• Title/Summary/Keyword: 수평형

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A Strategic Policy for the Beach Reservation utilizing Steel Type Breakwater (철재형 이안제를 활용한 전략적 해안 보전 정책)

  • Gwon, Hyeok-Min;Lee, Jeong-Ryeol;Yun, Gang-Hun
    • Water for future
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    • v.47 no.2
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    • pp.87-97
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    • 2014
  • 해안의 침식저감은 해안보전 정책 중에서 가장 중요한 목표가 되고 있다. 하지만, 침식을 야기하는 요인의 다양성과 결과예측의 어려움 등으로 인하여 기존공법의 유효성에 많은 의문이 있다. 이러한 대응효과의 불확실성을 극복하는 하나의 방법으로서 해안모래의 사정에 따라 그때그때 조치하는 유연한 대응을 생각할 수 있는데 이러한 관리형 대응을 실현하기 위해서는 만족할 만한 핵심요소 기술이 필요하다. 최근 들어 구조형식이 간단하면서 경제적인 투과성 철재형 이안제가 개발되었다. 본 해안침식저감용 기술은 파랑제어가 수평판으로 가능하고 착탈식이며 이동이 간단하다. 이러한 특징을 활용하면 해안의 사정에 따라 관리할 수 있는 전략적 해안보전이 가능해 질 수 있다. 특히 본 구조물은 평균해수면 상승에 대해서도 추가비용이 거의 발생하지 않으므로 범용적 활용을 기대할 수 있어서 빠른 기술축척을 기대할 수 있다. 본 연구는 전략적 해안 보전 정책을 수행하기 위한 핵심요소기술의 적용성에 대하여 고찰하였다. 연구결과, 해안의 침 퇴적 사정에 따라 그때그때 파에너지의 투과율을 가변화시킴으로서 해안보호를 경제적으로 할 수 있음을 확인하였다.

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Analysis of Laterally Loaded Pile-Bent Structure with Varying Cross-sectional Area (변단면 파일벤트 구조의 수평거동 분석)

  • Jeong, Sang-Seom;Sung, Chul-Gyu;Ko, Jun-Young;Kim, Soo-Il
    • Journal of the Korean Geotechnical Society
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    • v.25 no.4
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    • pp.69-75
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    • 2009
  • The load distribution and deformation of pile-bent structures are investigated using a numerical study. A numerical analysis that takes into account the effects of varying cross-sectional area was performed for different pier diameters, loading steps, and soil conditions. Through the comparison study, it is shown that the location of maximum bending moment is almost the same per each loading step, regardless of varying cross-sections. However, the member force (i.e., stress of pile material) has the largest value at the ground surface when the cross-section is changed. Based on the results obtained, it is found that the location of maximum member force influences highly the behavior of pile-bent structure with varying cross-sections for repair works.

Evaluation of Lateral Load Capacity of Drilled Shafts with Pile Shape and Soil Conditions (말뚝형태 및 지반조건에 따른 현장타설말뚝의 수평지지력 평가)

  • Lee, Jun-Hwan;Paik, Kyu-Ho;Kim, Dae-Hong;Hwang, Sung-Wuk;Kim, Min-Kee
    • Journal of the Korean Geotechnical Society
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    • v.23 no.2
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    • pp.61-69
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    • 2007
  • In this study, experimental analysis was performed about lateral load capacity and behavior of laterally loaded-bored piles for soil conditions and pile shape, i.e. cylindrical and taper piles. Also, Calibration chamber load tests were performed for cylindrical and taper piles considering the variations of relative densities and restraint stresses. According to the results of chamber tests, it was found that, while both vertical and horizontal stresses affect load-responses and ultimate lateral load capacity of laterally loaded piles, effect of the horizontal stress was larger than that of the vertical stress. Effect of lateral load capacity and behavior was relatively small compared to relative density and stress state of soils surrounding piles, but showed a little difference for soil conditions. From comparison between predicted and measured lateral load capacity, it was observed that predicted results differ significantly from measured results. This is mainly due to the fact that the effect of horizontal stress is not considered in the conventional prediction methods.

The Behavior and Resistance of Connected-pile Foundations for Transmission Tower from In-situ Lateral Load Tests (송전용 철탑기초의 현장수평재하시험을 통한 연결형 말뚝기초의 거동 및 지지력특성)

  • Kyung, Doo-Hyun;Lee, Jun-Hwan;Paik, Kyu-Ho;Kim, Dae-Hong;Kim, Dae-Hak
    • Journal of the Korean Geotechnical Society
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    • v.28 no.2
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    • pp.57-70
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    • 2012
  • For soft ground, a pile foundation is typically used as a substructure of transmission tower. However, differential settlement between the foundations can cause structural damage of transmission tower. The connected-pile foundation is a type of group foundation consisting of four foundations connected with beams, and it was suggested in USA and Japan. In this study, a series of 1/8 scale model pile tests were performed to investigate the effect of load direction and stiffness of connecting beam on the responses of connected-pile foundation. As a result, the load capacities of the connected-pile foundation were larger than those of the conventional group pile foundation. For example, under the given test conditions in this paper, the resistibility against differential settlement was improved significantly for connected-pile foundation and its efficiency was maximized when the stiffness of connecting beams is about 25% of the mat foundation.

Numerical Analysis of Horizontal Collector Well in Riverbank Filtration (수평 방사형 집수정 활용 강변여과 취수 수치 분석)

  • Kim, Hyoung-Soo;Jeong, Jae-Hoon
    • Journal of Soil and Groundwater Environment
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    • v.14 no.1
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    • pp.1-10
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    • 2009
  • Groundwater flow due to intake of horizontal collector well in riverbank filtration site was analyzed by use of numerical groundwater modeling program (FEFLOW 5.1). Drawdowns of groundwater table nearby collector well were evaluated according to variations of several conditions; pumping rate, thickness of aquifer, offset distance from well to shore line of stream, conductance of streambed. It is observed that the drawdowns of groundwater table are clearly changed according to the variations of these conditions. The results of sensitive analysis shows that the thickness of alluvial aquifer and the offset distance are more sensitive than the conductance of streambed in evaluation of drawdown. This result implies that hydrogeological conditions, as like thickness of aquifer and its distribution in the site are important factors in site selection and evaluating the availability of riverbank filtration intake using horizontal collector well system. It is also revealed that numerical modeling using FEFLOW with 1-D discrete element feature can give efficient quantitative evaluation of horizontal collector well and estimation of availability of riverbank filtration site.

Estimation of Appropriate Reinforcement Length of Casing for the Pile of Pile Bent System through Numerical Analysis (수치해석을 통한 단일형 현장타설말뚝 외부강관의 적정 보강길이 산정)

  • Yang, Wooyeol;Kim, Wanho;Lee, Kangil
    • Journal of the Korean GEO-environmental Society
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    • v.22 no.6
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    • pp.5-15
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    • 2021
  • One of the construction methods applied as a pier foundation type is a single type cast-in-place pile. In applying a pile bent system as a foundation type, the main concern in designing can be said to secure the lateral bearing capacity of pile structure in system. In addition, to increase the rigidity of the pile structure, a method of increasing the lateral bearing capacity by reinforcing the pile structure with a casing has been used. However, although the reinforcing effect and appropriate reinforcing length of casing may vary depending on the soil conditions, there is insufficient studies on this, and for this reason, the entire pile structure in a pile bent system is reinforced with a casing, in the field. In addition, if the length of the entire pile is reinforced with a casing, it may lead to delays in construction and increase in construction costs. That is, in order to more effectively reinforce the pile structure with a casing, it is necessary to study the lateral bearing characteristics of the reinforced pile structure in system. And it should be determined the appropriate reinforcing length of the casing from the evaluated bearing characteristics. Therefore, in this study, the lateral bearing characteristics of piles applied with the reinforcing length of casing for each condition were evaluated through a numerical analysis. And, based on the analysis results, the appropriate reinforcing length of casing was proposed. As a result of the study, it was found that in order to effectively increase the lateral bearing capacity of pile structure, the reinforcing length of casing should be applied twice the influence range of the bending behavior of the pile, 1/β.

Horizontal Bearing Behavior of Group Suction Piles by Numerical Analysis (수치해석을 이용한 그룹형 석션파일의 수평방향 지지거동 분석)

  • Lee, Ju-Hyung;Lee, Si-Hoon;Kim, Sung-Ryul
    • Journal of the Korean Geotechnical Society
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    • v.29 no.11
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    • pp.119-127
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    • 2013
  • Recently, several researches on the development of new economical foundation types have been performed to support floating structures as many offshore structures have been constructed. This study focused on the evaluation of bearing capacity of group suction piles, which are connected by a concrete pile cap. The offshore floating structures are mainly subjected to horizontal loading, so the horizontal bearing capacities of the group suction piles were analyzed by performing 3-dimensional finite element analyses. The group suction piles are expected to behave as a rigid pile due to its shallow embedded depth. Therefore, the detailed soil modeling was necessary to simulate the bearing behavior of soils under low confining pressure. The modulus and the strength of soils were modelled to increase with effective confining pressure in soils. For the parametric study, the center-to-center spacing between piles was varied and two soil types of clay and sands were applied. The analyses results showed that the yielding load of the group pile increased with the increase of the pile spacing and the yielding load of the group piles with 5D spacing was about 3 times larger than that of the single pile with free rotation.

Development of Vertical Type Flammable Gas Generator for Food Waste (수직형 음식물류폐기물 가연성 가스 발생장치 개발)

  • Han, Doo-Hee
    • Proceedings of the KAIS Fall Conference
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    • 2009.12a
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    • pp.93-96
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    • 2009
  • 논문에서는 음식물류폐기물을 건조 및 탄화시켜 감량화하는 과정에 필요한 수직형 음식물류폐기물 가연성 가스발생장치에 관한 것을 보고하였다. 수직형은 열효율이 좋고 수평공간을 작게 차지하여 토지의 효용을 높이고 구조가 상대적으로 단순하여 제작비를 줄일 수 있다.

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Wave Absorbing Characteristics of a Horizontal Submerged Punching Plate (수평형 타공판의 소파특성)

  • 조일형
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.4
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    • pp.265-273
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    • 2002
  • In this paper, wave absorbing characteristics of a horizontal submerged punching plate are investigated throughout the calculation and the experiment. The punching plate with the array of circular holes can force the flow to separate and to form eddies of high vorticity and cause significant energy loss. As an analytic tool, the linear water wave theory and the eigenfunction expansion method is applied. Darcy's law that the normal velocity of the fluid passing through the punching plate is linearly proportional to the pressure difference between two sides of the punching plate is assumed. The proportional constant called the porous coefficient is deeply dependent to the porosity. To obtain the relationship between the porosity and the porous coefficient the systematic model test for the punching plates with 6 different porosities is conducted at 2-dimensional wave tank. It is found that the porous coefficient is linearly proportional to the porosity(b=57.63P-0.9717). It is also noted that the optimal porosity value is near P=0.1 and the optimal range of submergence depth is $d/h\\leq0.2$ within entire frequency range.

Interaction of Flexure-Torsional by eccentric load in horizontal curved 'I' shape girder (편심하중이 작용하는 수평 곡선 I 형 거더의 휨·비틀림 상호작용)

  • Lim, Jeong-Hyeon;Lee, Kee-Sei;Kim, Hee-Soo;Choi, Jun-Ho;Kang, Young-Joung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.9
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    • pp.6385-6390
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    • 2015
  • With bending moment, torsional moment due to geometric properties as "Initial curvature" acts in horizontally curved I-girder. These behavior causes the secondary effect of bending in minor-axis because of interaction between bending and torsion. The bending and torsion interaction cause a loss of load bearing capacity by induced the early inelastic or plasticity condition in curved girder. Also eccentric load by movements of traffic can increase torsion. However, Equation of interaction between bending and torsion for straight girder, not deal with characteristics of curved girder behavior in previous studies, can be overestimated for ultimate strength in horizontally curved I-girder acting vertical force. Therefore, using more rational, obvious suggestion is required when design curved girder. In this study, we identified the bending-torsional moment interaction for the horizontally curved I-girder of the eccentric load acting by FEM analysis.