• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.129-134
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• 2000

Hardening agent has been the traditional material for surface soil stabilization a sat ground This study aims at determining optimal mixture ratio of hardening agent in accordance with the required design specificutions. Hardening agent is properly mixed with Fly ash, Gyosum, Slag and Cement for the etmmngite hydrates which is dective for early stabilization of unconsoliokrred soil. \ulcornerhe treated soil is the clay tint is widely found here and there in Koresz In this study, preliminary tests were performed to get optirml mixture ratio of stabilizer ingredient, and mrvine clay in Jin-Hae was used to get physid and Md properties. Labomtory tests of 50 stabilized soil were performed to get optimal mixture mtio for 16-stabilizer merial a 6 types, a d stabilizer mixing was determined

• Steel and Composite Structures
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• 제13권2호
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• pp.109-122
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• 2012

An efficient and accurate algorithm is proposed to evaluate the reliability of cable-stayed bridges accounting for soil-pile interaction. The proposed algorithm integrates the finite-element method and the response surface method. The finite-element method is used to model the cable-stayed bridge including soil-pile interaction. The reliability index is evaluated based on the response surface method. Uncertainties in the superstructure, the substructure and load parameters are incorporated in the proposed algorithm. A long span steel cable-stayed bridge with a main span length of 1088 m built in China is considered as an illustrative example. The reliability of the bridge is evaluated for the strength and serviceability performance functions. Results of the study show that when strength limit states for both girder and tower are considered, soil-pile interaction has significant effects on the reliability of steel cable-stayed bridges. Further, a detailed sensitivity study shows that the modulus of subgrade reaction is the most important soil-pile interaction-related parameter influencing the reliability of steel cable-stayed bridges.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.209-212
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• 2002

Main radionuclides of the soil waste stored in Korea Atomic Energy Research Institute are Co-60 and Cs-137. Moisture content of soil is 12%, pH of soil is 5.8, and content of organic matter is 2.2 %. Radioactive concentrations of the soil particle size of which is less than 0.063mm and soil in the drum surface of which is more than radiation dose rate 0.05mR/hr are higher. Meanwhile, radioactive concentration of soil in the drum surface of which is less than radiation dose rate 0.02 mR/hr are mostly lower. On using the mixing solution of ammonium sulfate and citric acid, 62% Co was removed from soil and 41% Cs was removed. Also, on using the mixing solution of ammonium nitrate and citric acid, 61% Co was removed from soil and 39% Cs was removed, and on using the mixing solution of ammonium potassium oxalate, 36% Co was removed and only 3% Cs was removed. And on using only water, removal efficiency is less than 5%.

• Earthquakes and Structures
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• 제19권1호
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• pp.1-16
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• 2020

This study presents an investigation of the dynamic interactions between a surface structure lying on two different soil deposits and a square-shaped buried structure embedded in the soil. To this end, a large number of numerical models are generated by using a well-known Finite Element Method software, i.e., OpenSEES. The interaction phenomenon is assumed to be affected by six different parameters. In the parametric study, these parameters are assumed to have various values in accordance with the engineering practices. A total of 1620 possible combinations of the parameter values are addressed in this study. 30 different numerical models are also generated as the 'free-field cases' to set a reference. The surface structure drift and acceleration amplifications are used as a measure to evaluate the dynamic interactions. The response (i.e., drifts and accelerations) amplifications are calculated as the ratio of the maximum surface structure response in any 'case' to the maximum surface structure response in corresponding free-field case. Variation of the response amplifications with any of the investigated parameters is addressed in this paper. The results obtained from the numerical analyses clearly reveal that the presence of a buried structure in the vicinity of a surface structure can cause both amplification and de-amplification of the surface structure responses, depending on the case parameters.

• 조명전기설비학회논문지
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• 제21권1호
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• pp.142-147
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• 2007

본 논문은 대지구조와 접지봉의 매설깊이에 따른 대지표면의 전위상승에 대해서 기술하였다. 대지표면의 전위상승에 따른 인체의 감전사고의 저감에 관한 기초적 자료를 제안하기 위해서 접지봉 부근에서의 대지표면전위를 계산하고 측정하였다. 접지봉 부근의 대지표면전위상승은 대지구조에 크게 의존하며, 매설깊이가 깊어질수록 낮아졌다. 대지표면전위상승은 접지봉의 직상부에서 최대이었으며, 측정결과는 접지해석프로그램으로 계산한 결과와 잘 일치하였다.

• 한국토양비료학회지
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• 제46권6호
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• pp.510-518
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• 2013

Corn was mainly cultivated in slope land during summer season when heavy rain falls so that soil loss occurs severely. Especially, soil disturbance and exposure of topsoil by conventional tillage intensifies soil loss by heavy rain. The aim of this study was to develop surface covering and tillage methods for reducing soil loss in corn cultivation. The experiment was conducted in 17% sloped lysimeter with 8 treatments including strip tillage after surface covering with rye residue, strip tillage after residue covering of several crops and sod culture, black polyethylene film covering after conventional tillage and control. Amount of runoff water and eroded soil, and corn growth were investigated. Amounts of runoff water in all plots except black polyethylene plot ranged from 152 to 375 $m^3\;ha^{-1}$, accounting for 13~32% of 1,158 $m^3\;ha^{-1}$ in control. Amount of eroded soil decreased by 94 to 99% (3 to 89 kg $ha^{-1}$) in plots of strip tillage after covering with crop residues compared to control with 1,739 kg $ha^{-1}$. Corn yields in plots of strip tillage after covering with crop residues ranged from 6.0 to 6.9 Mg $ha^{-1}$, while that of control was 6.5 Mg $ha^{-1}$. The results suggest that strip tillage methods after surface covering with crop residues are very effective on soil conservation of slope land in corn cultivation.

• 미생물학회지
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• 제35권1호
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• pp.78-81
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• 1999

1997년 10월 21일에 발생한 지리산 국립공원의 산불 지역을 대상으로 토양 미생물의 분포 밀도 변화에 대해 연구하였다. 산불 발생 직후 표층, 지하 5cm, 10cm, 20cm, 30cm의 각 깊이에서 토양 미생물의 밀도를 조사하였다. 표층과 지하 5cm 깊이에 분포하는 세균의 밀도는 산불이 없었던 인근 지역의 $10^6$CFU/g soil 수준에 비해 $10^2$ CFU/g soil 수준으로 감소하였다. 방선균은 표층에서 완전히 소멸되었으며 지하 5cm 깊이에서는 대조구의 $10^6$CFU/g soil 수준에 비해 낮은 $10^3$ CFU/g soil 수준이었다. 곰팡이는 표층과 지하 5cm 깊이 모두에서 완전히 소멸된 것으로 나타났다. 그러나 지하 10cm 이상의 깊이에 분포하는 미생물들의 밀도는 전혀 감소되지 않았다. 또한 산불 발생 후 토양 미생물의 분포 회복 양상을 알아보기 위해 표층과 지하 5cm 깊이에서 경시적으로 밀도를 조사하였다. 산불 발생 2개월만에 미생물 밀도의 대부분은 크게 증가하여 산불이 없었던 인근 지역과 비슷하였으나토양 표층에 분포하는 방선균만은 산불 발생 4개월 후에도 여전히 대조구의 $10^6$ CFU/g soil 수준에 비해 낮은 $10^4$CFU/g soil 수준을 나타내었다.

• 한국농공학회논문집
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• 제48권5호
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• pp.51-60
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• 2006

In order to examine the heat transfer characteristic of a soil warming system and effects of soil warming on the greenhouse heating load, control experiments were performed in two greenhouses covered with double polyethylene film. One treated the soil warming with an electric heat wire and the other treated a control. Inside and outside air temperature, soil temperature and heat flux, and heating energy consumption were measured under the set point of heating temperature of $5,\;10,\;15,\;and\;20^{\circ}C$, respectively. Soil temperatures in a soil warming treatment were observed $4.1\;to\;4.9^{\circ}C$ higher than a control. Heating energy consumptions decreased by 14.6 to 30.8% in a soil warming treatment. As the set point of heating temperature became lower, the rate of decrease in the heating energy consumptions increased. The percentage of soil heat flux in total heating load was -49.4 to 24.4% and as the set point of heating temperature became higher, the percentage increased. When the set point of heating temperature was low in a soil warming treatment, the soil heat flux load was minus value and it had an effect on reducing the heating load. Soil heat flux loads showed in proportion to the air temperature difference between the inside and outside of greenhouse but they showed big difference according to the soil warming treatment. So new model for estimation of the soil heat flux load should be introduced. Convective heat transfer coefficients were in proportion to the 1/3 power of temperature difference between the soil surface and the inside air. They were $3.41\;to\;12.42\;W/m^{2}^{\circ}C$ in their temperature difference of $0\;to\;10^{\circ}C$. Radiative heat loss from soil surface in greenhouse was about 66 to 130% of total heating load. To cut the radiation loss by the use of thermal curtains must be able to contribute for the energy saving in greenhouse.

• 한국지반신소재학회논문집
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• 제4권3호
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• pp.45-52
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• 2005

대부분의 항만구조물은 초연약 지반상에 축조되고 있으며 도로나 건물부지에는 지반개량이 필요하다. 이 논문에서는 여러 사례연구를 통하여 표층처리후의 복토사례에 대하여 몇가지 고려사항을 언급하였다. 또한, 모래나 산토를 이용한 복토공법에 대하여 강도적용이 고려되었다. 국내 복토공법 토목섬유 인장강도는 15t/m, 복토두께는 1.6~3.1m, 점토지반의 표층강도는 $0.2{\sim}1.2t/m^2$이 대표적이다. 표층처리공 시공시 발생되는 지반교란, 점토유출, 장비전도 등의 사고를 최소화하기 위한 연구가 필요하다.

• 대한토목학회논문집
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• 제26권1D호
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• pp.141-147
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• 2006

강우에 의해서 발생하는 토양유실은 비옥한 표토를 유실시켜 생산성의 저하를 초래하고, 유실된 토양입자는 하천이나 호수, 댐 등에 퇴적되어 저수용량의 감소와 수질관리에 어려움을 야기 시키므로 이에 대한 대처가 필요하다. 본 연구에서는 위성 영상과 GIS 기법을 활용하여 유역내 토양침식에 영향을 미치는 토양조건, 피복조건, 지형조건들을 추출하고 이 요소들을 범용토양유실공식(USLE; Universal Soil Loss Equation)에 적용하여 유입퇴적량 및 유입 가능성이 높은 위치를 파악하였다. 또한 유입되어 하상에 쌓여 있는 퇴적량은 투과성이 강한 음향측심기를 활용하여 퇴적층과 지층의 고도 정보를 획득하여 산정하고 유실량과 퇴적량을 비교하여 퇴적되는 비율을 도출하였다.