• Title/Summary/Keyword: Consolidation effect

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Safety Assessment of Embankment by Analysis of Electrical Properties (전기비저항 물성 분석을 통한 제체의 안정성 검토)

  • Oh, Seok-Hoon;Suh, Baik-Soo
    • The Journal of Engineering Geology
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    • v.18 no.3
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    • pp.245-255
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    • 2008
  • The variation of the electrical property of embankment material was analyzed from laboratory experiments and the result of field survey, in order to enhance the interpretation of electrical resistivity survey frequently used for safety assessment of embankment. At first, the kaolinite, showing similar physical property with core material of embankment, was used to examine the variation of the resistivity value according to degree of consolidation. The test showed that a drop of shear strength induces increase of resistivity value regardless of degree of water content. This result means that porous zones of weak core material in embankment may be appeared as highly resistive part in the electrical resistivity survey. This observation implies that it may fail to detect weak core material by electrical method, if we only try to and zones showing low resistivity value. And, we performed Standard Penetration Test (SPT) to analyze the correlation between electrical property and ground stiffness. Finally, a mechanism to describe the variation of electrical resistivity due to grouting effect was proposed and real field data were analyzed.

Laboratory/In situ Sound Velocities of Shelf Sediments in the South Sea of Korea

  • Kim, Dae-Choul;Kim, Gil-Young;Jung, Ja-Hun;Seo, Young-Kyo;Wilkens, Roy H.;Yoo, Dong-Geun;Lee, Gwang-Hoon;Kim, Jeong-Chang;Yi, Hi-Il;Cifci, Gunay
    • Fisheries and Aquatic Sciences
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    • v.11 no.2
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    • pp.103-112
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    • 2008
  • Compressional sound velocities of shelf sediments in the South Sea of Korea, were measured in situ and in the laboratory for six cores. In situ sound velocity was measured using the Acoustic Lance (frequency of 7.5-15 kHz), while laboratory velocity was measured by the pulse transmission technique (frequency of 1MHz). Physical properties were relatively uniform with sediment depth, suggesting little effect of sediment compaction and/or consolidation. Average in situ velocity at each core site ranged from 1,457 to 1,488 m/s, which was less than the laboratory velocity of 1,503 and 1,604m/s. In muddy sediments the laboratory velocity was 39-47 m/s higher than in situ velocity. In sandy sediments, the difference was greater by an average of 116 m/s. Although the velocity data were corrected by the velocity ratio method based on bottom water temperature, the laboratory velocity was still higher than the in situ velocity (11-21 m/s in muddy sediments and 91 m/s in sandy sediments). This discrepancy may be caused by sediment disturbance during core collection and/or by the pressure of Acoustic Lance insertion, but it was most likely due to the frequency difference between in situ and laboratory measurement systems. Thus, when correcting laboratory velocity to in situ velocity, it is important to consider both temperature and frequency.

The Effects of Adolescents' Experiences of Abuse Damage on Aggressiveness in the Convergence Era: Focused on the Mediation Effects of Resilience (청소년의 학대피해경험이 공격성에 미치는 영향: 자아탄력성의 매개효과)

  • Kim, Sug-Hyang;Kim, Hyung-Mo
    • Journal of the Korea Convergence Society
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    • v.9 no.2
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    • pp.331-340
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    • 2018
  • The purpose of this study is to verify resilience's mediation effects in the effects of adolescents' experience of abuse damage on aggressiveness in the convergence era. Towards this end, this study used the 7th year data (2016) (4th grade to the first year of high school) of Korea Children & Youth Panel Survey (KCYPS). The findings of this study are as follows: First, the correlations between experience of abuse damage, aggressiveness, and resilience variables were confirmed using multicollinearity VIF values. Second, adolescent's abuse experiences significantly affected their aggressiveness. Third, the partial mediation effects of resilience were shown in the effects of adolescents' experience of abuse damage on their aggressiveness. For the verification of mediation effects' significance, the Sobel test was carried out. The findings of this study are meaningful, as this study provides empirical data. Based on the findings, this study proposed the need of resilience consolidation programs for adolescents in the practice of social welfare.

A Study on Mechanical Properties of High Strength Concrete Performed by Full Scaled Mock-up Test (1:1 실부재 Mock-up Test를 통한 고강도 콘크리트의 역학적 특성에 관한 연구)

  • Moon, Hyung-Jae;Seok, Won-Kyun;Park, Soon-Jeon;Lee, Joo-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.981-984
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    • 2008
  • The super tall building above 100 floors is required that each floor's height is more than 4 meters, and each core wall's thickness is more than 60cm. Therefore, for the successive accomplishment of super tall building, the full scale mock-up test was required. The test results are as follows; Real strength of core wall was satisfied with design strength at 28 days regardless of types of strength, and according to the consolidation effect, lower part's strength was a little higher than upper part's strength. Lateral force of HSC was evaluated with max. $4.5ton/m^2$, and hydration temperature of mock-up test was evaluated that maximun heat of central part revealed about $80^{\circ}C$ at 70MPa and $65^{\circ}C$ at 50MPa, and, the difference between inner and outter part revealed about $30^{\circ}C$ at 70MPa and $12^{\circ}C$ at 50MPa. Also, no crack by hydration temperature was not shown on the surface.

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A Case of Diffuse Alveolar Hemorrhage with Glomerulonephritis after Propylthiouracil Treatment (Propylthiouracil 복용 후 발생한 사구체신염이 동반된 미만성 폐출혈 1예)

  • Lee, Ji-Hyun;Kim, Min-Su;Lee, Jae-Gon;Kim, Dae-Sik;Yang, Hae-Jin;Kang, Kyung-Woo
    • Tuberculosis and Respiratory Diseases
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    • v.72 no.1
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    • pp.93-97
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    • 2012
  • Propylthiouracil (PTU) is one of the most common drugs used in the treatment of Graves' disease. There are a number of side effects found with PTU use including fever, rash, arthralgia, and flu-like symptoms. Recently antineutrophil cytoplasmic antibodies (ANCA) positive vasculitis after PTU treatment was reported as a rare side effect, which can cause diffuse alveolar hemorrhage and glomerulonephritis. A 45-year-old woman with Graves' disease had been treated with PTU for five months, complained of hemoptysis due to pulmonary alveolar hemorrhage causing anemia, and also had hematuria. Simple chest X-ray and HRCT showed bilateral consolidation and bronchoalveolar lavage fluid revealed alveolar hemorrhage. A serologic test was positive for ANCA against myeloperoxidase and proteinase-3. Such findings suggested that the presence of PTU induced ANCA positive vasculitis. Cessation of PTU and the administration of high dose steroids improved the clinical manifestation, radiologic and serologic findings. We observed ANCA titer serially for 6 years. During the follow up period, ANCA titer decreased slowly and stayed within the acceptable upper normal limit.

Finite Element Modeling of Geogrid-encased Stone Columns in Soft Clay (지오그리드 보강 쇄석 말뚝 공법의 유한요소해석 모델링)

  • Yoo, Chung-Sik;Song, Ah-Ran;Lee, Dae-Young;Kim, Sun-Bin;Park, Si-Sam
    • Journal of the Korean Geosynthetics Society
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    • v.6 no.1
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    • pp.17-25
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    • 2007
  • This study presents a modeling approach for geogrid-encased stone column(GESC) method which is widely used in Europe as an alternative to conventional pile foundations. Several benefits of using the stone column method include sound performance, low cost, expediency of construction, and liquefaction resistance, among others. Recently, geosynthetic-encased stone column approach has been developed to improve load carrying capacity through increasing confinement effect. The aim of this research is to establish a systematic approach for modeling of GESC and to form a database for the fundamentals of GESC. This paper presents details of 3D modeling of GESC together with the general behavior of GESC.

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Development of Campus-Wear Product Design that Utilizes UI - A Case Study of G National University - (UI를 활용한 캠퍼스의류 상품디자인 개발 - G 국립대학교의 사례를 중심으로 -)

  • Um, So-Hee;Kim, Nan
    • The Research Journal of the Costume Culture
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    • v.20 no.1
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    • pp.83-98
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    • 2012
  • In 2009, two national universities were integrated into one and the following was newly named Gangneung- Wonju National University. Therefore, this university requires consolidation and promotion of UI(University Identity) as a college brand in order to secure and enhance its competitiveness. The purpose of this study was to design and develop campus-wear, ultimately, it can be used as a part of the Gangeung-Wonju University's UIP policy. A qualitative approach of searching==incorporating books, dissertations, and web-based information==was taken to investigate theoretical backgrounds. The campus-wears were collected from the selected universities in Korea and abroad for the distinct design development. The result of the research are as follows. The concept for the design planning was "wit, exciting & challenge for campus life". The developed UI had focused on expressing positive images of the University. Six items were chosen for the campus-wear design. The goal was to demonstrate practicality and fashion trend. The color arrangement primarily focused on the University's official color and pursued a bright, breeze look. The detailed techniques used for the actual production were printing, embroidery, and accessories. The UI products may not only instill the members of the university with the spirit and pride by strengthening the sense of belonging, but also create a synergistic effect in education by boosting the university promotion and by newly establishing standing as the integrated university.

Influences of Confining Pressure and Fines Content on Compressibility Characteristics of Sand (압력수준과 세립분함유량에 따른 모래의 압축특성)

  • Kim, Uk-Gie;Zhuang, Li;Kim, Ju-Hyun
    • Journal of the Korean Geotechnical Society
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    • v.28 no.9
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    • pp.97-106
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    • 2012
  • In order to investigate mechanics of mixtures composed of sand and non-plastic silt, various specimens, with sand dominating the soil structure, and with varying fines content, fines content varying were produced. Isotropic consolidation tests were performed using high pressure triaxial test apparatus within high pressure levels where sand grain crushing happened. Experimental results showed that compressive curve of sand after yielding contracts to the NCL due to breakage of sand grains. Moreover, with the increase of fines content, coarse grains are surrounded by fines to form cushion effect, which made the breakage of coarse grains become difficult. Therefore, the maximum inclination of compressive curve became flatter and yield stress increased.

Field Tests for the Application of Bottom Ash and Shred Tire as Fill Materials (석탄회 및 폐타이어의 성토재로의 적용성 검토를 위한 현장시험)

  • Lee, Sungjin;Lee, Taeyoon
    • Journal of the Korean GEO-environmental Society
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    • v.14 no.10
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    • pp.29-37
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    • 2013
  • In this study, we constructed the test embankment with four kinds of sections(2 kinds of bottom ash; tire shred-bottom ash mixture, weathered soil) in field and had been monitoring the behaviour of the test embankment and change of ground water quality for 1 year. In the geotechnical aspects, there was no relative difference of deformation in 4 test materials section and we could not see the possibility of the strength-reduction of coal ash materials by freezing inside of the embankment. In addition, no settlement was observed in the test sections because the base soil of the test sections was rigid enough that no consolidation was occurred. In the examination of water quality, all of the heavy metals and negative ions were detected below the drinking water standards except for sulfate($SO_4^{2-}$). In the beginning of measurement, higher concentrations of sulfate from 4 test sections were detected than drinking water standard for 20 days after beginning of the test but the concentrations decreased below the drinking water standard after 50 days after the tests.

Time dependent behavior of piled raft foundation in clayey soil

  • Fattah, Mohammed Y.;Al-Mosawi, Mosa J.;Al-Zayadi, Abbas A.O.
    • Geomechanics and Engineering
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    • v.5 no.1
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    • pp.17-36
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    • 2013
  • Settlement of the piled raft can be estimated even after years of completing the construction of any structure over the foundation. This study is devoted to carry out numerical analysis by the finite element method of the consolidation settlement of piled rafts over clayey soils and detecting the dissipation of excess pore water pressure and its effect on bearing capacity of piled raft foundations. The ABAQUS computer program is used as a finite element tool and the soil is represented by the modified Drucker-Prager/cap model. Five different configurations of pile groups are simulated in the finite element analysis. It was found that the settlement beneath the piled raft foundation resulted from the dissipation of excess pore water pressure considerably affects the final settlement of the foundation, and enough attention should be paid to settlement variation with time. The settlement behavior of unpiled raft shows bowl shaped settlement profile with maximum at the center. The degree of curvature of the raft under vertical load increases with the decrease of the raft thickness. For the same vertical load, the differential settlement of raft of ($10{\times}10m$) size decreases by more than 90% when the raft thickness increased from 0.75 m to 1.5 m. The average load carried by piles depends on the number of piles in the group. The groups of ($2{\times}1$, $3{\times}1$, $2{\times}2$, $3{\times}2$, and $3{\times}3$) piles were found to carry about 24%, 32%, 42%, 58%, and 79% of the total vertical load. The distribution of load between piles becomes more uniform with the increase of raft thickness.