• 제목/요약/키워드: soil condition

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일반 시설물의 지반-구조물 상호작용 해석 기준에 대한 고찰 (Overview on Standards for Soil-Structure Interaction Analysis used in Design of Infrastructure)

  • 김현욱;하정곤;김동수;주광호
    • 한국지진공학회논문집
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    • 제21권5호
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    • pp.227-236
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    • 2017
  • This study reviews concepts, theories and formulas included in standards on soil-structure interaction and also shows practical example of application for engineers. Real structures are 3 dimensional and multi degree of freedom but they are often idealized to single degree of freedom for convenience. In this study, detailed procedures to calculate soil spring constants and damping coefficients and method to model soil-structure system are explained. Additionally, case studies to judge fixed base condition and evaluation of applicability of simple analysis method based on response spectra are performed.

Spherical cavity expansion in overconsolidated unsaturated soil under constant suction condition

  • Wang, Hui;Yang, Changyi;Li, Jingpei
    • Geomechanics and Engineering
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    • 제29권1호
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    • pp.1-11
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    • 2022
  • A semi-analytical solution to responses of overconsolidated (OC) unsaturated soils surrounding an expanding spherical cavity under constant suction condition is presented. To capture the elastoplastic hydro-mechanical property of OC unsaturated soils, the unified hardening (UH) model for OC unsaturated soil is adopted in corporation with a soil-water characteristic curve (SWCC) and two suction yield surfaces. Taking the specific volume, radial stress, tangential stress and degree of saturation as the four basic unknowns, the problem investigated is formulated by solving a set of first-order ordinary differential equations with the help of an auxiliary variable and an iterative algorithm. The present solution is validated by comparing with available solution based on the modified Cam Clay (MCC) model. Parametric studies reveal that the hydraulic and mechanical responses of spherical cavity expanding in unsaturated soils are not only coupled, but also affected by suction and overconsolidation ratio (OCR) significantly. More importantly, whether hydraulic yield will occur or not depends only on the initial relationship between suction yield stress and suction. The presented solution can be used for calibration of some insitu tests in OC unsaturated soil.

Cu, Pb, As 복합 중금속오염 토양의 전기동력학적 정화에서 전해질의 영향 평가 (Evaluation of Processing Fluids on Electrokinetic remediation of Cu, Pb, As-contaminated soil)

  • 박근용;김도형;백기태
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제15권5호
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    • pp.1-7
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    • 2010
  • Electrokinetic technology was applied to remediate Cu, Pb and As-contaminated paddy soil. Removal of metal is highly dependent on the processing fluid during electrokinetic treatment. Tap water, NaOH, $HNO_3$, $Na_2EDTA$, and citric acid were evaluated as the processing fluids to enhance metal removal. Cu and Pb were transported toward cathode, however, it did not removed from soil section, while 56.6% of As was removed at a acidic condition. The strong acidic condition with nitric acid as a processing fluid enhanced the desoprtion of As from soil surface. However, longer operation time is needed to get the higher removal of Cu and Pb, and the acidification of soil after electrokinetic treatment should be solved.

Seismic evaluation of soil-foundation-structure interaction: Direct and Cone model

  • Khazaei, Jahangir;Amiri, Azadeh;Khalilpour, Mehrdad
    • Earthquakes and Structures
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    • 제12권2호
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    • pp.251-262
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    • 2017
  • The present research intends to study the effects of the seismic soil-foundation-structure interaction (SFSI) on the dynamic response of various buildings. Two methods including direct and Cone model were studied through 3D finite element method using ABAQUS software. Cone model as an approximate method to consider the SFSI phenomenon was developed and evaluated for both high and low rise buildings. Effect of soil nonlinearity, foundation rigidity and embedment as well as friction coefficient between soil-foundation interfaces during seismic excitation are investigated. Validity and performance of both approaches are evaluated as reference graphs for Cone model and infinite boundary condition, soil nonlinearity and amplification factor for direct method. A series of calculations by DeepSoil for inverse earthquake record modification was conducted. A comparison of the two methods was carried out by root-mean-square-deviation (RMSD) tool for maximum lateral displacement and story shear forces which verifies that Cone model results have good agreement with direct method. It was concluded that Cone method is a convenient, fast and rather accurate method as an approximate way to count for soil media.

시공조건이 시멘트계 고화토의 투수계수에 미치는 영향 (Effects of Some Construction Variables on the Hydraulic Conductivity of Soil-Cement in Low Permeable Applications)

  • 정문경;김강석;우제윤
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 가을 학술발표회 논문집
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    • pp.427-434
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    • 2000
  • Hydraulic conductivity of soil-cement was measured as a function of some selected construction variables that are often encountered in practice. They are initial (or compaction) water content, delayed compaction after mixing, and repeated freezing and thawing. Sandy and clayey soils were used. The hardening agent used was a cement based soil stabilizer consisting of 80% of ordinary Portland cement and 20% of a combination of supplementary materials. Hydraulic conductivity of soil-cement with varying initial water content was, in trend, similar to that of compacted clay. Hydraulic conductivity of soil-cement decreased with increasing initial water content and reached its minimum when compacted wet of optimum water content. Pore size distributions of soil cement at different initial water contents were analyzed using mercury intrusion porosimetry. The analysis showed that dryer condition led to the formation of larger pores with lesser total pore volume; smaller pores with larger total pore volume at wetter condition. Hydraulic conductivity of soil-cement increased by orders in magnitude when specimen underwent delayed compaction of longer than 4 hours after mixing and repeated freezing and thawing.

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간접열탈착방식을 이용한 원유오염토양 정화효율 평가 (The Study of Crude Oil Contaminated Soil Remediation by Indirect Thermal Desorption)

  • 이인;김종성;정태양;오승택;김국진
    • 한국지하수토양환경학회지:지하수토양환경
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    • 제21권3호
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    • pp.14-20
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    • 2016
  • Remediation of crude oil contaminated soil is complicate and hard to apply traditional methods because of its persistency, durability, and high viscosity. Therefore, in this study, the efficiency of crude oil contaminated soil remediation was tested by developing a pilot-scale thermal desorption system using the indirect heating method with an exhaust gas treatment. Under optimal condition drawed by temperature and retention time, the remedial efficiency of crude oil contaminated soil and treatability of exhaust gas were analyzed. Total Petroleum Hydrocarbon (TPH) concentration of crude oil contaminated soil was decreased to 69.7 mg/kg on average and the remedial efficiency was measured at 99.60%. Through the exhaust gas, 86.0% of Volatile Organic Compounds (VOC) was degraded and 97.16% of complex malodor was reduced under the suggested optimum operation condition. This study provides important basic data to be useful in scaling up of the indirect thermal desorption system for the remediation of crude oil contaminated soil.

전전환답 포장에서의 지하수위 및 토양수분 변화 특성 (Variational Characteristics of Water-Table and Soil Moisture in Paddy-Upland Rotational Fields)

  • 권순국;윤경섭
    • 한국농공학회지
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    • 제36권2호
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    • pp.123-131
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    • 1994
  • Experimental studies were conducted to make clear the soil moisture environment under the condition of paddy-upland rotational fields by investigating water-table depths and soil moisture contents during growing season of crops in two kinds of soil. The following results were obtained. 1.Although water-table depths fluctuated with the amount of rainfall in the experimental field, it seemed that the variation of vater4able depths in the paddy-upland rotational, field was strongly affected by the condition of locations on paddy fields. 2.It is recognized that the concept of sum of excess water depth(SEWxx) and sum of excess water day(SEDxx) can be used to represent the soil moisture stress index due to the fluctuation of water-table depths. 3.The results of this study clearly indicate that drainage in paddy-upland rotational field to maintain an optimum soil moisture content must be made by introducing the concept of block drainage which needs both subsurface drainage and intercept drainage around a field. 4.Soil moisture contents were affected by both the amount of rainfall and water-table depths, however, the moisture content for top soil showed higher correlation with the amount of rainfall while that for subsoil with water-table depths.

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Analysis of Mobile Lead in Soil Using Carboxylated Magnetic Particle

  • So, Hyung-Suk;Shin, Hyun-Chul;Yoo, Yeong-Seok;Schaeffer Andreas
    • Journal of Magnetics
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    • 제10권3호
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    • pp.89-92
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    • 2005
  • The analytic possibility of mobile lead contained in soil has been studied using carboxylated magnetic beads. Extraction of heavy metal was performed to contaminated soil that has been collected and supplied for tests. As experiment materials, soil sample, distilled water and magnetic beads were only used. It means that the lead was extracted under neutral condition. In this condition, only the mobile fraction of lead could be extracted by magnetic beads. The mobile lead in the soil was quickly combined with magnetic beads in the mixture process. Then, the magnetic beads were dissolved into acids after collection by external magnetic force, and the lead combined with the beads was eluted and analyzed by Graphite Furnace Atomic Absorption Spectroscopy (GFAAS). In the results of extraction experiments for 3 sandy soils, the efficiency using beads was similar to or higher than that of EDTA (Ethylendiamintetraacetic acid), which is normally used for analyzing mobile heavy metal concentration in soil. With this, it was shown that this method is a more accurate and simple method to analyze mobile lead when analyzing mobile heavy metal concentration in sandy soil, rather than conventional method using EDTA.

Isolation of Bacillus sp. SHL-3 from the Dry Soil and Evaluation of Plant Growth Promoting Ability

  • Hong, Sun Hwa;Kim, Ji Seul;Sim, Jun Gyu;Lee, Eun Young
    • 한국토양비료학회지
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    • 제48권1호
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    • pp.36-43
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    • 2015
  • Excess use of chemical fertilizer causes soil acidification and accumulation of salt, and thus might bring to desertification of soil. To overcome this problem, it needs limited usage of chemical fertilizer and increased usage of natural fertilizer as an alternative. In this study, dry soil-borne Bacillus sp. SHL-3, which was isolated from arid and barren soil, with plant growth promoting activity was isolated for identification and to determine optimal culture condition. A bacterial strain SHL-3 had the IAA productivity ($5.16{\pm}0.10mg\;L^{-1}$), ACC deaminase activity ($0.36{\pm}0.09$ at 51 hours) and siderophore synthesis. It was identified as genus Bacillus sp.. Also, optimal culture condition of SHL-3 were $20^{\circ}C$ and pH 7 in LB medium. Bacillus sp. SHL-3 had up to 4% salt tolerance in the medium. We evaluated the plant growth promotion ability of SHL-3 using yam (Dioscorea japonica Thunb.). As a result, Bacillus sp. SHL-3 was effective on the increase of the shoot length (202.4% increase for 91 days). These results indicate that Bacillus sp. SHL-3 can serve as a promising microbial resource for the biofertilizers of soil.

USGA 공법으로 조성된 그린의 토앙물리성과 Bentgrass의 생육 (Turfgrass Establishment of USGA Putting Greens Related with Soil Physical Properties)

  • 권동영;이정호;이동익;주영규
    • 아시안잔디학회지
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    • 제19권2호
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    • pp.95-102
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    • 2005
  • USGA green specification is currently accepted in construction method of Korea. This study was carried out to find the factors influencing growth of turfgrass associated with soil physical properties of soil root-zone on golf green constructed with USGA method. Three putting greens in poor turfgrass and one in good turfgrass condition were selected for investigation on one golf course site at mid-South Korean peninsula. Soil hardness, moisture content, root length, and turf density were measured on-site greens, and soil physical properties and soil chemical properties also analyzed in laboratory. As a result of on-site surveys and soil physical tests in laboratory, soil physical properties were most important factors which influenced on turfgrass growth at tested greens. The results of soil particle analysis on green No. 2, in good turf condition, matched USGA sand particle recommendations. But those greens such as Nos. 1, 11 and 16, in poor putting greens, showed high soil compaction and improper soil particle distribution. Those factors created low leaf density, poor root depth, and higher moisture content compared with lower part of topsoil. Such phenomena caused inadequate turfgrass growth with soil hardening associated with poor drainage. Therefore, declines of soil physical properties associated with improper particle distribution caused a major factor influencing on turfgrass growth in golf green. Adequate test of soil particle analysis by USGA specification and proper construction method followed by adequate turf maintenance should be performed to obtain optimal turf quality on putting green.