석션파일의 조합하중 지지력 및 압밀거동에 관한 수치해석 연구

유충식,홍승록 한국지반공학회 2014 한국지반공학회논문집 Vol.30 No.1

This paper presents the results of a numerical investigation on the load carrying capacity and consolidation behaviorof suction piles. Three dimensional numerical models which reflect realistic ground conditions and installation proceduresincluding the ground-suction pile interface were adopted to conduct a parametric study on variables such as thelength-diameter ratio and the loading configurations, i.e, vertical, horizontal, and combined loads. The results indicatedthat the load carrying capacity of a suction pile can only be realistically obtained when the interface behavior betweenthe suction pile and the ground is correctly modeled. Also carried out was the stress-pore pressure coupled analysisto investigate the consolidation behavior of the suction pile after the application of a vertical loading. Based on theresults, failure envelops and associated equations were developed, which can be used to estimate load carrying capacityof suction piles installed in similar conditions considered in this study. The results of consolidation analysis based onthe stress-pore pressure coupled analysis indicate that no significant excess pore pressure and associated consolidationsettlement occur for the loading configuration considered in part due to the load transfer mechanism of the suction pile.

석션파일 지반관입중 리프팅케이블 장력에 의한 수직도보정 효과

박해용(Haeyong Park),오명학(Myounghak Oh),강현(Hyoun Kang) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.2

Performance on the individual length control method of lifting cables for correcting verticality during suction penetration of pile was evaluated. Model tests were performed to compare and analyze for verticality correction results and cable tension for different number of installed lifting cables and inclination condition. Model test results showed that verticality of suction piles were successfully corrected during penetration by eccentricity resulted from different cable tension induced by differently adjusted length of each cables according to inclination position. Field tests were performed to evaluate field applicability. The inclination of pile was corrected by lifting cable length control during penetration. Especially, the verticality correction at the pullout stage was more effective compared with suction penetration stage in spite of slight pullout. Therefore, individual control of lifting cables during suction penetration can be applied for verticality correction of suction pile. And the accurate verticality of pile could be achieved by adding pullout process during penetration of suction pile.

Centrifugal Model Behavior of Laterally Loaded Suction Pile in Sand

장연수,김유석 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.5

A series of centrifugal tests were conducted to evaluate the maximum horizontal pullout capacity of a suction pile embedded in sand by varying the diameter and the length of the pile. The loading point was located at 75% of the pile length from the top, and the results were compared with the prediction equations of suction piles. As a result, it is found that the horizontal pullout capacity of a suction pile is proportional to its diameter and the square of length. The equation derived from Rankine's passive earth pressure equation predicts the test results very well. When pulling out the test pile from the left the test pile was apt to rotate clockwise, and its rotational point at the maximum pullout capacity was found to be in the upper part of the pile. In addition, on the basis of the center of the suction pile, the vertical displacements for all the cases appeared to develop toward the ground surface.

Numerical analysis of suction pile behavior with different loading locations and displacement inclinations

Kim, Dongwook,Lee, Juhyung,Nsabimana, Ernest,Jung, Young-Hoon Techno-Press 2012 Ocean systems engineering Vol.2 No.3

Recently, interest of offshore structure construction in South Korea is growing as the land space becomes limited for further development and the renewable energy grows to be more attractive for the replacement of the fossil energy. In order for the optimal construction of optimum offshore floating structures, development of safe and economical offshore foundation technologies is a priority. In this study, the large-deformation behavior of a suction pile, which markets are rapidly growing nowadays, is analyzed for three different loading locations (top, middle, and bottom of the suction pile) with three different displacement inclinations (displacement controlled with displacement inclinations of 0, 10, and 20 degrees from the horizontal). The behavior analysis includes quantifications of maximum resistances, translations, and rotation angles of the suction pile. The suction pile with its diameter of 10 m and height of 25 m is assumed to be embedded in clay, sand, and multi layers of subsea foundation. The soil properties of the clay, sand, and multi layers were determined based on the results of the site investigations performed in the West sea of South Korea. As analyses results, the maximum resistance was observed at the middle of the suction pile with the displacement inclination of 20 degrees, while the translations and rotations resulting from the horizontal and inclined pullouts were not significant until the horizontal components of movements at the loading points reach 1.0 m.

수평방향 하중을 받는 석션파일 기초의 분석

서민영,이준신,유무성 한국풍력에너지학회 2017 풍력에너지저널 Vol.8 No.1

These days a suction pile is one of the common options for offshore wind turbine foundations. Offshore windturbines are mainly affected by lateral loads. Therefore lateral displacement analysis of laterally loaded suctionpile is necessary to design a suction pile. In general, FEM is used for lateral load analysis but it requiresrelatively long time. Thus if response of a suction pile for lateral loads can be obtained in the closed formsolution, design of a suction pile foundation can be conducted easily. In this work, the response of laterallyloaded suction pile is suggested in the closed form solution. The closed form solution is obtained as a functionof slenderness ratio and it is compared with FEM result. The difference between the closed form solution andthe FEM result is 10.6% in average. However, the error in specific slenderness ratio range is increased up to27%.

해상풍력 석션파일의 수직도 제어에 대한 수치해석

김병완(Byeongwan Kim),김유석(Youseok Kim),진병무(Byeongmoo Jin),배경태(Kyung-tae Bae),윤희정(Heejung Youn) 한국지반환경공학회 2016 한국지반환경공학회논문집 Vol.17 No.9

본 연구에서는 점성토와 사질토 지반에 관입된 해상풍력 석션파일의 수직도 제어를 모사하기 위해 유한요소해석 프로그램인 ABAQUS를 이용하여 수치해석을 수행하였다. 석션파일은 연직방향으로부터 1° 기울어져 지반에 관입된 상태로 3차원으로 모델링 했다. 수직도 제어를 위해 석션파일 내부를 3개의 격실로 분리하고 그 중 한 격실의 상부슬래브 무게중심에 하중을 재하시켜 석션파일을 원위치 시키도록 모사했다. 수치해석 결과로부터 석션파일을 원위치 시키는데 필요한 소요 석션압을 경사도에 따라 구했으며, 원위치 시켰을 때 발생하는 석션파일 콘크리트 스커트의 최대/최소 주응력과 강재 내부격벽의 Mises 응력을 검토했다. 경사진 석션파일을 원위치 시키기 위해 필요한 소요 석션압은 점성토에서 약 410kPa, 사질토에서 약 1,800kPa로 나타났으며, 석션파일 스커트와 내부격벽에 발생하는 응력도 사질토에서 더 큰 것으로 나타났다. Numerical analyses were carried out to simulate tilting control on the suction pile for offshore wind power embedded into cohesive soil and cohesionless soil using finite element software, ABAQUS. A 3-dimensional suction pile was modelled as a wished-in-place pile with 1° tilted from vertical line. The inner room of suction pile was divided into 3 separate rooms for tilting control, and point load was applied to the center of gravity of a separate room to restore the original position of the suction pile. From numerical analyses, required suction pressure was obtained for desired tilting degree, and the maximum/minimum principle stresses of concrete skirt and the Mises stresses of inner steel wall were collected at original position. It was found that the required suction pressure was about 410 kPa for cohesive soil, and about 1,800 kPa for cohesionless soil.; likewise, obtained stresses were greater for cohesionless soil than cohesive soil.

Analytical Parametric Study on Pullout Capacity of Embedded Suction Anchors

Sorrawas Boonyong,박기철,김인철 한국해안,해양공학회 2015 한국해안해양공학회 논문집 Vol.27 No.3

The Embedded Suction Anchor (ESA) is a type of permanent offshore foundation that is installed by a suction pile. To increase the loading capacity against pullout, three wings (vertical flanges) are attached along the circumference at 120 degrees apart. Analytical parametric study using the proposed analytical solution method has been conducted to identify the effects of several parameters that are thought to influence the behavior of ESAs. The analysis results show that the pullout capacity increases as the anchor depth and the soil strength increase, and decreases as the load inclination angle increases. The anchor having square projectional area and being pulled horizontally at the middle of its length provides the highest pullout capacity.

천해역 점성토 지반에 적합한 오탁방지막 기초 앵커

권기철(GI-CHUL KWEON),홍남식(NAM-SEEG HONG),송무효(MU-HYO SONG),최창규(CHANG-GYU CHOI) 한국해양공학회 2003 韓國海洋工學會誌 Vol.17 No.3

The Navy has tested the holding capacity of many kinds of anchors in order to propose the design chart for the holding capacity of drag-embedment anchors. The design chart is only applicable up to the cable bottom angle 6° when load is raised to the ultimate weight. However, the anchor experiences a significant uplift force when the angle is above 6° in shallow seas. In this paper, the procedure for the estimation of the holding capacity of anchors in mud is proposed. Drag-embedment anchors do not function well when there is a significant uplift component of load in soft seafloor materials, such as mud. Under these loading and seafloor conditions, gravity anchors seems to be more efficient. However, they are too heavy for their holding capacity. Therefore, suction pile (hollow concrete block) is more beneficial to the foundation of silt protector in shallow sea with mud seafloor materials.

Verification of Laboratory Model Testing and Calibration of Suction Pile Installation in Sand

박기철,Terje Preber,김인철 대한토목학회 2010 KSCE JOURNAL OF CIVIL ENGINEERING Vol.14 No.4

As a part of the feasibility study of the Mobile Offshore Bases, suction piles are currently being studied to provide the necessary mooring capability. This paper presents the results of a series of suction pile installation tests performed in a model tank consisting of 59.2 cm diameter and 176.8 cm height. Suction piles ranging in diameter from 15.9 cm to 29.8 cm were tested with various surcharge weights and initial pile penetration depths in loose through medium sand conditions to measure the relationship between the applied suction pressure inside the pile and the resulting pile penetration from the beginning till the complete installation. The results have been used to verify the laboratory model testing and calibrate the mobilized soil friction angle included in the analytical solution of the suction pile installation, i.e., the suction pressure vs. pile penetration relationship. This mobilized soil strength is described as a function of non-dimensional parameters characterizing the variation and transition of the soil strength during pile installation. The non-dimensional parameters include all pertinent pile and soil parameters that are thought to govern the pile behavior during installation.

수치해석을 이용한 그룹형 석션파일의 수평방향 지지거동 분석

이주형,이시훈,김성렬 한국지반공학회 2013 한국지반공학회논문집 Vol.29 No.11

Recently, several researches on the development of new economical foundation types have been performed to supportfloating structures as many offshore structures have been constructed. This study focused on the evaluation of bearingcapacity of group suction piles, which are connected by a concrete pile cap. The offshore floating structures are mainlysubjected to horizontal loading, so the horizontal bearing capacities of the group suction piles were analyzed by performing3-dimensional finite element analyses. The group suction piles are expected to behave as a rigid pile due to its shallowembedded depth. Therefore, the detailed soil modeling was necessary to simulate the bearing behavior of soils underlow confining pressure. The modulus and the strength of soils were modelled to increase with effective confining pressurein soils. For the parametric study, the center-to-center spacing between piles was varied and two soil types of clayand sands were applied. The analyses results showed that the yielding load of the group pile increased with the increaseof the pile spacing and the yielding load of the group piles with 5D spacing was about 3 times larger than that ofthe single pile with free rotation.