• Title/Summary/Keyword: the earth

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An Analysis on High School Students' Perceptions of Earth Science Scientists (지구과학자에 대한 고등학생들의 인식 분석)

  • Kim, Yun-Ji
    • Journal of the Korean Society of Earth Science Education
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    • v.7 no.2
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    • pp.159-168
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    • 2014
  • This study was designed to 10 questions as development of GAP program for ninety high school students(each student of 30 with achievement as high, medium, and low categories), it was analyzed the perception of Earth scientist. High school students have a positive perception about a course in Earth science, but they have lack of knowledge about Earth scientist as a career man, and they can't recognize Earth scientist as a career. A failure of learning of Earth science for Students with low level achievement leads to a negative perception about Earth scientist and disconnection to future career. School education should provide an opportunity to encounter Earth scientist for students and it is badly in need of effort to connect to the job training program.

Investigation on Recently Developed Reinforced Soil Wall System (국내 보강토옹벽 신기술 조사 연구)

  • Lee, Kwang-Wu;Cho, Sam-Deok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.158-167
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    • 2008
  • Reinforced earth wall system has been popularized since its introduction to Korean civil engineering society in early 1980's. Nowadays, the increased use of reinforced earth wall for the purpose of obtaining more land brings several additional demands such as environmental-friendly, better stable and constructible, and economical system. This paper introduces some recently developed reinforced earth wall systems with consideration of the current demands.

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Effects of the earth fissure on the seismic response characteristics of a nearby metro station

  • Jiang Chang;Yahong Deng;Huandong Mu
    • Earthquakes and Structures
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    • v.24 no.1
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    • pp.53-64
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    • 2023
  • Earth fissures with several kilometers will inevitably approach or cross the metro line, significantly threatening the safety of the underground structure in the earth fissure site. However, the influence of the earth fissure site's amplification effect on the metro station's dynamic response is still unclear. A representative earth fissure in Xi'an was taken as an example to establish a numerical model of a metro station in the earth fissure site. The dynamic response characteristics of the metro stations at different distances from the earth fissure under various seismic waves were calculated. The results show that the existence of the earth fissure significantly amplifies the dynamic response of the nearby underground structures. The responses of the axial force, shear force, bending moment, normal stress, horizontal displacement, inter-story drift, and relative slip of the metro station were all amplified within a specific influence range. The amplification effect increases with the seismic wave intensity. The amplification effect caused by the earth fissure has relatively weak impacts on the axial shear, shear force, bending movement, normal stress, and horizontal movement; slightly larger impacts on the inter-story drift and acceleration; and a significant impact on the relative slip. The influence ranges of the axial force and normal stress are approximately 20 m. The influence ranges of the acceleration and inter-story drift can reach 30 m. Therefore, the seismic fortification level of the underground structure in the earth fissure site needs to be improved.

The Development and Applying Effects of Systems Thinking Teaching Program for Improving Recognition of the Earth Systems in Elementary Science Education (초등과학교육에서 지구시스템 인식강화를 위한 시스템사고 교육 프로그램 개발 및 적용효과)

  • Moon, Byoung-Chan
    • Journal of the Korean Society of Earth Science Education
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    • v.7 no.3
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    • pp.313-326
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    • 2014
  • The purpose of this study is to explore the applying possibility of the Earth Systems Education(ESE) in elementary school science education through the improving of students' recognition with the earth systematic nature by systems thinking education - for this was the recognizing as earth systematic nature was the key element of ESE, and the systems thinking skill is accredited very effective tool for the understanding with earth systematic nature. For this, the systems thinking's teaching-learning programs were developed and applied to the 6th students (21s) for 10hours' classes. The results of this study are as follows; In most of the 6th students didn't recognize with earth systematic nature from a lack of understanding of the vapor being in every nature environments. In systems teaching-learning classes, most of students participated positively in learning activities and achieved the aim of a lesson. In the testing results for students' recognition improving to earth systematic nature after the systems thinking education, about 24% students were showed the improving results of the recognition with earth systematic nature. Consequently, It is suggested that just as the achieving of the points of ESE in elementary school science education, the approaching method of the systems thinking education is worth attempting to applying of the ESE.

A Case Study on the Method of High-rise Wall in Rammed Earth Construction (고층형 흙다짐 공법의 사례 연구)

  • Lee, JongKook;Kim, HoChun;Lee, SangWon
    • KIEAE Journal
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    • v.8 no.3
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    • pp.85-91
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    • 2008
  • We intends to understand the rammed earth method and suggest the possibilities of adoption on high-rise rammed earth structures through the case study on the method. The rammed earth construction has been regarded as one of the solutions in the modern environmental-friendly construction field, thus according to such trend, this study tries to find out the limitations of the rammed earth structures to be multistory and grope for solutions in the attached wall construction method. The procedures of this research is to figure out the limitations of rammed earth structures through theoretical consideration on those structures and analyze the actual cases of them, and to assure the possibilities on the development of the rammed earth method that can make the structures multistory earthen structures in the rammed earth method and induce immediate issues for it.

Analysis on Coring Earth Electrode in Progress of Time (코아링 접지전극의 경년변화 해석)

  • Oh, Seong-Bo;Kim, Se-Ho;Kim, Ho-Chan;Boo, Chang-Jin;Ahan, Jae-Hyun;Ko, Seoung-Min;Ko, Young-Soo
    • Proceedings of the KIEE Conference
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    • 2006.07e
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    • pp.89-90
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    • 2006
  • Recent earth systems not only make earth resistance decreased by installing earth electrode but also are demanded by earth construction for the protection of human life and equipments through total investigation about circumstances. Layer constructions in Jeju island consist of multi-layer of scoria, rocks and shale except clay layers on the surface, which needs the construction of the coring earth electrode suitable in the condition of the area. For this reason, we've used the coring earth electrode. But the coring earth electrode is expected to slow down the performance of this equipment according to the progress of time changing the effects. It is also applied for the stability of earth system construction and management after the construction work analyzing the condition of the earth system. Therefore, this is actually focused on the analysis on measuring the earth resistance and the soil resistivity that cover the range where the remarkable contrast can be expected to be seen in the layer structures.

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Earth pressure on a vertical shaft considering the arching effect in c-𝜙 soil

  • Lee, In-Mo;Kim, Do-Hoon;Kim, Kyoung-Yul;Lee, Seok-Won
    • Geomechanics and Engineering
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    • v.11 no.6
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    • pp.879-896
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    • 2016
  • A new earth pressure equation considering the arching effect in $c-{\phi}$ soils was proposed for the accurate calculation of earth pressure on circular vertical shafts. The arching effect and the subsequent load recovery phenomenon occurring due to multi-step excavation were quantitatively investigated through laboratory tests. The new earth pressure equation was verified by comparing the test results with the earth pressures predicted by new equation in various soil conditions. Resulting from testing by using multi-step excavation, the arching effect and load recovery were clearly observed. The test results in $c-{\phi}$ soil showed that even a small amount of cohesion can cause the earth pressure to decrease significantly. Therefore, predicting earth pressure without considering such cohesion can lead to overestimation of earth pressure. The test results in various ground conditions demonstrated that the newly proposed equation, which enables consideration of cohesion as appropriate, is the most reliable equation for predicting earth pressure in both ${\phi}$ soil and $c-{\phi}$ soil. The comparison of the theoretical equations with the field data measured on a real construction site also highlighted the best-fitness of the theoretical equation in predicting earth pressure.

Development of the ANN for the Estimation of Earth Parameter and Equivalent Resistivity

  • Ji Pyeong-Shik;Lee Jong-Pil;Shin Kwan-Woo;Lim Jae-Yoon;Kim Sung-Soo
    • KIEE International Transactions on Power Engineering
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    • v.5A no.4
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    • pp.350-356
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    • 2005
  • Earth equipments are essential to protect humans and other types of equipment from abnormal conditions. Earth resistance and potential must be restricted within a low value. An estimation algorithm of earth parameters and equivalent resistivity is introduced to calculate reliable earth resistance in this research. The proposed algorithm is based on the relationship between apparent resistances and earth parameters. The proposed algorithm, which approximates the non-linear characteristics of earth by using the Artificial Neural Network (ANN), estimates the earth parameters and equivalent resistivity. The effectiveness of the proposed method is verified with case studies.

Reinforced Earth Structures (보강토 공법)

  • 이은수
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.10a
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    • pp.301-313
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    • 2001
  • Reinforced earth is a composite construction material in which the strength of engineering fill is enhanced by the addition of strong tensile reinforcement in variable types. The basic mechanism of reinforced earth involves the generation of frictional forces and bearing resistances between the soil and the reinforcement. The primitive structure of reinforced earth in Korean peninsula were found as the earth wall built around the old fort In about 3rd century Modern reinforced earth was introduced to Korea early 1980, and spreaded tremendously through the nation. Among them, not a few reinforced earth walls which were built ignored over all stabilities have been collapsed. In this paper basic concepts, economic benefits, design considerations and future applicable trends of reinforced earth are reviewed in simple manners.

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