• 제목/요약/키워드: shape of the earth

검색결과 468건 처리시간 0.031초

이형제체의 침투에 관한 연구 (A Study of Seepage in Earth Structure of Zone Types)

  • 신방웅;이봉직
    • 대한토목학회논문집
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    • 제11권1호
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    • pp.135-144
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    • 1991
  • 본 논문에서는 투수계수가 서로 다른 재료로 축조된 구조물내의 침투현상에 대하여 고찰하였으며, 또한 사면경사가 1:1.5, 1:2.0, 1:2.5인 3가지 경우에 대하여 각 모형별로 수위 및 수위상승속도를 변화시켜 가면서 이에 따른 침윤선의 변화 상태도 함께 고찰하였다. 그리고 이 같은 모형실험결과를 양적차분근사해에 초기조건과 경계조건을 부여하여 구한 수치해와 비교, 분석하였다.

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좌표측정 센서시스템을 이용한 흙막이 변위 계측 (Measurements of Earth Retaining Wall using Coordinate Sensor System)

  • 노태성;임홍철;한병원
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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    • pp.196-197
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    • 2015
  • Measurements of temporary earth retaining wall during construction are essential for the safety and control of building under construction. As there is a rapid development in sensor technologies, new system of coordinate sensor is developed and applied to a construction site. The new system is capable of measuring three dimensional coordinates continuously over time. It makes possible to monitor the behavior of the temporary earth retaining wall real-time. In this paper, the results of such measurements are provided with real data.

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Injection of an Intermediate Fluid into a Rotating Cylindrical Container Filled with Two-layered Fluid

  • Na, Jung-Yul;Hwang, Byong-Jun
    • Journal of the korean society of oceanography
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    • 제31권4호
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    • pp.173-182
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    • 1996
  • A median-density fluid was injected into the upper layer of a two-layered fluid in a rotating cylindrical container. Several sets of the top and bottom boundary configurations were employed and the flow pattern of each layer including the injected fluid was observed to determine the factors that affect the path of the injected intermediate fluid. The axisymmetric path of the intermediate fluid when the upper layer had a free surface, changed into the asymmetric path with bulged-shape radial spreading whenever either the upper layer or the lower layer had ${\beta}$-effect. The internal Fronds number that controls the shape of the interface turned out to be the most important parameter that determines the radial spreading in terms of location and strength. When the upper and lower layer had the ${\beta}$-effect, convective overturning produced anticyclonic vortices at the frontal edge of the intermediate fluid, and that could enhance the vertical mixing of different density fluids. The intermediate fluid did not produce any topographic effect on the upper-layer motion during its spreading over the interface, since its thickness was very small. However, its anticyclonic motion within the bulged-shape produced a cyclonic motion in the lower layer just beneath the bulge.

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환경친화형 그린넷 보강토 옹벽 개발을 위한 식생시험 연구 (A Planting Study on the Development of Eco-friendly Reinforced Earth-Retaining Wall Using Planting Green Net)

  • 정대석
    • 한국환경과학회지
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    • 제16권9호
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    • pp.1099-1102
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    • 2007
  • This paper presents eco-friendly planting method to overcome the problems of existing concrete retaining wall and gabion retaining wall, respectively, based on the examination on existing concrete and gabion retaining wall. Prior to doing this, proper design method was provided through pull out test. Planting method using gabion metal net and L shape green net retaining wall were compared and analyzed. According to this study, it is confirmed that reduction of construction period and economical profit in construction can be achieved by both manufacturing at the factory and self procurement at the job site as well as the use of metal net, which is applied as a substitution of existing strengthening material. For the effect of planting method, the use of L shape green net retaining wall shows superiority to environment-friendly gabion retaining wall in its ability to rootage and germination of the grass. The L shape green net retaining wall had excellent performance in helping rootage of grass and prevention of soil leakage, and even if raining period, remarkable damage of planting mat does not occur when planting mat is applied.

Passive earth pressure for retaining structure considering unsaturation and change of effective unit weight of backfill

  • Zheng, Li;Li, Lin;Li, Jingpei;Sun, De'an
    • Geomechanics and Engineering
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    • 제23권3호
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    • pp.207-215
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    • 2020
  • This paper presents a kinematic limit analysis for passive earth pressure of rigid retaining structures considering the unsaturation of the backfill. Particular emphasis in the current work is focused on the effects of the spatial change in the degree of saturation on the passive earth pressure under different steady-infiltration/evaporation conditions. The incorporation of change of effective unit weight with degree of saturation is the main contribution of this study. The problem is formulated based on the log-spiral failure model rather than the linear wedge failure model, in which both the spatial variations of suction and soil effective unit weight are taken into account. Parametric studies, which cover a wide range of flow conditions, soil types and properties, wall batter, back slope angle as well as the interface friction angle, are performed to investigate the effects of these factors on the passive pressure and the corresponding shape of potential failure surfaces in the backfill. The results reveal that the flow conditions have significant effects on the suction and unit weight of the clayey backfill, and hence greatly impact the passive earth pressure of retaining structures. It is expected that present study could provide an insight into evaluation of the passive earth pressure of retaining structures with unsaturated backfills.

증산의 풍수관(風水觀) 고찰 - 『전경(典經)』을 중심으로 - (A Study on Jeungsan's view of Pungsu: Chiefly focused on Jeonkyung)

  • 박상만
    • 대순사상논총
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    • 제25_2집
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    • pp.45-70
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    • 2015
  • Master Jeungsan understood a general view of Pungsu but actually he used the theory of Pungsu in his own religious perspective, transcending it. The theory of Pungsu is different. But the fact that it is premised on the principle of 'in and yang', the five-element principle, the Book of Changes, energy thought, and To chugi piyung, etc. is generally recognized. The three important elements of Pungsu are mountain, water, and direction or man. Pungsu has formal principles such as Gallyongbeop, Jangpungbeop, Deuksubeop, Jeonghyeolbeop, Jwahyangbeop, and Hyeongukron. etc. In the late of Joseon, Jeungsan established a new traditional thought, understanding Bibopungsu, Gukdopungsu, Minganpungsu, etc. However, he reinterpreted them to be suitable to his religious ideal and let his followers understand them as well. In particular, Jeungsan overcame the previous view on earth and expressed a new perspective to enhance earth up to the level of heaven. In the perspective of the traditional world, earth is lower than heaven, but Jeungsan made it a status equal to heaven. He mentioned that in the past, the culture and history of man was influenced by earth's energy but today, at the age of man respect, he put passive man influenced by earth-condition on the more subjective and active status. Even though he mentioned different Pungsu, Hyeongguk, and Hyeolmyeong, he expressed the shape of Pungsu within the construction of three worlds, the one of heaven and earth transcending good or ill luck or a favorable change in fortune. He practised the expedient of Pungsu from the stand of the construction of heaven and earth instead of the usage of Bibopungsu, Gukdopungsu, and Minganpungsu. He diagnosed that the division of the world is caused by the one of earth and tried to solve it. Moreover, he said that Myeongdang(a propitious site) must be the man-orientation rather than the earth-orientation. It means that Pungsu, stressing the energy of earth and turning one's luck, is changing into the world of man-orientation. In other words, Jeungsan diagnosed the world of Pungsu but he ultimately used Pungsu theory in building up his own view of religious world transcending such a theory.

교대변위 및 도로침하에 대한 사례분석 (Case Analysis of Abutment Displacement and Pavement settlement)

  • 박찬호;김수일
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 1994년도 봄 학술발표회 논문집
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    • pp.19-30
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    • 1994
  • This paper reports a case study of aboutment displacement and pavement settlement observed at the construction site for highway bridges. The emphasis was on quantifying the horizontal deflections of about and pavement settlement on the backfill surface. It is shown that in soft clay, bridge aboutments on pile foundations are subjected to lateral earth pressures due to lateral soil movement. Based on the results analyzed, the earth pressure was predicted by deflection shape of piles based on the results of a numerical analysis and an analytical study. Also, the long term settlement of soil below pavement was estimated.

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천해 연안역에서의 수중소음의 특징 (Characteristics of Ambient-Noise in the Shallow Coastal Area)

  • 나정열;최진혁;김재완
    • 한국음향학회지
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    • 제10권6호
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    • pp.58-63
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    • 1991
  • 선박소음이 우세한 해역에서 측정된 수중소음의 크기를 분석한 결과 100Hz 미만에서는 깊은 수 심에서의 소음 크기가 낮은 수심에서보다 크게 나타나고 있다. 한편 계절적인 소음 크기의 변화는 dam 파 전달 조건에 좌우되며, 일반적인 spectrum shape은 Urick의 선박소음이 우세한 경우의 spectrum과 매우 유사하다.

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순간 및 연속 추력을 이용한 지구-달 최적 전이궤도 설계에 관한 연구 (A Study on Optimal Earth-Moon Transfer Orbit Design Using Mixed Impulsive and Continuous Thrust)

  • 노태수;전경언
    • 한국항공우주학회지
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    • 제38권7호
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    • pp.684-692
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    • 2010
  • 본 논문에서는 지구-달 천이를 위한 최적 궤도 설계에 관한 연구를 수행하였다. 지구와 달의 인력을 동시에 고려한 평면상 제한 3체 궤도 운동 모델을 바탕으로 지구 출발시에는 순간 추력을, 지구-달 천이 과정 및 달 임무궤도 투입시에는 연속 추력을 사용하는 혼합형 궤도전이 방법을 제시하였다. 최적화 풀이 방법으로서 Direct Transcription 및 Collocation을 이용한 비선형 프로그래밍 기법을 적용하였으며, 지구 출발 및 달 임무궤도 투입 궤적의 형상은 순간 추력의 연속 추력에 대한 상대 가중치 및 비행시간에 의하여 매우 달라질 수 있음을 파악하였다.

행성 궤도의 모양에 관한 중학교 영재 학생들의 증거 기반 추론 (Middle School Gifted Students' Evidence-Based Reasoning about the Shape of a Planet's Orbit)

  • 오필석
    • 한국지구과학회지
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    • 제42권1호
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    • pp.118-131
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    • 2021
  • 본 연구의 목적은 중학교 영재 학생들이 수행한 증거 기반 추론의 특징을 조사하는 것이었다. 연구를 위한 자료는 수도권에 위치한 한 대학교의 영재 교육원에서 중학교 영재 학생들이 비대면 방식으로 진행한 탐구 과제를 통해 수집되었다. 학생들에게 수성의 최대 이각을 관측한 자료를 제공하고 이 자료를 이용하여 수성의 공전 궤도를 작도하게 하였다. 또, 작도 전에 수성의 궤도에 대한 자신의 가설을 진술하게 하였으며 작도 결과를 증거로 삼아 수성 궤도의 모양을 추론하게 하였다. 학생들이 제출한 보고서의 내용을 분석하여 수성의 공전 궤도 모양에 관한 판단 유형을 5가지로 분류하고 가설 및 증거에 관한 추론 유형을 4가지로 분류한 후, 판단 유형에 따른 증거 기반 추론의 특징을 정리하였다. 분석 결과를 토대로, 증거 기반 추론에서는 증거에 대한 적절한 해석이 중요하고, 이론과 증거의 조화가 핵심적인 역할을 하며, 복수의 가설을 상정하는 것이 유리할 수 있음을 논의하였고, 지구과학 교육을 위한 시사점을 제안하였다.