• 제목/요약/키워드: normal soil

검색결과 675건 처리시간 0.025초

A KINETIC ANALYSIS OF ORGANIC RELEASE FROM THE AQUIFER SOIL IN RIVERBANK/BED FILTRATION

  • Ahn, Kyu-Hong;Moon, Hyung-Joon;Kim, Seung-Hyun
    • Environmental Engineering Research
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    • 제10권4호
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    • pp.199-204
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    • 2005
  • Experiments were performed to estimate the organic release from the aquifer soil in riverbank and/or riverbed filtration via a kinetic approach. Organic release was assumed as a reaction of first order regarding concentrations in both soil and water phases. The reaction rate constants were obtained by comparing the model predictions with the experimental data of organic release reaction and the equilibrium distribution of organic matter between water and soil phases. Results show that the organic release from the aquifer soil was not negligible under normal conditions in Korea reaching 4.7mg-COD/L-day. This indicates that manganese and iron start to be released from aquifer soil in the riverbank filtration in the middle reach of the Nakdong river if the travel time of the filtrate exceeds about 5 days. It was also seen that the COD of the soil organic matter was 0.89mg-COD/mg-OM and that 65% of the COD was BOD5.

답토양(畓土壤)의 인산완형액(燐酸緩衡液)에 의(依)한 지력질소(地力窒素) 평가(評價)에 관(關)한 연구(硏究) (Evaluation of Potentially Available Soil Nitrogen by Using Buffer Phosphote Solution of pH7)

  • 안상배
    • 한국토양비료학회지
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    • 제19권4호
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    • pp.327-332
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    • 1986
  • pH7 인산완형용액(燐酸緩衡容液)으로 추출(抽出)한 지력질소(地力窒素)를 몇개의 토양(土壤)에서 비교평가(比較評價)하기 위(爲)하여 퇴비(堆肥), 석회(石灰) 및 규회석(珪灰石)을 32년간(年間) 장기연용(長期連用)한 사질답(砂質畓), 이앙전(移秧前) 70일간(日間) 담수(湛水) 및 무담수(無湛水)한 사질답(砂質畓), 다수확(多收穫)을 낸 보통답(普通畓) 및 인접(隣接)한 농가(農家)의 보통답(普通畓)을 실내조건(室內條件)으로 지력질소평가(地力窒素評價), 지력질소소장(地力窒素消長), 지력질소(地力窒素)와 추출질소(抽出窒素)와의 관계(關係) 및 답유형별(畓類型別) 지력질소(地力窒素)에 의(依)한 질소시비량결정(窒素施肥量決定) 등(等)을 분석검토(分析檢討)하였던 바 다음과 같은 결과(結果)를 얻었다. 1. 동일비료(同一肥料)를 연용(連用)할 사질답(砂質畓)에서 처리별(處理別) 인산완형액(燐酸緩衡液)에서 추출(抽出)된 유기태질소(有機態窒素)는 3요소(要素)+퇴비구(堆肥區), 3요소구(要素區), 3요소(要素)+퇴비(堆肥)+석회(石灰)+규회석구(珪灰石區), 3요소(要素)+석회(石灰)+규회석구(珪灰石區), 3요소(要素)+규회석(珪灰石), 무비구(無肥區) 순위(順位)로 많았다. 2. 3요소(要素) 및 3요소(要素)+퇴비구(堆肥區) 처리(處理)에서 생육시기별(生育時期別)로 지력질소(地力窒素) 소장(消長)을 보면 처리(處理)에 관계(關係)없이 시험전(試驗前)에 비(比)해 유수형성기(幼穗形成期), 출수기(出穗期)로 생육(生育)이 경과(經過)됨에 따라 유기태질소함량(有機態窒素含量)은 감소(減少)되는 경향(傾向)이었다. 3. 다수확(多收穫)을 낸 보통답(普通畓)과 인근보통답(隣近普通畓)에서 비교(比較)할때 T-N, Org-N, $NH_4-N$ 성분(成分)은 다수확답(多收穫畓), $NO_3-N$는 인근답(隣近畓)에서 많았다. 특(特)히 4주간(週間) 담수항온후(湛水恒溫後) 생성(生成)된 $NH_4-N$와 추출(抽出)된 전질소(全窒素)N와는 1%의 유의성(有意性)이 있는 정(正)의 관계(關係)가 있었다. 4. 담수(湛水) 및 무담수(無湛水)한 사질답(砂質畓)에서 토양유기태질소(土壤有機態窒素)는 무담수처리구(無湛水處理區)에서 많았으나 도체내(稻體內) 질소흡수량(窒素吸收量)은 반대(反對)로 담수구(湛水區)에서 많았다. 5. 답유형별(畓類型別) 토양(土壤)의 추출전질소(抽出全窒素)는 보통답(普通畓), 사질답(砂質畓), 미숙답(未熟畓), 염해답(鹽害畓) 순(順)으로 많았으며 지력질소(地力窒素)에 의(依)한 추정질소시비량(推定窒素施肥量)은 반대(反對)로 염해답(鹽害畓), 미숙답(未熟畓), 사질답(砂質畓), 보통답(普通畓) 순위(順位)였다.

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A Large Slipping Finite Element Model for Geosynthetics Interface Modeling

  • Yi, Chang-Tok
    • 한국지반공학회지:지반
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    • 제12권3호
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    • pp.35-48
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    • 1996
  • 보강토구조물은 흙과 보강재 사이에 큰 변형이 발생하며 보강토구조물의 파괴양상도 보강재의 미끄러짐이나 변형에 의해 지배되며, 때때로 보강재의 재료의 파괴보다는 미끄러짐에 의해 보강토구조물이 파괴되므로 큰변형이 발생하는 흙-보강재의 모델링이 필요하다. 고형 및 액체폐기물 매립장에 쓰이는 라인너 시스템은 매립장의 경사와 쓰레기하중에 의해 큰 변형이 발생하게 된다. 이러한 큰 변형의 문제는 기존의 접촉요소로써 모델링하는데 많은 제약 이 따른다. 본 논문에서는 이러한 흙과 토목섬유보강사이의 큰 만행을 모델링할 수 있는 접촉은소를 제안하였으며, 그 이론과 그 모델의 적용성에 대하여 논하였다.

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습지 수제부에서 삽목방법에 따른 갯버들 생장율 및 토양 유실 억제 효과 (The Growth Rate of Salix Gracilistyla Miq. and its Effect of Protecting Soil from Dispersion Depending on the Planting Method Applied to Shore-marginal Slope)

  • 이춘석;류남형
    • 한국환경복원기술학회지
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    • 제6권3호
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    • pp.56-68
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    • 2003
  • The main purpose of this study was to verify the shore margin protection effect of the root system of Salix gracilistyla Miq. developed from direct sticking cuttings on wetland, through the measurement of root growth and comparison of soil slaking rate depending on the planting method applied to shore-marginal slope. Comparison of growth rate and soil dispersion rate was made between five planted slope and one naked slope. The planting methods applied to the planted slope were (a) horizontally layed burying of stick(45cm) bundle (b) horizontally layed covering the slope with sticks (c) horizontally fencing with normal cuttings(20cm) (d) elected sticking of normal cutting at equal distances (e) random scattering short cuttings(3-4cm). As results, the most effective planting method was horizontally layed burying, and in order to increase its efficiency scattering the live stem chips in 2-3cm on the slope is recommended. The growth of root was negatively regressive to the distance from water floor.

Dynamic elastic local buckling of piles under impact loads

  • Yang, J.;Ye, J.Q.
    • Structural Engineering and Mechanics
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    • 제13권5호
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    • pp.543-556
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    • 2002
  • A dynamic elastic local buckling analysis is presented for a pile subjected to an axial impact load. The pile is assumed to be geometrically perfect. The interactions between the pile and the surrounding soil are taken into account. The interactions include the normal pressure and skin friction on the surface of the pile due to the resistance of the soil. The analysis also includes the influence of the propagation of stress waves through the length of the pile to the distance at which buckling is initiated and the mass of the pile. A perturbation technique is used to determine the critical buckling length and the associated critical time. As a special case, the explicit expression for the buckling length of a pile is obtained without considering soil resistance and compared with the one obtained for a column by means of an alternative method. Numerical results obtained show good agreement with the experimental results. The effects of the normal pressure and the skin friction due to the surrounding soil, self-weight, stiffness and geometric dimension of the cross section on the critical buckling length are discussed. The sudden change of buckling modes is further considered to show the 'snap-through' phenomenon occurring as a result of stress wave propagation.

유적지에서 출토된 고대 토양의 과학적 분석연구-해남 분토리 및 경주 금장리 유적지 토양을 중심으로 (The Scientific Analysis of the Archaeological Soil excavated at bunto-ri, Haenam and kumjang-ri, Kyungju)

  • 서민석;김민희
    • 보존과학연구
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    • 통권27호
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    • pp.203-214
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    • 2006
  • The work focuses on the chemical analysis of organic residues in archaeological soils. Particularly, the detection of manuring in archaeological soils can provide important information concerning early human behavior, diet, parasites, ecological adeptation. In this study, archaeological soils excavated at bunto-ri, Haenam and kumjang-ri, Kyungju were used to assess the possibility as indicators of ancient human activity in archaeological areas. The sampled soils were analyzed soil color, pH for their physical and chemical properties and GC/MSD to detect and quantify specific compound. The results showed that the sampled soils were normal pH(6.8~7.2) and soil color of light brown to yellowish brown. Also, the result from the GC/MS analysis indicated that their compounds were hexadecanoic acid, octadecanoic acid, nonadecane, docosanoic acid, methyl ester, teracosanoic acidand methyl este from bunto-ri site and 1-heptadecene, cyclotetracosane, tetracosane, cyclotetracosane,1-docosene, n-nonadecane, tetracosanoic acid methyl ester, cyclooctacosane, 1-nonadecene, eicosane, cyclotriacontane from kumjang-ri site. These compounds are not only normal soil materials but also animal lipid compounds. And the more scientific analysis of the soils will solve a curiosity for artificially incoming.

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Effect of cement dust on soil physico-chemical properties around cement plants in Jaintia Hills, Meghalaya

  • Lamare, R. Eugene;Singh, O.P.
    • Environmental Engineering Research
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    • 제25권3호
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    • pp.409-417
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    • 2020
  • Investigation was carried out to assess the effect of cement dust deposition on the physico-chemical properties of soil near some cement plants in Jaintia Hills, Meghalaya. Soil samples were collected and analysed and compared with the control site. Comparison of various soil physico-chemical parameters revealed that cement dust emanating from cement plants has changed the soil quality in the surrounding areas of cement plants. The normal soil pH in the area is generally acidic. However, due to the continuous deposition of cement dust soil pH was found slightly alkaline near the cement plants. The higher values of soil parameters such as electrical conductivity and bulk density were also noticed near the cement plants. However, lower values of water holding capacity, soil moisture content, soil organic carbon and total nitrogen content were found compared to the control sites. The effect of cement dust deposition on soil is more in areas nearer to the cement plants. At present the changes may not be so serious but if this trend continues, soil properties of a vast area around the cement plants are likely to change leading to multiple effects on flora, fauna and socio-economy of the area.

얕은기호 침하의 확률론적 해석 (Probabilistic Analysis of Shallow Foundation Settlements)

  • 정두영;오병현
    • 한국지반공학회지:지반
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    • 제9권3호
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    • pp.77-90
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    • 1993
  • 얕은기초의 침하해석에 관련된 토질정수, 하중 및 지층구조는 많은 불확실성을 내포하고 있어 확률적 특성을 고려한 해석이 필요하다. 본 연구는 Monte Carlo Method를 이용하여 독립후팅들로 구성된 얕은기초의 침하에 관한 확률론적 해석을 하였다. 변수의 불확실성을 고려하기 위하여 토질정수와 하중은 정규분포의 확률변수로 가정하여 독립후팅의 침하평균 및 변동계수를 구하고 각 독립후팅의 침하도 정규분포하는 것으로 가정하였다. 또한 지반내에 존재할 수 있는 연약토질 포켓 (soft soil pocket)의 확률을 고려한 각 독립후팅의 침하는 Markov process를 따르는 것으로 하였다. 이와같은 각 변수들의 변화에 따라 최대침하와 부등칭하의 허용한계 초과확률에 대한 민감도분석을 하였으며, 얕은기초의 침하해석은 각 변수의 불확실성과 지반조건을 고려하는 것이 타당하다고 판단된다.

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454 Pyrosequencing Analysis of Bacterial Diversity Revealed by a Comparative Study of Soils from Mining Subsidence and Reclamation Areas

  • Li, Yuanyuan;Chen, Longqian;Wen, Hongyu;Zhou, Tianjian;Zhang, Ting;Gao, Xiali
    • Journal of Microbiology and Biotechnology
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    • 제24권3호
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    • pp.313-323
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    • 2014
  • Significant alteration in the microbial community can occur across reclamation areas suffering subsidence from mining. A reclamation site undergoing fertilization practices and an adjacent coal-excavated subsidence site (sites A and B, respectively) were examined to characterize the bacterial diversity using 454 high-throughput 16S rDNA sequencing. The dominant taxonomic groups in both the sites were Proteobacteria, Acidobacteria, Bacteroidetes, Betaproteobacteria, Actinobacteria, Gammaproteobacteria, Alphaproteobacteria, Deltaproteobacteria, Chloroflexi, and Firmicutes. However, the bacterial communities' abundance, diversity, and composition differed significantly between the sites. Site A presented higher bacterial diversity and more complex community structures than site B. The majority of sequences related to Proteobacteria, Gemmatimonadetes, Chloroflexi, Nitrospirae, Firmicutes, Betaproteobacteria, Deltaproteobacteria, and Anaerolineae were from site A; whereas those related to Actinobacteria, Planctomycetes, Bacteroidetes, Verrucomicrobia, Gammaproteobacteria, Nitriliruptoria, Alphaproteobacteria, and Phycisphaerae originated from site B. The distribution of some bacterial groups and subgroups in the two sites correlated with soil properties and vegetation due to reclamation practice. Site A exhibited enriched bacterial community, soil organic matter (SOM), and total nitrogen (TN), suggesting the presence of relatively diverse microorganisms. SOM and TN were important factors shaping the underlying microbial communities. Furthermore, the specific plant functional group (legumes) was also an important factor influencing soil microbial community composition. Thus, the effectiveness of 454 pyrosequencing in analyzing soil bacterial diversity was validated and an association between land ecological system restoration, mostly mediated by microbial communities, and an improvement in soil properties in coal-mining reclamation areas was suggested.

The use of the semi-empirical method to establish a damping model for tire-soil system

  • Cuong, Do Minh;Ngoc, Nguyen Thi;Ran, Ma;Sihong, Zhu
    • Coupled systems mechanics
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    • 제7권4호
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    • pp.395-406
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    • 2018
  • This paper proposes a linear damping model of tire-soil system using semi-empirical method. A test rig was designed and developed to measure the vertical equivalent linear damping ratio of tire only and tire-soil system using Free-Vibration Logarithmic Decay Method. The test was performed with two kinds of tractor tires using a combination of five inflation pressure levels, two soil depths and four soil moisture contents in the paddy soil. The results revealed that the linear damping ratio of tires increased with decreasing tire inflation pressure; the linear damping ratio of tire-soil system also increased with decreasing tire inflation pressure and increased with the increasing soil depth (observed at 80 and 120 mm). It also increased with a relative increase of soil moisture contents (observed at 37.9%, 48.8%, 66.7% and 77.4%). The results also indicated that the damping ratio of tire-soil system was higher than that of tire only. A linear damping model of tire-soil system is proposed as a damping model in parallel which is established based on experimental results and vibration theory. This model will have a great significance in study of tractor vibration.