• 한국산업융합학회 논문집
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• 제5권3호
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• pp.247-254
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• 2002

This study has researched the following conclusion to compare to the existing theory and to examine lateral earth pressure, which have measured to add incremental load on sandy soil, and were different in types of compaction by modeling earth pressure test. Lateral earth pressure by incremental load shows that it is increasing at depth forty four centimeters as 2/3H point for wall high, and under 2/3 H point the variation of earth pressure on incremental load is not conspicuous. Therefor, the more a position of surcharge load is close with fixed wall, the more a variation of lateral earth pressure marks considerably. According to relative compaction density of soil, lateral earth pressure turns up larger effective value for layer compaction test to a thickness of thirty three centimeters than layer compaction test to a thickness of twenty centimeters by the roller.

• 한국안전학회지
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• 제31권4호
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• pp.104-110
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• 2016

The effect of a partially earth anchored cable system on the structural safety of a long span cable-stayed bridge under seismic and wind loads are examined during construction process. By assuming the FCM (free cantilever method) construction stages with structural vulnerability, a multi-mode spectral analysis and a multi-mode buffeting analysis are performed for specific seismic load and wind load, respectively. Results show that the wind load dominates the structural safety of a cable-stayed bridge during construction. And, the application of a partially earth anchored cable system can enhance structural safety under wind load since the maximum pylon moment in the model with partially earth anchored cable system is reduced by 49% under wind load. In contrast, the maximum pylon moment occurred by seismic load is only decreased by 8%.

• Structural Engineering and Mechanics
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• 제48권3호
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• pp.367-382
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• 2013

Different types of long slender pile shall buckle with weak soil and liquefied stratum surrounded. Different from considering single side earth pressure, it was suggested that the lateral earth pressure can be divided into two categories while buckling: the earth pressure that prevent and promotes the lateral movement. Active and passive earth pressure calculation model was proposed supposing earth pressure changed linearly with displacement considering overlying load, shaft resistance, earth pressure at both sides of the pile. Critical buckling load calculation method was proposed based on the principle of minimum potential energy quoting the earth pressure calculation model. The calculation result was contrasted with the field test result of small diameter TC pile (Plastic Tube Cast-in-place pile). The fix form could be fixed-hinged in the actual calculation assuring the accuracy and certain safety factor. The contributions of pile fix form depend on the pile length for the same geological conditions. There exists critical friction value in specific geological conditions that the side friction has larger impact on the critical buckling load while it is less than the value and has less impact with larger value. The buckling load was not simply changed linearly with friction. The buckling load decreases with increased limit active displacement and the load tend to be constant with larger active displacement value; the critical buckling load will be the same for different fix form for the small values.

• 한국안전학회지
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• 제31권4호
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• pp.97-103
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• 2016

This study investigates effects of partially earth anchored cable system on the structural safety for a long-span cable-stayed bridge under dynamic loads such as seismic and wind load. For a three span cable-stayed bridge with a main span length of 810 m, two models are analyzed and compared; one is a bridge model with a self anchored cable system, the other is a bridge model with a partially earth anchored cable system. By performing multi-mode spectrum analysis for a prescribed seismic load and multi-mode buffeting analysis for a fluctuating wind component, the structural response of two models are compared. From results, the partially earth anchored cable system reduce the maximum pylon moment by 66% since earth anchored cables affect the natural frequencies of girder vertical modes and pylon longitudinal modes. In addition, the girder axial forces are decreased, specially the decrement of the axial force is large in seismic load, while girder moment is slightly increased. Thus, the partially earth anchored cable system is effective system not only on reduction of girder axial forces but also improvement of structural safety of a cable-stayed bridge under dynamic loads such as seismic and wind loads.

• 토지주택연구
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• 제7권4호
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• pp.271-279
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• 2016

Recently developed trenchless construction methods ensure stability for the ground settlement by inserting steel pipes along the underpass section and integrating steel pipes before ground excavation to form pipe-roof. This study is to confirm the reinforcing effect of pipe-roof by measuring lateral earth pressure acting on the underpass constructed by the STS (Steel Tube Slab) construction method. For this purpose, lateral earth pressure was measured at the left and right side of the pipe-roof after installing earth pressure cells. As a result, lateral earth pressure was measured with considerable reduction because the integrated pipe-roof shared surcharge. Therefore, economic design for the underpass could be expected by sharing design load by pipe-roof. In addition, construction cost was analyzed according to the design-load sharing ratio by pipe-roof. As pipe-roof shares design load by 40%, the total construction cost can decrease by almost 10% in the case of four-lane underpass.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.166-171
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• 2008

We cannot imagine any more the environment and energy problems are separated from our lives. The various attempts to solve these problems are made all over the world. In this study it was performed to analyze a different heating and cooling load depending on the earth-sheltering method and kind of soils by using TRNSYS 16 as the first step to establish the design guidelines for earth-sheltered architecture, one of the eco-friendly and low energy consuming building types. After performing this simulation, we found the result like this. It is the most lowest load in case of all of walls and roof being earth-sheltered. But considering of the load reduction rate, the effect of earth-sheltering the exterior vertical wall is more efficient for load reduction than the one of earth-sheltering a roof. And we got a lower thermal load in case of a lower heat conductivity of soil. Afterwards we will conduct a further study for boundary condition at earth-sheltered surface and the simulation analysis about the sensitivity variables. The final goal of this study is preparing the design guidelines for earth-sheltered architecture. so we will contribute to building energy saving.

• 한국지반공학회논문집
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• 제26권12호
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• pp.51-60
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• 2010

자중에 의한 토압은 일반적으로 깊이에 따라 선형비례하여 증가되지만, 상재하중에 의해 발생되는 토압은 분포형태와 지반상태 및 경계조건에 따라 다르게 분포한다. 본 연구에서는 변위가 구속된 강성벽체에 연직상재하중에 의한 토압분포를 실험적으로 연구하기 위하여 실내모형토조[30 cm(폭) ${\times}$ 110 cm(길이) ${\times}$ 88 cm(높이)]에 각 2개의 로드셀이 배치된 8개의 토압판으로 구성된 강성벽체를 설치하여 연직상재하중의 크기와 위치(벽체에서 이격거리)를 변화시켜 가면서 토압분포와 토압의 영향범위를 관찰하였다. 실험결과, 연직상재하중에 의해 발생되는 수평토압은 일정위치에서 최대값을 보이고 깊어질수록 감소하여 한계깊이를 초과하면 무시할 만큼 작아졌다. 수평토압이 최대가 되는 깊이와 한계깊이는 연직상재하중의 크기와는 무관하게 벽체와의 이격거리에 따라 다르게 나타났다.

• 한국항공우주학회지
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• 제45권10호
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• pp.898-906
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• 2017

본 논문은 우주선의 우주궤도 상에서 받는 외부 열원을 효과적이고 정확하게 계산할 수 있는 방법에 대해 논한다. 우주 외부 열원은 크게 태양직사광, 지구반사광, 지구복사열 세가지로 구분할 수 있다. 본 논문은 지구반사광과 지구복사열이 확산반사 및 방사를 따른다고 가정하고 지구표면을 다수의 구역들로 분할하여 이들과 인공위성 표면과의 반사/복사열을 계산하여 합산하였다. 본 연구에는 이들의 엄밀 적분식을 적용하여 수렴성을 극대화하였으며 많은 경우 정확한 결과를 가져올 수 있음을 알 수 있다. 그리고 외부 열원과 위성 표면 사이의 광선 차폐를 판단하기 위해 KD Tree Ray Tracing을 적용한 인공위성 궤도 열하중 계산 알고리즘을 개발하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.807-812
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• 2008

The various attempts is made to solve the energy and environment problems. In addition, people interested in their life quality want the more eco-friendly living space. So we suggested that the earth-sheltered house could be one of the eco-friendly and low energy consuming houses to meet the social interest. And we also made data for design of the earth-sheltered house to be applicable to climate of Korea. In this study, a simulation was performed to estimate a boundary temperature according to earth sheltering thickness at the earth-sheltered part(exterior wall) in the case of earth sheltering on the plane ground not using a sloped site. And we analyzed the reduction of a thermal load by using this boundary temperature. We also compared a case of earth sheltering at the vertical wall with a case of earth sheltering at the roof to know the thermal reduction effect of a case of earth sheltering at the vertical wall.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.149-156
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• 2002

Field measurements were carried out in this study to investigate the behavior of cut and cover tunnel such as the distribution and the magnitude of the earth pressure during back fill process of the ground material. Three kinds of measuring instruments, such as the earth pressure load cell, the concrete strain gauge and the reinforcing bar meter of embedded type in concrete structure were installed and measured. Earth pressure load cells, installed after construction of the tunnel lining, measure the outside forces acting on the tunnel lining with radial directions. Three load cells were installed at the crown, the right and the left shoulder of the tunnel, respectively. Three sets of reinforcing bar meter were installed in the double reinforcements of the tunnel lining and their locations were the same with the position of the earth pressure load cells. Concrete strain gauge was installed only one site of the upper compressive part at the tunnel crown. Based on the measuring results in the field, the deformation and the earth pressure acting on the tunnel lining were investigated with the back fill process of the ground material. Considerations on the validity of the measuring results were paid. For the analysis of measurements, after dividing back fill process into three steps, various factors which affect on the behavior of tunnel lining were investigated at each step.