability of the technology by using gap-graded soil to reinforce soft ground of a new construction site. Gap-graded soil has the potential to reduce the construction cost and time of construction compared to other reinforcing methods.

• 한국지반공학회논문집
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• 제22권6호
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• pp.51-61
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• 2006

말뚝-지반의 상호거동과 다양한 설계변수들의 불확실성을 고려한 축하중을 받는 단말뚝의 위험도를 정량화하기 위하여 효율적이고 정확한 복합 신뢰성해석 기법이 본 논문에서 제안되었다. 제안된 신뢰성해석 기법은 응답면기법, 유한차분법, 일차신뢰도법과 반복 선형보간기법의 개념들을 지능적으로 결합하였다. 단말뚝-지반계의 확정적 해석을 위해서 하중전이법과 유한차분법을 통합하였다. 하중조건, 말뚝의 재료와 단면특성, 그리고 지반특성과 관련된 불확실성을 명확하게 고려하였다. 말뚝과 지반의 사용성 한계상태 및 강도 한계상태에 대한 위험도를 평가하였다. 축하중을 받는 사실적인 말뚝-지반계의 안전성평가에 대한 제안기법의 적용성, 정확성 및 효율성을 몬테카를로 시뮬레이션의 결과와 비교함으로써 검증하였다.

• 방사성폐기물학회지
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• 제11권1호
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• pp.63-68
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• 2013

논의 $^{99}Tc$ 오염 시 소석회와 유기질 비료의 토양 첨가가 쌀알 내 $^{99}Tc$ 농도 저감 대책으로서 유용한지 알아보기 위하여 온실 내에서 두 가지 논토양에 대해 포트실험을 수행하였다. 모내기 15 일 전에 약 20 cm 깊이에 해당하는 상부 토양을 상기 농용 물질과 $^{99}Tc$로 처리하였다. 처리 효과는 토양 중 농도에 대한 작물체 내 농도의 비로 정의되는 전이계수(TF)로 비교하였다. 대조 작물체의 경우 두 토양에서 현미 TF 값은 $4.1{\times}10^{-4}$ 및 $4.3{\times}10^{-4}$였다. 각종 유형의 첨가 중에서 한 토양에 대해 60%정도의 TF 값 감소를 나타낸 소석회 저수준 첨가(약 0.6 kg $m^{-2}$)만이 대책으로서 이용 가능성이 있을 것으로 판단되었다. 다른 한 토양에서는 동 첨가의 효과가 거의 없었으므로 다수의 토양에 대한 평균적인 효과를 알아내는 것이 중요하다. 두 가지 다른 수준의 유기질 비료의 첨가는 모두 TF 값을 증가시켰다. 위보다 더 낮은 수준의 소석회 첨가에 대해 실험을 수행할 필요가 있을 것으로 사료되었다.