• Title, Summary, Keyword: complicated soil profile

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Analysis of Soil-Structure Interaction Considering Complicated Soil Profile (복잡한 지층 형상을 고려한 지반-구조물 상호작용 해석)

  • Park, Jang-Ho
    • Journal of the Korean Society of Safety
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    • v.21 no.3
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    • pp.87-93
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    • 2006
  • When a structure is constructed at the site composed of soil, the behavior of a structure is much affected by the characteristics of soil. Therefore, the effect of soil-structure interaction is an important consideration in the design of a structure at the site composed of soil. Precise analysis of soil-structure interaction requires a proper description of soil profile. However, most of approaches are nearly unpractical for soil exhibiting material discontinuity and complex geometry since those cannot consider precisely complicated soil profiles. To overcome these difficulties, an improved integration method is adopted and enables to integrate easily over an element with material discontinuity. As a result the mesh can be generated rapidly and highly structured, leading to regular and precise stiffness matrix. The influence of soil profile on the response is examined by the presented method. It is seen that the presented method can be easily used on soil-structure interaction problems with complicated soil profile and produce reliable results regardless of material discontinuities.

Dynamic Analysis of Soil-Structure System Considering Characteristics of Structure and Complicated Soil Profile (구조물과 복잡한 지층 특성을 고려한 지반-구조물 시스템의 동적 해석)

  • Park, Jang-Ho
    • Journal of the Korean Society of Safety
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    • v.22 no.5
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    • pp.50-56
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    • 2007
  • In the past, a number of approaches, such as analytical, numerical or experimental methods, have been developed to deal with the soil-structure interaction effects. However, for many problems with complex geometry and material discontinuity most of approaches are nearly unpractical since it is difficult to model structures and complicated soil profiles precisely. This paper presents a soil-structure interaction analysis approach, which carl consider precisely characteristics of structures and complicated soil profiles. The presented approach overcomes the difficulties by adopting an unaligned mesh generation approach. From numerical examples, the applicability of the proposed approach is validated and dynamic responses of soil-structure systems subjected to earthquake loading are investigated considering characteristics of structures and complicated soil profiles.

Nonlinear Soil-Structure Interaction Analysis Considering Complicated Soil Profile (복잡한 지반 형상을 고려한 비선형 지반-구조물상호작용 해석)

  • Park, Jang-Ho
    • Journal of the Korean Society of Safety
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    • v.26 no.1
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    • pp.36-42
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    • 2011
  • This paper presents a nonlinear soil-structure interaction analysis approach, which can consider precisely characteristics of structures, complicated soil profiles and nonlinear characteristics of soil. Although many methods have been developed to deal with the soil-structure interaction effects in past years, most of them are nearly unpractical since it is difficult to model complicated characteristics of structure and soil precisely. The presented approach overcomes the difficulties by adopting an maligned mesh generation approach and multi-linear model. The applicability of the proposed approach is validated and the effects of complicated characteristics of structure and soil on soil-structure interaction are investigated through the numerical example by the proposed nonlinear soil-structure interaction analysis approach.

Earthquake Response Analysis considering Irregular Soil Layers (불규칙한 다층 물성을 가지는 지반의 지진 응답 해석)

  • Park, Jang-Ho;Park, Jae-Gyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.9 no.6
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    • pp.67-73
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    • 2005
  • Precise analysis of soil-structure interaction requires a proper description of soil profile. However, such approach becomes generally nearly unpractical for soil exhibiting material discontinuity and complex geometry since meshes should match that material discontinuity line. To overcome these difficulties, a different numerical integration method is adopted in this paper, which enables to integrate easily over an element with material discontinuity without regenerating mesh fellowing the discontinuity line. As a result the mesh is highly structured, loading to very regular silliness matrix. The influence of the shape of soil profile on the response is examined and it is seen that the proposed soil-structure analysis method can be easily used on soil-structure interaction problems with complicated soil profile and produce reliable results regardless of material discontinuities.

Dynamic Analysis of Soil-Pile-Structure Interaction Considering a Complex Soil Profile (복잡한 지반층을 고려한 지반-말뚝-구조물의 상호작용 동해석)

  • Park, Jang-Ho;Park, Jae-Gyun
    • Journal of the Earthquake Engineering Society of Korea
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    • v.13 no.3
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    • pp.21-28
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    • 2009
  • The precise analysis of soil-pile-structure interaction requires a proper description of soil layer, pile, and structure. In commonly used finite element simulations, mesh boundaries should match the material discontinuity line. However, in practice, the geometry of soil profiles and piles may be so complex that mesh alignment becomes a wasteful and difficult task. To overcome these difficulties, a different integration method is adopted in this paper, which enables easy integration over a regular element with material discontinuity regardless of the location of the discontinuity line. By applying this integration method, the mesh can be generated rapidly and in a highly structured manner, leading to a very regular stiffness matrix. The influence of the shape of the soil profile and piles on the response is examined, and the validity of the proposed soil-pile structure interaction analysis method is demonstrated through several examples. It is seen that the proposed analysis method can be easily used on soil-pile-structure interaction problems with complex interfaces between materials to produce reliable results regardless of the material discontinuity line.

Reliability-Based Analysis of Slope Stability Due to Infiltration (침투에 대한 불포화 사면의 신뢰성 해석)

  • Cho, Sung-Eun;Lee, Jong-Wook;Kim, Ki-Young;Jeon, Je-Sung
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.649-654
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    • 2005
  • Shallow slope failures in residual soil during periods of prolonged infiltration are common over the world. One of the key factors that dominate slope stability is hydrological response associated with infiltration. Hence, the soil-water profile during rainfall infiltration into unsaturated soil must me examined to evaluate slope stability. However, the hydraulic response of unsaturated soil is complicated by inherent uncertainties of the soil hydraulic properties. This study presents a methodology for assessing the effects of parameter uncertainty of hydraulic properties on the response of a analytical infiltration model using first-order reliability method. The unsaturated soil properties are considered as uncertain variables with means, standard deviations, and marginal probability distributions. Sensitivities of the probabilistic outcome to the basic uncertainties in the input random variables are provided through importance factors.

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Capillary Bundle Model for the Estimation of Air-water Interfacial Area and the Gas-filled Pore Size Distribution in Unsaturated Soil (모세관 모델을 이용한 불포화토양의 물-가스 접촉면적 및 가스공극 크기분포의 계산 및 검증)

  • Kim, Heonki
    • Journal of Soil and Groundwater Environment
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    • v.26 no.1
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    • pp.1-7
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    • 2021
  • Air-water interfacial area is of great importance for the analysis of contaminant mass transfer processes occurring in the soil systems. Capillary bundle model has been proposed to estimate the specific air-water interfacial areas in unsaturated soils. In this study, the measured air-water interfacial areas of a soil (loam) using the gaseous interfacial tracer technique were compared to those from capillary bundle model. The measured values converged to the specific solid surface area (7.6×104 ㎠/㎤) of the soil. However, the simulated air-water interfacial areas based on the capillary bundle model deviated significantly from those measured. The simulated values were substantially over-estimated at low end of the water content range, whereas the model under-estimated the air-water interfacial area for the most of the water content range. This under-estimation is considered to be caused by the nature of the capillary bundle model that replaces the soil pores with a bundle of glass capillaries and thus no surface roughness at the inner surface of the capillaries is taken into account for the estimation of the air-water interfacial area with the capillary bundle model. Subsequently, appropriate correction is necessary for the capillary bundle model to estimate the air-water interfacial area in soils. Since the soil-moisture release curve data is the basis of the capillary bundle model, the model can be of use due to its simplicity, while the gaseous tracer technique requires complicated experimental equipment followed by moment analysis of the breakthrough curves. The size distribution profile of the pores filled with gas estimated by the water retention curve was found to be similar to that of particle size at different size range. The shifted distribution of gas-filled pores toward smaller size side compared to the particle size distribution was also found.

Characterization of Ferrallitique Soils (Ferrallitique토양(土壤)의 특성(特性)에 관(關)한 연구(硏究))

  • Sin, Cheon-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.18 no.3
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    • pp.260-264
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    • 1985
  • Ferrallitique soils are real tropical soils, with an oxic B horizon such a horizon is at least 30cm thick, has > 15% clay, diffuse horizon boundaries, no weatherable minerals and a CEC of clay < 16 me per 100g. These soils are in general the real reddish or yellowish very uniform tropical clay soils with an orchric A horizon and a deep B horizon, otherwise almost characterless. The soil profile looks uniform and maybe some metres thick. It is well drained, has a good permeability and a stable structure. As there is little or no weatherable mineral, because these soils are old and exhausted of bares, natural fertility is very low. There has been a complicated process of soil formation. Intensive and continuous weathering over a very long period has resulted in leaching of bases and silica, in relative accumulation of resquioxides and in formation of kaolinitic clay. Until recently, there has been much confusion in classifing and naming tropical soils. Particularily what are now Ferralsols in the FAO scheme, and Oxisols in Soil Taxonomy. Old names of various classification system are: Lateritic soils, Latosols, Ferrallitic soils. For agriculture, these soils are important, but chemically very poor, not only because of a low CEC but also because of deficiency of bases, especially Ca, Mg, and K, strong P fixation and high exchangeable Al percentage.

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GIS for Subsidence Analysis by Considering Surface Condition (지표면의 조건을 고려한 지반침하 분석용 GIS)

  • 권광수;이준용;박형동
    • Economic and Environmental Geology
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    • v.34 no.6
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    • pp.595-600
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    • 2001
  • Recently, interests in subsidence hazard have been increased due to the underground construction such as subway construction and managements of abandoned mines. GIS analysis of subsidence hazard has a lot of advantages in handling of spatial data and managing database. For better result of GIS analysis, there are some necessities of modifying previous subsidence theory and model. To take surface profile into account allows the application of complicated topology. Furthermore. for 3-dimensional analysis. two subsidence profile curves that are perpendicular to each other should be considered simultaneously. Through these modifications, the model for subsidence analysis using GIS can be established. With ideal case of cavities and other conditions, GIS analysis was accomplished and meaningful results were produced. More realistic properties of cavity. soil layers, groundwater condition and topology will enable GIS analysis method to produce more reliable result and to widen the area of applications.

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Diversity of Bradyrhizobium japonicum with Different Colony Morphology in Intrinsic Antibiotic Resistance, Serological Property, and Protein Profile (콩 근류균(根瘤菌) Bradyrhizobium japonicum의 취락형태별(聚落形態別) 항생제(抗生劑) 반응(反應)과 혈청형(血淸型) 및 단백질전기영동(蛋白質電氣泳動) 유형(類型)의 다양성(多樣性))

  • Kang, Ui-Gum;Ha, Ho-Sung;Jung, Yeun-Tae;Kang, Hang-Won;Yun, Han-Dae;Ha, Yeong-Lae
    • Korean Journal of Soil Science and Fertilizer
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    • v.29 no.1
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    • pp.60-66
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    • 1996
  • Bradyrhizobium japonicum with different colony morphology populated in five Yeongnam soils of Korea was examined for intrinsic antibiotic resistance to eight antibiotics, serological property by immunoblot and immunodiffusion, and protein profile differentiation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Colony morphological distribution of one hundred and twenty B. japonicum isolates was 47% for "dry". 41% for "wet", and 12% for "dry/wet" type. The total isolates showed such a strong correlation between the morphology and antibiotic resistance. Colony morphology, which though was dominantly consisted of the same type within a serogroup, wasn't absolutely linked to serological property of B. japonicum. Based on these data, colony morphology was too simple to identify variations with B. japonicum isolates : antibiotic resistance such complicated compared with serological analyses.

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