• Strategy21
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• 통권37호
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• pp.193-241
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• 2015

China, Japan and Korea are the world's top 10 energy consumers, and so very interested in the development of seabed hydrocarbon resources in order to meet their energy demands. The East China Sea is the tri-junction area where three countries' entitlements on the maritime boundaries are overlapped. There are abundant oil reserves in the East China Sea, and therefore competitions among countries are growing to get control of them. Although these countries have concluded the bilateral agreements to jointly develop resources in the East China Sea, they do not function as well. Because joint development and management of seabed petroleum resources can lead to stable development system, and to lower possibility of legal and political disputes, the needs for joint development agreement among three countries are urgent. Meanwhile, Northeast Asian seas are semi-closed seas, which are geographically closed and vulnerable to marine pollution. Moreover there are a lot of nuclear power plants in coastal area, and seabed petroleum resources are being developed. So it is likely to occur nuclear and oil spill accidents. Fukushima nuclear disaster and Bohai Bay oil spill accident in 2011 are the cases to exhibit the potential of major marine pollution accidents in this area. It is anticipated that the risks become higher because power plants and offshore oil platforms are extending gradually. Therefore, the ways to seek the joint marine environmental protection agreement focused on regulation of nuclear power plant and offshore oil platform have to be considered. In this paper, we try to find the way to make joint development and joint environmental protection agreement in Northeast Asian seas. We concentrate on the measure to drive joint development of seabed petroleum deposits in East China Sea's overlap area, despite of maritime delimitation and territorial disputes, and we try to drive joint marine environmental protection system to respond to marine pollution and accidents due to offshore oil platform and nuclear power plants. Through these consideration, we seek solutions to deal with lack of energy, disputes of maritime territorial and boundary delimitation, and marine pollution in Northeast Asia.

• 자원환경지질
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• 제49권2호
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• pp.121-134
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• 2016

서태평양 공해 해저산의 다중빔 음향측심자료와 해저면 영상관측 자료를 활용하여 해저산 정상부와 경사면에 피복된 망간각의 공간 분포 변화 양상을 파악하였다. 다중빔 음향측심기를 이용하여 구분된 해저산의 지형 특성은 정상부 면적의 약 70% 이상이 경사가 $5^{\circ}$ 미만으로 비교적 평평한 지대로 이루어져 있으나 후방산란강도는 해저면의 매질변화를 지시하는 이봉분포를 보였다. 이 이봉분포에서 -30 dB이상의 높은 최빈값은 경사면과 정사부 가장자리 지역에서 우세하였으며 -30 dB이하의 낮은 최빈값은 정상부 중앙지역에서 우세하였다. 해저면 표층의 영상자료와 후방산란 자료의 연관성을 분석한 결과, 정상부 중앙지역은 경사면에 비해 상대적으로 완만한 기울기와 미교결 퇴적물만 존재하여 후방산란이 낮게 나타난다. 반면, 정상부 가장자리 및 경사면은 퇴적물이 없어 기반암이 노출되거나 망간각이 피복되어 후방산란이 높게 나타남을 보여준다. 따라서 다중빔 음향측심조사를 통해 획득된 후방산란 자료와 해저면의 퇴적물 및 망간각 분포 사이의 상관관계가 높다는 것을 알 수 있다. 이 연구결과는 다중빔 음향측심조사를 통해 획득된 후방산란 자료를 활용하면 기요형태의 해저산에 피복된 망간각의 전체적인 분포 규모를 확인할 수 있음을 의미한다. 따라서 해저산 지역의 망간각 개발 유망구역을 선별하는데 후방산란 자료가 유용하게 활용될 수 있을 것이다.

• 한국해안·해양공학회논문집
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• 제29권3호
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• pp.147-153
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• 2017

본 논문에서는 해저매설형 음향센서 시스템의 기계적 내구성을 검증하기 위한 시험 규격을 수립하고 관련 시험을 수행하였다. 음향센서 시스템은 고가의 설치 비용으로 인하여 설치 이후에 높은 신뢰성이 요구되며, 매설 장비와의 기계적 연동 중에 다양한 복합 하중이 작용하므로 높은 내구성을 갖는 설계가 요구된다. 따라서, 이러한 설계 조건을 만족하는지에 대하여 시험 규격을 수립하고 검증하는 과정이 필요하다. 본 논문에서는 UJ QTS 200 규격 기반으로 내구성 시험을 수행하여, 전기적인 특성에 대한 대부분의 시험 기준을 만족함을 확인하였다.

• 한국해양공학회지
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• 제31권3호
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• pp.219-226
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• 2017

In this study, the impact characteristics of subsea pipelines that were installed in various soil types and burial depths were evaluated by a numerical method. An impact scenario replicated a dropped ship anchor that fell vertically and impacted an installed subsea pipeline. In order to calculate the impact force through terminal velocity, FLUENT, a computational fluid dynamic program and MDM (Moving Deforming Mesh) technique were applied. Next, a dynamic finite element program, ANSYS Explicit Dynamics, was used for impact analysis between the anchor and pipeline (or, subsea if they were buried). Three soil types were considered: loose sand, dense sand and soft clay by applying the Mohr-coulomb model to the seabed. The buried depth was assumed to be 0 m, 1 m and 2 m. In conclusion, a subsea pipeline was the most stable when buried in dense sand at a depth of 2 m to prevent impact damage.

• 한국해양공학회지
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• 제28권1호
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• pp.47-54
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• 2014

When an anchor penetrates and is installed under a seabed, a portion of the mooring line connected to the anchor is also embedded under the seabed. This embedded mooring line affects the capacity of the anchor in two ways. First, the frictional resistance that occurs between the mooring line and the seabed reduces the pulling force acting on the anchor. Second, the embedded part of the mooring line forms a reverse catenary shape due to the bearing resistance of the soil, so that an inclined pulling force is applied to the anchor. To evaluate the mooring line's effect on the capacity of an anchor in sand, centrifuge model tests were performed using two relative sand densities of 76% and 51% while changing the anchor depths. The test results showed that the load is reduced much more in deep and dense sand, and the inclination angle of the load is lower in shallow and loose sand.

• Ocean and Polar Research
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• 제33권4호
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• pp.485-495
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• 2011

On February 11, 2011, upon request of the International Seabed Authority, 'the Seabed Dispute Chamber of the International Tribunal for the Law of the Sea(henceforth Chamber)' rendered its advisory opinion on the responsibilities and obligations of States sponsoring persons and entities with respect to activities in the Area. The advisory opinion covered three questions: What are the legal responsibilities and obligations of the sponsoring states with respect to the sponsorship of activities in the Area? What is the extent of liability of a State Party for any failure to comply with the LOS Convention and relevant instruments? What are the necessary and appropriate measures that a sponsoring State must take in order to fulfil its responsibilities? In particular, the Chamber delivered its opinion on the different responsibilities and obligations of developed and developing sponsoring states. This paper reviews the above three questions through analyzing the advisory opinion and makes some recommendations for the fulfillment of the responsibilities and obligations of Korea as a sponsoring states.

• 한국농공학회지
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• 제38권1호
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• pp.79-89
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• 1996

It is expected that the soil hehaviours in the seahed subjected to cyclic wave loads are much different from that on the ground Cyclic shear stresses developed below the ocean bed as a result of a passing wave train may progressively build up pore pressure in certain soils. Such build-up pore pressure may be developed dynamic behaviour such as liquefaction and significant deformation of the seabed. Currently available analytical and testing methods for the seabed subjected to cyclic wave loads are not general. The purpose of the study are to provide a test method in laboratory and to analyse the mechanism of wave-induced stresses and liquefactions potentials of the unsaturated silty marine sand. It is showed that the test set-up made especially for this study delivers exactly oscillatory wave pressures of the form of sine function. Laboratory test results defining the cyclic shear strength of the unsaturated porous medium that is homogenously sedimented. It is understood that the pore water pressure due to induced-waves is not accumulated as the wave number increases but reveals periodical change on the still water surface. The magnitude of the pore water pressure tends to be attenuated radically with a certain time lag under the action of both high and low waves as depth increases.

• 한국농공학회지
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• 제38권5호
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• pp.85-94
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• 1996

For the geotechnical analysis in the construction and Deign of the coastal structures, one of the most important factors is the existence of waves. The dynamic behavior and deformation of the seabed subjected to wave load must be considered. It is expected that the soil behavior in the seabed subjected to cyclic wave load is much different from that on the ground subjected to dynamic forces such as earthquake. The purposes of this study are as follows ; Firstly, to provide a testing method to generate wave loads in the laboratory and measuring oscillatory pore water pressures in the unsaturated marine silty sand specimen, Secondly, to analyze the mechanism of wave induced pore water pressures and liquefaction potentials under the conditions in the testing. It is shown that the test set-up manufactured especially for the test is good to generate oscillatory wave pressures to the specimen with sine wave type. From the results of this study, it is understood that the pore water pressure due to induced waves is not accumulated as the wave number increases but is periodically varied with wave passage on still water surface. The magnitude of pore water pressures measured tends to be diminished radically with a certain time lag under the action of both high and low waves as depth increases.

• 한국해양환경ㆍ에너지학회지
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• 제5권2호
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• pp.19-27
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• 2002

본 연구는 입체적 어장 개발을 위해 수산자원 증대의 토대가 되는 해조장의 확대와 생태계의 고밀도·고효율화를 위한 기초적 연구로 수평판형 중층계류식 인공해저시스템의 파랑응답특성에 관한 실험적 연구를 수행하였다. 실험은 2차원 수조에서 다른 두 가지 모형의 수평판을 세 가지 다른 수심에 각각 고정 혹은 계류시켜 실시하였다. 실험에서 모형 고정시의 작용유체력 특성과 모형 계류시의 파랑응답 및 계류력 특성을 살펴보았으며, 또 각 조건에서 모형의 파랑제어특성을 검토하였다.

• Ocean and Polar Research
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• 제36권4호
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• pp.515-524
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• 2014

The Korea Institute of Ocean Science and Technology has acquired detailed biological, chemicophysical, and geological data in the northeastern Pacific through a manganese nodule program since 1983. Plenty of manganese nodules were collected to estimate the amount of resources by free-fall grab and box corer. The collected manganese nodules have been archived systematically in the rock and mineral storage section of the Library of Marine Samples (LIMS) since 2012. The LIMS provides essencial information on the stored samples including sample name, nodule type, sampling location, depth, and equipment. Although a high quality database of the information system is under construction, the samples have tagged information for manganese nodules like chemical composition, morphology, weight, size, abundance, and photograph. In this study, we attempted to provide information on the well-organized and easily accessible archived manganese nodule samples for future studies and to introduce the usefulness of the LIMS.