• 한국수자원학회논문집
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• 제31권6호
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• pp.795-806
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• 1998

토양수분은 기후, 토양 및 지표면의 조건 등에 의해 영향을 받는다. 특히, 급격한 도시화 및 산업화의 영향으로 다른 영향인 자들 보다 지표면 조건의 변화가 크게 바뀌고 있다고 할 수 있으며 본 연구에서는 이러한 지표면 조건의 변화가 토양수분에 어떻게 영향을 미칠 수 있는지를 간단한 토양수분 동역학 모형을 이용하여 평가해 보았다. 먼저, 본 논문에서는 토양수분의 시간적 공간적 통계특성을 정량화 해보기 위해 논문의 전반부를 Washita ’92 자료 및 Monsoon ’90 자료의 1차원 및 2차원의 통계적 특성을 정리하는데 할해하였으며, 논문의 후반부에서 지표면 조건의 변화를 모형 매개변수의 통계적인 특성을 변화시킴으로서 고려하고 각각의 경우 토양수분이 어떻게 반응하는가를 살펴보았다. 사용된 모형은 선형저수지의 개념에 토양상층에서의 공간적 거동을 고려하기 위하여 확산의 개념을 도입하여 구성된 모형이다. 모형의 주요 매개변수는 손실률과 확산계수로 나타나고, 이들은 관측자료의 통계특성을 이용하여 추정될 수 있다. 지표면 조건의 변화는 모형의 매개변수에 다양한 통계특성을 적용하고 고려하게 된다. 특히, 본 연구에서는 지표면 조건의 평균적인 변화보다 이의 공간적인 분산도의 변화에 초점을 맞추어 분석하였다. 이는 평균적인 지표면 조건의 변화는 선형저수지의 이론에 근거하여 그 영향을 쉽게 판단할 수 있기 때문이다. 본 연구의 결과를 정리하면 다음과 같다. (1) 지표면 상태의 분산도가 커질 경우 토양수분은 더 쉽게 손실된다, (2) 토양수분의 분산도는 모의 초기에 강우의 영향으로 크게 나타나나 시간이 경과함에 따라 감소하고 점차 지표면 상태의 분산특성를 나타내게 된다, (3) 지표면 유출이나 토양상층에서의 토양수분 이동에 따른 확산의 영향은 지표면 유출이 존재하는 강우기간으로 제한되며 전체적으로 토양수분의 변화에 미미한 영향을 미친다.

• 동굴
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• 제42권2호
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• pp.41-63
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• 1995

An abundance of information is available regarding soil horizons and their characteristics. Several methods can be used to gather and analyze this information. Through the use of qualitative analysis in the field, and laboratory and statistical analysis, a soil can be compared and analyzed with a great deal of scrutiny. Four soil pits were excavated in Citrus County Florida and samples were collected from each master horizon. Through the use of qualitative and quantitative analysis these samples were compared and analyzed in order to identify unique, as well as homogeneous features. It was determined that the soil profile designated Old Pit was different than other profiles because of landscape position and variations in parent material. Landscape position (ie. slope position) also influenced the genesis and evolution of the soils in the other three profiles(Profile 1, 2 and 3).

• Geomechanics and Engineering
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• 제37권1호
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• pp.9-19
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• 2024

This study presents an energy analysis for large-strain cavity expansion problem based on the general strength criterion and energy theory. This study focuses on the energy dissipation problem during the cavity expansion process, dividing the soil mass around the cavity into an elastic region and a plastic region. Assuming compliance with the small deformation theory in the elastic region and the large deformation theory in the plastic region, combined with the general strength criterion of soil mass and energy theory, the energy dissipation solution for cavity expansion problem is derived. Firstly, from an energy perspective, the process of cavity expansion in soil mass is described as an energy conversion process. The energy dissipation mechanism is introduced into the traditional analysis of cavity expansion, and a general analytical solution for cavity expansion related to energy is derived. Subsequently, based on this general analytical solution of cavity expansion, the influence of different strength criterion, large-strain, expansion radius, cavity shape and characteristics of soil mass on the stress distribution, displacement field and energy evolution around the cavity is studied. Finally, the effectiveness and reliability of theoretical solution is verified by comparing the results of typical pressure-expansion curves with existing literature algorithms. The results indicate that different strength criterion have a relatively small impact on the displacement and strain field around the cavity, but a significant impact on the stress distribution and energy evolution around the cavity.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.361-364
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• 2005

The use of remotely sensed data and geographic information system (GIS) to develop conservation-oriented watershed management strategies on Imha Dam, Korea, is presented. The change of land use for study area was analyzed using multi-temporal Landsat imagery. A soil loss model was executed within a GIS environment to evaluate watershed management strategies in terms of soil loss. In general, remotely sensed data provide efficient means of generating the input data required for the soil loss model. Also, GIS allowed for easy assessment of the relative erosion hazard over the watershed under the different land use change options. The soil loss model predicted substantial declines in soil loss under conservation-oriented land management compared to current land management for Imha Dam. The results of this study indicate that soil loss potential (5,782,829 ton/yr) on Imha Dam in 2003 is approximately 1.27 times higher than that (4,557,151 ton/yr) in 1989. This study represents the first attempt in the application of GIS technology to watershed conservation planning for Imha Dam. The procedures developed will contribute to the evolution of a decision support system to guide the land planning and dam management in Imha Dam.

• 한국물환경학회지
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• 제25권4호
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• pp.507-514
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• 2009

In this study, a dynamic modeling scheme is presented to describe the probabilistic structure of soil water and plant water stress index under stochastic precipitation conditions. The proposed model has the form of the Fokker-Planck equation, and its applicability as a model for the probabilistic evolution of the soil water and plant water stress index is investigated under a climate change scenario. The simulation results of soil water confirm that the proposed soil water model can properly reproduce the observations and show that the soil water behaves with consistent cycle based on the precipitation pattern. The simulation results of plant water stress index show two different PDF patterns according to the precipitation. The simple impact assessment of climate change to soil water and plant water stress is discussed with Korean Meteorological Administration regional climate model.

• 한국환경농학회지
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• 제16권4호
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• pp.320-326
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• 1997

제초제 imazapyr의 토양환경중 행동을 구명하기 위하여 물리화학적 특성이 상이한 8종의 토양을 이용하여 $^{14}CO_2$로의 무기화 및 흡착 시험을 수행하여 얻은 결과를 요약하면 다음과 같다. 1. 물리화학적 특성이 상이한 8종의 토양중 배양기간 동안 발생된 $^{14}CO_2$의 양은 총 처리 방사능의 약 1.5${\sim}$4.9%로써 토양에 따라 상이한 방출율을 보였다. pH가 낮고 유기물이 많은 토양 C, G 및 H에서는 낮은 $^{14}CO_2$ 방출량을 보인 반면 pH가 높고 유기물이 적은 토양 B와 D에서는 높은 $^{14}CO_2$ 방출율을 보였다. 2. Imazapyr의 흡착실험에서 평형농도 도달시간은 네 토양 모두에서 약 3시간 이었다. 물리화학적 성질이 상이한 토양에서 0.25${\sim}$28.32%의 흡착율을 보였으며, 토양구성 요소중에서, 유기물 함량이 토양에 의한 imazapyr의 흡착에 가장 큰 영향을 미쳤다. Freundlich 흡착상수$(K_f)$는 유기물의 함량이 2.0${\sim}$21.3배 증가함에 따라 5.5${\sim}$25.6배 증가하였다. 그러므로 토양 유기물이 imazapyr의 흡착에 미치는 범위는 점토가 미치는 것보다 더 큼이 분명하다. $K_f$값은 토양 C, D, G 및 H에서 각각 0.44, 0.08, 0.65 및 2.05이었으며, 모든 토양에서 $K_d$와 유사한 값을 보였다.

• 한국환경농학회지
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• 제7권1호
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• pp.34-42
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• 1988

제지(製紙)슬러지의 시용량(施用量)을 300, 600, 900 및 1,200kg/10a으로 달리하고 각(各) 시용수준별(施用水準別) C/N율(率)을 30 : 1로 조절(調節)하여 Pot시험(試驗)을 실시(實施)함으로써 토양중(土壤中) 휘발성저급지방산조성(揮發性低級脂肪酸組成)을 시기별(時期別)로 조사(調査)하였다. 그리고 제지(製紙)슬러지의 분해양상(分解樣相) 및 토양중(土壤中) $CO_2$발생량(發生量)을 경시적(經時的)으로 조사(調査)하였으며, 토양중(土壤中) 휘발성지방산함량(揮發性脂肪酸含量)과 수도(水稻)의 무기성분흡수(無機成分吸收)와의 관계(關係)등을 검토(檢討)한 결과(結果)는 다음과 같다. 1. 제지(製紙)슬러지 시용후(施用後) 120일간(日間)의 분해율(分解率)은 $35{\sim}44%$, C/N율(率)은 $55{\sim}82$였다. 2. 토양중(土壤中) $CO_2$발생량(發生量)은 슬러지의 시용량(施用量)이 많을수록 증가(增加)하였으며 $CO_2$발생량(發生量)과 슬러지의 분해율(分解率) 및 토양중(土壤中) 휘발성방린산함량(揮發性肪燐酸含量)과 고도(高度)의 유의적(有意的)인 정(正)의 상관(相關)이 있었다. 3. 토양중(土壤中) 휘발성지방산(揮發性脂肪酸) acetic, propionic, i-butyric, butyric, i-valeric 및 valeric acid의 6종(種)이 동정(同定)되었으며, 그 함량(含量)은 슬러지의 시용량(施用量)이 많을수록 증가(增加)하였고, 슬러지시용후(施用後) 25일경(日頃)이 가장 높았으며 그후 시일(時日)이 경과할수록 감소(減少)하는 경향(傾向)이었다. 4. 토양중(土壤中) 휘발성지방산(揮發性脂肪酸)은 수도(水稻)의 초기생육(初期生育)을 억제(抑制)하였으며 벼이앙후(移秧後) 25일(日)의 토양중(土壤中) acetic, propionic, i-valeric acid 함량(含量)과 수도(水稻)의 질소(窒素), 린산(燐酸), 칼리, 석탄고토(石炭苦土) 및 규산흡수량간(珪酸吸收量間)에는 유의적(有意的)인 역상관(逆相關)이 있었고, butyric acid 함량(含量)과 린산(燐酸) 및 석탄흡수량간(石炭吸收量間)에도 같은 경향(傾向)이었다. 5. 이앙후(移秧後) 25일(日)의 토양중(土壤中) 총휘발성지방산함량(總揮發性脂肪酸含量)은 토양중(土壤中) $Fe^{++}$ 및 $Mn^{++}$ 함량(含量)과 유의적(有意的)인 정의(正) 상관(相關)이 있었으며 $Fe^{++}$ 함량(含量)은 특히 acetic acid 함량(含量)과 고도(高度)의 유의적(有意的)인 정(正)의 상관(相關)이 있었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권7호
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• pp.90-102
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• 2015

To understand the hyrogeochemical variation of bedrock aquifer during underground space construction, various graphical methods including multiple-component plots and chemical trends were used to estimate the mixing rate between seawater and freshwater and to investigate the evolution of water quality. The water chemistry and mixing rate between fresh and sea waters, which are generally localized in the construction area (MW-7, in land), shows typical characteristics of freshwater that doesn’t affect its validity as seawater intrusion. Especially, the water chemistry of a MW-4 (coastline) was classified as Na-Cl type, Na-HCO₃ type, and Ca-Cl type due to the influence of the seawater intrusion. And hydrogeochemical and isotopic data show that local freshwater is subjected to geochemical processes, such as reverse ion-exchange. Throughout the Chadha’s diagrams, four different case histories with the temporal and spatial variation of groundwaters in the study area were proposed, which is recommended to interpret the hydrogeochemical reactions effectively.

• Geomechanics and Engineering
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• 제35권6호
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• pp.627-636
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• 2023

The essence of subgrade mud pumping under train load is the migration of fine particles in subgrade soil. The migration of fine particles will change the pore structure of overlying ballast, thus affecting the mechanical properties and hydraulic properties of ballast layer. It is of great theoretical significance and engineering value to study the effect of fine particle migration on the pore structure of ballast layer under cyclic loading. In this paper, a tailor-made subgrade mud pumping test model and an X-ray computed tomography (CT) scanning equipment were used to study the influence of migration of fine particles in subgrade soil on the pore parameters (plane porosity, volume porosity, pore distribution and pore connectivity) of overlying ballast under cyclic loading. The results show that the compression of ballast pores and the blockage of migrated fine particles make the porosity of ballast layer decreases gradually. And the percentage of small pores in ballast layer increases, while the percentage of large pores decreases; the connectivity of pores also gradually decreases. Based on the test results, an empirical model of ballast porosity evolution under cyclic loading is established and verified.

• 한국환경보건학회지
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• 제32권6호
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• pp.578-584
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• 2006

This research was conducted to estimate the effect of C/N ratio control on composting of TNT (2,4,6 trinitrotoluene)-contaminated soil. Glucose or acetone was selected to control C/N ratio of the contaminated soil. The C/N ratios of the controlled experiment and no controlled one were 26.0 and 6.6, respectively. During 45days, the degradation efficiency (96.0 or 91.8%) of acetone or glucose C/N ratio controlled soil was higher than that (78.4%) of no C/N ratio controlled case. The first order degradation rate constant of glucose or acetone C/N ratio control was 0.0641 or 0.0820/day. This constant was over twice 0.0356/day of no C/N ratio control. The C/N ratio control with glucose or acetone also showed a rather high $CO_2$ evolution than that without C/N ratio control. It was proven that C/N ratio control for composting of TNT-contaminated soil improved the treatment efficiency.