• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.517-520
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• 2005

The embedded suction anchor(ESA) is and anchor that is driven by a suction pile. The cross-sectional shape of the ESA anchor is circle. Its diameter is the same as that of the suction pile that is used to drive it into the seafloor. For the installation, the anchor is attached to the tip of the suction pile and then driven as a unit with the pile by and applied suction pressure. Once the ESA anchor reaches the desired depth, the pile is retrieved by applying a positive pressure. Finally, only the ESA anchor remains in the soil layer. This paper presents the results of centrifuge model tests to investigate ESA pullout capacity. The main parameters that have effects on the pullout capacity of ESA may include g-level, embedded depth, direction of loading, and loading point. The results of tests show that the pullout loading capacities increase as the loading point shift toward the tip of the anchors for a given loading direction. They also indicate that the loading point associated with the maximum pullout loading capacity is located at approximately 67 percent of the anchor length from the top for the horizontal load.

• 한국해양공학회지
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• 제27권1호
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• pp.59-66
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• 2013

A suction anchor is one of the most popular anchors for deepsea floating systems. An anchor used for catenary mooring is predominantly under a horizontal load. In this study, the behavior of a suction anchor installed in cohesionless soil was investigated when the anchor was mainly subjected to a horizontal load induced by a catenary line. In order to study the behavior of the suction anchor, 3D FEM analysis models were developed and analyzed. Depending on the location of the load (padeye), the ultimate horizontal load was monitored. The distributions of the reaction forces around the anchor induced by the seabed were analyzed using the circumferential stress to understand the behavior of the suction anchor under a horizontal load.

• 한국산학기술학회논문지
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• 제21권10호
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• pp.267-273
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• 2020

석션 앵커는 비교적 간편한 설치 방식과 높은 안정성으로 인해 부유식 구조물을 고정하기 위한 기초로 사용된다. 최근, 허용 변위가 작은 부유식 구조물이 증가함에 따라, 석션 앵커의 유발 변위 평가에 대한 수요가 높아졌다. 하지만, 기존 석션 앵커의 연구는 앵커 지지력 평가에 초점을 두었으며, 앵커의 변위에 관한 연구는 중점적으로 수행되지 않았다. 특히, 경사진 하중을 받는 석션 앵커의 주된 변위인, 회전 거동을 평가한 연구는 매우 부족한 실정이다. 따라서 본 논문에서는 경사 인발 하중이 작용하는 석션 앵커의 회전 거동을 모형실험을 통해 비교 및 분석 하였다. 모형실험은 센트리퓨지 실험 장비를 사용하였으며, 실험 변수로는 하중의 경사도, 앵커의 크기 및 종횡비가 고려되었다. 하중-회전 변위 곡선을 산정하여, 실험 변수에 따른 석션 앵커의 회전량을 비교하였다. 실험 결과, 석션 앵커의 회전 거동은 하중의 경사도에 큰 영향을 받았으며, 앵커의 크기 및 종횡비에 따른 회전량의 차이는 크지 않았다.

• 한국지반공학회논문집
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• 제30권11호
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• pp.61-69
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• 2014

본 연구에서는 수치해석을 이용하여 모래지반에 설치된 병렬식 그룹석션앵커의 인발하중에 대한 거동을 분석하였다. 단일형과 병렬식 그룹석션 앵커에 대한 수치 모델을 구성하고 인발하중을 재하하여 하중재하점의 위치, 길이/직경비, 하중경사 및 단위앵커간 간격에 따른 그룹형 석션앵커의 인발지지력에 대한 영향을 연구하였다. 더블형과 트리플 그룹앵커의 인발지지력은 단일앵커의 인발지지력 대비 1.7배와 2.4배로 나타났고, 설치간격이 증가함에 따라 그 증가율은 증가하였다. 하중재하점, 하중경사, 단위앵커의 형상비의 차이는 그룹앵커의 인발저항력 증가비에 큰 영향을 주지 않는 것으로 나타났다.

• Ocean Systems Engineering
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• 제5권4호
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• pp.279-299
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• 2015

Suction anchors are widely adopted and play an important role in mooring systems. However, how to reliably predict the failure mode and ultimate pullout capacity of the anchor in sand, especially by an easy-to-use theoretical method, is still a great challenge. Existing methods for predicting the inclined pullout capacity of suction anchors in sand are mainly based on experiments or finite element analysis. In the present work, based on a rational mechanical model for suction anchors and the failure mechanism of the anchor in the seabed, an analytical model is developed which can predict the failure mode and ultimate pullout capacity of suction anchors in sand under inclined loading. Detailed parametric analysis is performed to explore the effects of different parameters on the failure mode and ultimate pullout capacity of the anchor. To examine the present model, the results from experiments and finite element analysis are employed to compare with the theoretical predictions, and a general agreement is obtained. An analytical method that can evaluate the optimal position of the attachment point is also proposed in the present study. The present work demonstrates that the failure mode and pullout capacity of suction anchors in sand can be easily and reasonably predicted by the theoretical model, which might be a useful supplement to the experimental and numerical methods in analyzing the behavior of suction anchors.

• Ocean Systems Engineering
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• 제3권2호
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• pp.79-95
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• 2013

Suction anchors are widely adopted in mooring systems. However there are still challenges in predicting the failure mode and ultimate pullout capacity of the anchor. Previously published methods for predicting the inclined pullout capacity of suction anchors are mainly based on experimental data or the FEM analysis. In the present work, an analytical method that is capable of predicting the failure mode and ultimate pullout capacity of the suction anchor in clay under inclined loading is developed. This method is based on a rational mechanical model for suction anchors and the knowledge of the mechanism that the anchor fails in seabed soils. In order to examine the analytical model, the failure angle and pullout capacity of suction anchors from FEM simulation, numerical solution and laboratory tests in uniform and linear cohesive soils are employed to compare with the theoretical predictions and the agreement is satisfactory. An analytical method that can evaluate the optimal position of the attachment point is also proposed in the present study. The present work proves that the failure mode and pullout capacity of suction anchors can be reasonably determined by the developed analytical method.

• 대한토목학회논문집
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• 제34권1호
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• pp.167-173
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• 2014

석션 매입 앵커(Embedded Suction Anchor; ESA)는 석션 기초(Suction Pile or Caisson)을 이용하여 앵커를 지중에 매설한 후 인발에 저항하는 계류앵커형식이다. 본 연구에서는 ALE (Arbitrary Larangan Eulerian) Adpative Meshing 기법을 이용한 수치해석을 통해 석션 매입 앵커의 인발 거동을 모사하고, 그 결과를 기존 연구에서 수행된 원심모형 실험 및 한계 평형법을 이용한 해석적 방법의 결과와 비교 분석 하였다. 이를 통해 앵커의 수평 연직 경사 방향의 인발 거동을 평가하였으며, 수치 해석 결과, 수평 재하 시 중간 위치에서 가장 큰 저항력을 발휘하는 것으로 나타났다. 연직 재하의 경우 재하 위치와 무관하게 유사한 저항력이 발휘 되었으며, 수평 저항력이 가장 큰 중간 위치에서 경사 하중을 가한 결과 경사각이 증가할수록 인발 저항력이 감소하는 것으로 나타났다.

• 한국안전학회지
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• 제12권4호
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• pp.108-113
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• 1997

Plate anchors are primarily used in the foundation construction of earth-supported and earth-retaining structures. In order to estimate uplift capacity as well as suction force of clay, model tests were peformed with respect to various embedment depths and two different moisture contents in the prepared saturated kaolinite. Further, suction effects on the ultimate uplift capacity, at the various embedment depths of anchor, were also taken into account. Test results show that ultimate uplift capacity including suction force increases from 4.2kg at H/D=1 upto 11.6kg at H/D=5 in K1 and from 2.3kg at H/D=1 upto 7.3kg at H/D=5 in K2 respectively. The ratio of $F_s/Q_n/$ decreases along with the increases in the embedment ratio. In general, mud suction force under the ultimate uplift capacity in kaolinite decreases or becomes constant along with the increase of the embedment ratio.

• 한국해양공학회지
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• 제22권6호
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• pp.1-6
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• 2008

Anchors have been commonly used to as foundation systems of the structures that require the uplift resistance. Recently anchors have been used in ocean sediment for mooring systems to stabilizeoffshore structures. In the saturated clayey soil however suction developed between the soil and andchor and affects the uplift capacity of anchor. To estimate the uplift capacity of the andchor accurately, the failure mechanisms of the andchor by the uplift force should also be correctly assumed. The uplift capacity is usually expressed in terms of breakout factors with respect to embedment ratio. In this paper, a two-dimensional plane strain numerical investigation into the vertical uplift capacity of a plate andchor in a clayey soil is described. The breakout factor against their corresponding values of embedment ratio was calculated and plotted along a single curve. The modes of failure mechanism at shallow and deep andchors are also presented.

• 한국해안·해양공학회논문집
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• 제27권3호
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• pp.182-189
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• 2015

ESA는 석션파일에 의해 설치되는 영구적인 해양구조물기초의 한 형태이다. 인발에 대한 정착하중을 증가시키기 위해, 3개의 수직플랜지가 120도의 간격으로 앵커표면을 따라 부착되어있다. ESA 거동에 영향을 미치는 여러 매개변수의 영향을 찾기 위해 고안된 분석적 해법을 이용한 분석적 매개변수 연구가 이루어졌다. 분석의 결과는 앵커의 매입깊이와 흙의 강도가 증가할 때 ESA의 부담하중도 증가하는 것으로 나타났으며, 그리고 하중 경사각이 증가할 때는 감소하는 것으로 나타났다. 또한 사각형의 투영된 면적을 가진 ESA는 앵커길이의 중심에서 수평적으로 인발될 때 가장 큰 인발력을 갖는 것으로 나타났다.