• Journal of the Korean GEO-environmental Society
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• v.13 no.6
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• pp.41-50
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• 2012

In general, it is critical that grout consistency permit the complete filling of void space without segregation of ingredients. Recently, the antiwashout agent is used on underwater grout materials for preventing the grout from the segregation in water. This study introduces a new type of antiwashout underwater and flowable grout material using viscous modifiers and its characteristics comparing with conventional grout materials in fresh and sea water. It is found that the antiwashout underwater grout both in fresh and sea water has enough strength and good resistance to segregation.

• Magazine of the Korea Concrete Institute
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• v.7 no.6
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• pp.224-232
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• 1995

Recently, in other.view of underwater concrete construction, special admixture agent of concrete has been developed for antiwashout of concrete under water with easy carrying out method in some foreign nations. They had successful cases in experiment and construction and it trend to use in many cases with many scales. However, in domestic, there was rare record in carrying out. In this paper, reference for successful results of experiment and construction about antiwashout underwater concrete, as variable add of special admixture agent and other agents. We have carried out property tests of fresh and hardened concrete, certified the properties and made the antiwashout underwater concrete have enough strength to endure with ea.sy construction. And we have decided the optimal mix proportion for antiwashout underwater concrete under standard state.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.179-187
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• 1996

Many underwater concrete structures have been constructed recently in proportion to the increase of ocean developments. The research for the underwater concrete construction was mainly focused in view of placing method. Recently, special admixture agents of concrete were developed for antiwashout concrete under water in some foreign nations. They had successful results in experiments and site constructions. However. there are seldom experimental results or placements in domestic contry. In this paper. We had carried out property tests of fresh and hardened concrete with refer to successful results in experiments and site construction and investigated the physical variation of the antiwashout underwater concrete considering the interaction between antiwashout admixture and other ones. We have decided the optimal mix proportion fb;r antiwashout underwater concrete under standerd sea state.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.164-166
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• 2019

수중에 부유식으로 계류하는 규모와 생활지원 하중요건을 임의 가정한 수중가옥(함체)의 정수압적(hydrostatic) 계류안정성과 시공성 고찰을 목적으로 한다.

• Explosives and Blasting
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• v.38 no.4
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• pp.46-52
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• 2020

Although anti-washout grouts are used extensively in underwater targets, major constraints continue to be associated with their use. These include poor bonding strength, poor pumpability, and loss of high strength in everyday engineering applications. In this study, based on the literature pertaining to self-compacted, non-dispersive, anti-washout grouts, a review of research trends in anti-washout grouts for underwater construction and sealing of karst cavities was carried out in order to determine the problems faced in this field. Grouts used under water suffer a loss of strength and bonding strength in comparison to grouts cast in air. Researchers are designing high-viscosity grouts to overcome the inrush of water and seal karst cavities; however, in doing so, they have inadvertently caused serious problems pertaining to the pumpability of these grouts and concretes in deep target locations. Thus, the majority of the anti-washout grouts and concretes that have been developed are not applicable to deep target environments, instead being suitable for only near-surface targets.

• The Magazine of the IEIE
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• v.38 no.7
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• pp.30-36
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• 2011

최근 들어 녹색 성장과 해양 개발에 맞는 다양한 목적의 해양 구조물이 계획 또는 시공되고 있으며, 대형 해양 구조물에 대한 수요를 바탕으로 해양 구조물이 점차적으로 대수심 조건으로 옮겨가고 있는 추세이다. 이에 따라 미래 시장 예측을 통한 해양 구조물 수요 변화에 대해 미리 대처하고 미래해양구조물 니즈에 적극적으로 부합할 수 있는 방향으로 해양구조물 시공장비, 특히 수중로봇의 연구개발이 이루어져야 한다. 이 논문에서는 미래 해양구조물에 대한 개발 동향과 함께, 이에 따라 필요한 수중시공로봇의 역할과 기존의 개발 현황, 그리고 최근 기획사업을 통해 도출된 향후 연구개발 방향에 대한 분석내용을 소개하고자 한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.130-133
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• 2019

수중(submerged)에 부유(floating)식으로 계류되는 거주목적의 구조체 설계(design basis) 관련 연구로서 계류안정성 모델(수중가옥)을 만들고 거동을 정수압적 유체역학적으로 수치분석한다. 임의 가정한 수중가옥의 1)배수량 규모 2) 함체형상에 따른 환경압 하에서의 계류안정성을 a)부력중심, b)무게중심과 가변하중의 변위에 따른 c)함체 기울기를 MATLAB프로그램을 이용하여 산정한다. 나아가 수중가옥의 동적(hydrodynamic) 계류안정성을 임의 시공 장소인 독도의 기상청 울릉도-독도 부이 최근 관측치를 근거로 OrcaFlex프로그램을 이용하여 분석하므로써 수중가옥의 수중건축 시공간상 계류안정성 설계요건(design basis)을 구체화 한다.

• Explosives and Blasting
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• v.36 no.2
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• pp.27-35
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• 2018

This study introduces a suggested underwater blasting method in contrast with conventional underwater blasting methods which adopt the drilling and charging procedures by divers. A structural underwater charging system makes it possible to drill into underwater bedrock and charge explosives on the deck of barge ship. The applicability and effectiveness of the suggested method was experimentally approved by comparing with a kind of underwater charging system as a conventional underwater blasting method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.372-378
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• 2016

A mound was constructed to install a caisson and sofa blocks underwater. The mound riprap, which were of uniform grade, size, shape, and specific gravity, formed the foundation for the support superstructure. Also, rubble leveling works were performed before installing structures such as caissons. In this study, underwater construction equipment was developed with a remotely controlled operating system and underwater environment monitoring system for unmanned underwater rubble leveling work. The performance of the developed equipment was verified using on-land and underwater tests. In addition to the performance verification, the construction process and economic efficiency of the equipment should be checked before applying it to the real construction field for commercial purposes. In this paper, a construction process using the developed equipment was proposed and compared with the existing rubble leveling method. The results demonstrated that the new construction method has higher economic efficiency and safety than the existing construction method.

• Explosives and Blasting
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• v.33 no.2
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• pp.25-39
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• 2015

The common underwater rock removal methods involve underwater blasting and crane's chisel dropping impact method. From an environmental point of view, these methods cause ground vibrations and underwater noise. At the site for this study, a method of dropping heavyweight chisel is selected to remove the underwater bedrock near the ferry rack in the course of improving the cargo handling ability of the loading dock. A prediction formula for the vibration was obtained based on the measurement and evaluation of the vibrations caused by the chisel dropping impacts during the test droppings. The prediction formula was successfully applied to the main construction for securing the stability of the structure.