• Title/Summary/Keyword: soil strain

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Evaluation and Application of Dynamic Soil Properties for SSI Analysis (지반-구조물 상호작용해석시 동적지반특성의 평가 및 적용)

  • Lee, Myung Jae;Shin, Jong Ho;Chon, Chun Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.2
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    • pp.103-112
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    • 1990
  • This study examines the characteristics of soil behavior which includes many uncertainties in seismic design, evaluates the dynamic soil properties and studies the soil-structure interaction to generalize the applicability and economy of the available sites. An example analysis is performed for soil-structure system response assuming a containment structure built on site which includes soil layers using both elastic halfspace analysis and FEM analysis against the seismic loads from the actual design. This exercise is performed as a part of the safety analysis and economic assessment of the nuclear power plant built on soils. It includes the preparation of computer program capable of incorporating large nonlinearity in the analysis, resonable evaluation procedures to determine input soil data. Nonlinear FEM analysis of Seed and Idriss model is found suitable for the accurate analysis of dynamic response of soils. Linear FEM analysis using dynamic soil properties at strain level obtained by one-dimensional seismic response, and elastic half-space analysis using dynamic soil properties at strain level under static loads are recommended to evaluate the dynamic soil properties.

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Inducing stress-strain relationship for element simulation of cyclic triaxial test on unsaturated soil (불포화토에 대한 반복삼축압축시험의 요소시뮬레이션을 위한 응력-변형율 관계의 수립)

  • Lee, Chung-Won
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.8
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    • pp.5654-5663
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    • 2015
  • In the unsaturated soil, suction, the negative pore water pressure leads to increases of the yield stress and the plastic shear stiffness of the soil skeleton due to the growth in interparticle stress. Therefore, in this study, the stress-strain relationship based on cyclic elasto-plastic constitutive model extended for unsaturated soil considering the 1st and the 2nd yield functions was induced in order to account for these effects of suction under the dynamic loading condition such as the earthquake. Through the program code considering this relationship and the routine of the cyclic loading with the reversion of loading direction, the numerical simulation of the cyclic triaxial test under the unsaturated condition would be possible. It is expected that the results of this study possibly contribute to the accuracy improvement on the prediction of unsaturated soil behavior under the dynamic loading condition.

The behavior of a Cut Slope Stabilized by Use of Piles during Heavy Rain (억지말뚝으로 보강된 절개사면의 강우시 거동)

  • Han, Jung-Geun;Hong, Won-Pyo;Sin, Min-Ho
    • Geotechnical Engineering
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    • v.12 no.1
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    • pp.35-46
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    • 1996
  • An instrumentation system is designed to observe the behavior of slope soil and stabilizing piles during heavy rains. Inclinometers, standpipe piezometers and strain gages are installed into a cut slope reinforced by a row .of piles for an apartment. The horizontal deflection and bending stress developed on the piles can be measured, respectively, by the inclinometers and strain gages installed in piles, while the horizontal deformation of the slope soil can be measured by the inclinometer installed in the soil across the open space between piles. The groundwater level doss not grow so sensitively during heavy rain. The behavior of piles and slope is 서footed by the wetting front, since the driving force of slope increases with the weight of slope soil above the wetting front. The stabilizing piles and the slope soil show elastic behavior during heavy rain.

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An Analysis of the Internal Deformation Behaviors of Geosynthetic Reinforced Soil Walls used Clayey Soil as Backfills (뒤채움재로 점성토를 사용한 보강토벽의 내적 거동 분석)

  • Kim, Heung-Ki;Kim, You-Seong
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.2
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    • pp.39-49
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    • 2005
  • In this study, the fifteen month behavior of two geosynthetic reinforced walls which was constructed on the shallow weak ground was measured and analyzed. The walls were backfilled with clayey soil obtained from the construction site nearby, and the safety factors obtained from general limit equilibrium analysis were less than 1.3 in both wall. The measured and analyzed data were horizontal earth pressures, strain of reinforcements, and excess pore water pressures. The used reinforcements were nonwoven geotextile, woven geotextile and geogrid. Although the length of reinforcement was only 30% of wall height and the safety factors of the walls were less than 1.3, the walls were constructed without any problems on the such weak ground. The analysis results showed that the maximum strain of reinforcements were negligible and the strain was between 2.3 and 6.0% according to tensile characteristic of the reinforcements. The excess pore water pressure was not changed due to the rainfall and the horizontal earth pressures in upper and lower part of the walls were larger than the active and the rest pressure.

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Diversity and Phylogenetic Analysis of Fluorescent Pseudomonads Isolated from Soil-Root System of Red Pepper in Greenhouse (비닐하우스 고추재배지의 토양과 근계로부터 분리된 형광성 Pseudomonads의 계통 분류 및 다양성)

  • Kwon, Soon-Wo;Kim, Jong-Shik;Song, Jae-Kyeong;Ryu, Jin-Chang
    • Korean Journal of Soil Science and Fertilizer
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    • v.33 no.4
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    • pp.275-282
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    • 2000
  • Among the fluorescent pseudomonad isolates from soil- root system of red pepper in Chinju, Kyunsangnam-Do, the phylogenetic analysis for 35 isolates were conducted. The partial 16S ribosomal DNA sequences were used as taxonomic key for phylogenetic analyses, and these sequences were enabled to identification of the fluorescent pseudomonad isolates on the species level. The 17 isolates among them were classified into Pseudomonas putida group, and consisted of the strains isolated mainly from soil. This group were subdivided into 4 subgroups (I, II, III, and IV). The subgroup I and IV were unique ones which were relatively remotely related with subgroup II and III including the type strain of P. putida. The 15 isolates among 35 isolates were grouped along with the type strain of Pseudomonas fluorescens, and 3 isolate were characterized as intermediates of P. fluorescens and Pseudomonas chlororaphis. Most of strain isolateds from the rhizosphere soil and rhizoplane of red pepper were identified as P. fluorescens and closely related with each other. In this study, root of red pepper was supposed to be colonized by a specific strain or strains of P. fluorescens.

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A Constitutive Model on the Behavior under $K_0$ Condition for Weathered Soils. (풍화토의 $K_0$ 조건하 거동에 대한 구성모델)

  • Oh, Se-Boong;Kim, Wook;Jeong, Gahng-Bok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2003.03a
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    • pp.169-174
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    • 2003
  • Undrained triaxial tests were performed under $K_{0}$ condition for a weathered soil, which includes local measurement using LVDT. An anisotropic hardening model based on effective stress concept could predict the stress-strain relationship under $K_{0}$ condition reasonably, which makes it possible to analyze geotechnical problems for the weathered soil.

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Sporothrix stylites : A New Record from Field Soil in Korea

  • Park, Sangkyu;Lee, Seung-Yeol;Back, Chang-Gi;Kang, In-Kyu;Ten, Leonid;Lee, Hyang Burm;Jung, Hee-Young
    • The Korean Journal of Mycology
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    • v.45 no.3
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    • pp.224-228
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    • 2017
  • The fungal strain, designated KNU16-008, was isolated from field soil in Chungcheongnam-do, Korea. The isolated fungi was characterized by morphological and phylogenetic analyses. Isolated fungus showed typical morphological characteristics of the genus Sporothrix. Based on its phylogenic analysis using internal transcribed spacer (ITS) of rDNA and ${\beta}$-tubulin gene sequences, the strain KNU16-008 was identified as Sporothrix stylites. This species has not been previously reported in Korea.

Isolation and Identification of Methylotrophic Actinomycetes capable of Producing Anti-oral Cancer Activity (구강암에 대해 항암효과를 나타내는 methanol 자화 방선균의 분리 및 동정)

  • Kim, Jung;Kim, Sun-Sook
    • Journal of Korean society of Dental Hygiene
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    • v.1 no.2
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    • pp.193-200
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    • 2001
  • An appropriate amount of samples, collected from three each paddy forest, field and riverside soil near Taegu city, was suspended in sterile water and then diluted in order to isolation of antagonistic to oral cancer. The diluted samples were inoculated on separating medium in the routing spreading method. So, seven hundred and eighteen strains were isolated on HV agar and 220 strains were on methanol medium from soil samples. So, during the screening of anti-oral cancer activity from soil, we isolated microorganisms showing powerful antagonistic activity. Among them, No. 78 strain exhibited the most strongly anti-oral cancer activity. Microbiological properties were investigated by the methods described in the Bergey's Manual of Systematic Bacteriology and experimental methods of identification of actinomycetes by Hamada et al. As a result, a methylotrophic actinomycetes strain No. 79 was estimated as Amycolatopsis sp. based on taxonomic studies.

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Strain localization and failure load predictions of geosynthetic reinforced soil structures

  • Alsaleh, Mustafa;Kitsabunnarat, Akadet;Helwany, Sam
    • Interaction and multiscale mechanics
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    • v.2 no.3
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    • pp.235-261
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    • 2009
  • This study illustrates the differences between the elasto-plastic cap model and Lade's model with Cosserat rotation through the analyses of two large-scale geosynthetic-reinforced soil (GRS) retaining wall tests that were brought to failure using a monotonically increasing surcharge pressure. The finite element analyses with Lade's model were able to reasonably simulate the large-scale plane strain laboratory tests. On average, the finite element analyses gave reasonably good agreement with the experimental results in terms of global performances and shear band occurrences. In contrast, the cap model was not able to simulate the development of shear banding in the tests. In both test simulations the cap model predicted failure loads that were substantially less than the measured ones.

ASSESSMENT OF TUNNELLING-INDUCED BUILDING DAMAGE

  • Son, Moo-Rak
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09c
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    • pp.86-95
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    • 2010
  • Ground movements during tunnelling have the potential for major impact on nearby buildings, utilities and streets. The impacts on buildings are assessed by linking the magnitude of ground loss at the source of ground loss around tunnel to the lateral and vertical displacements on the ground surface, and then to the lateral strain and angular distortion, and resulting damage in the building. To prevent or mitigate the impacts on nearby buildings, it is important to understand the whole mechanism from tunnelling to building damage. This paper discusses tunneling-induced ground movements and their impacts on nearby buildings, including the importance of the soil-structure interactions. In addition, a building damage criterion, which is based on the state of strain, is presented and discussed in detail and the overall damage assessment procedure is provided for the estimation of tunnelling-induced building damage considering the effect of soil-structure interaction.

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