• Ocean and Polar Research
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• 제25권spc3호
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• pp.385-392
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• 2003

A new type of soft ground breakwater was recently developed, which does not need ground improvement because of light weight and structural characteristics. The various studies about consolidation settlements and lateral behavior of proposed soft ground breakwater have been conducted. But, the systematic investigations on the construction performance and long-term settlements of new type breakwater has not been accomplished. In this study, construction simulation of soft ground breakwater with soil box model test and experiments of the long-term wave loaded breakwater were performed. The results of test shows that it is possible to compensate differential settlements by dead loading and/or suction pressure, and to reduce the consolidation settlements by preloading method. It was also found that the vertical and lateral displacements of long-term wave loaded breakwater were negligible.

• 환경위생공학
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• 제21권3호
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• pp.61-72
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• 2006

This study was carried out for verification of efficiency of seawater exchange breakwater which was installed in joomoongin harbor for the first time in our country. The joomoongin harbor, where seawater exchange breakwater has been constructed, shows typical for fishery and tourist port city specifics of greatest pollutants discharge volume in spring and summer, when tourist inflow and fishery activity is most vigorous. On the East Sea seawater flux through seawater exchange breakwater for the smallest waves (up to 0.5 m) was found out to be $1,526-3,052m^3/day$. After construction of seawater exchange breakwater, Zone 1 and Zone 2 of stagnant water inside the port were found to be a lot improved. Zone 3, adjacent to outport area, was found to be lower comparing with Zone 1 and Zone 2. The results of statistical analysis show that comparing with water quality improvement effect before and after seawater exchange, water quality after installation of seawater exchange breakwater became much better, primarily because of physical change around the harbour.

• 한국해양공학회지
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• 제10권1호
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• pp.100-107
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• 1996

In this paper, we report the results of the experimental study on the flow and the mass transport around a square harbor driven by a tidal effect. The model harbor is composed of a uniform water-depth with a straight breakwater. The harbor is connected to the outer ocean by an entrance region having the same shape as the harbor. We investigated two cases, one having another breakwater in the place between the entrance region and the outer ocean, and the other without it, The surface and bottom flow patterns of the model container are visualized by using light particles and dye, respectively. It was shown that the inner harbor and the entrance region have well-organized, large vortical residual flows, and the material transport between the entrance and outer region is however significantly different for two cases; when the breakwater is built between the two regions, the transport is far better than that without it, which is clearly contrary to our common sense that the breakwater would block the dispersion of the materials between the harbor and the outer ocean.

• 한국수자원학회논문집
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• 제39권11호
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• pp.961-968
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• 2006

소규모 항만은 주로 쇄파대 근방에 건설되는 경우가 많기 때문에 표사이동에 의한 퇴적영향에 의해 항내매몰이 발생될 가능성이 크다. 본 연구에서는 평면수조를 이용한 수리모형실험을 통해, 투과형방파제를 적절히 설치할 경우에 있어서의 소규모 항만의 항입구부 및 항내로의 표사이동에 대한 메카니즘을 파악하고자 하였다. 우선, 항내의 진동이 1차 모드일 때 표사이동이 증가되는 것을 실험적으로 확인하였다. 또한, 입사파의 주기가 단주기일 경우에는 항내의 진동이 고차 모드가 되고, 항내측으로의 표사이동은 감소되는 경향을 나타내었다. 부(副)방파제 선단에서 발생되는 와류가 항내로의 표사이동의 주된 원인인 것을 확인할 수 있었고, 부방파제 선단 외측에 소돌제를 설치함으로써 와류를 감소시켜 항내로의 표사이동을 억제하는 효과가 있는 것을 확인하였다.

• 한국항만학회지
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• 제13권2호
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• pp.399-408
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• 1999

Copeland’s(1985) hyperbolic mild-slope equation including diffraction refraction and reflection in the wave field is used as a governing equation in this study. The result of Maruyama & Kajima(1985) is used to calculate wave direction and that of Watanabe & Maruyama(1986) is used as a energy dissipation formula. Numerical solutions are obtained by the Leap-Frog scheme and compared with Watanabe & Maruyama’s (1984) hydraulic experimental results and numerical simulation results for the detached breakwater. This wave model is applied to a detached breakwater and compared with Watanabe and Maruyama’s (1984) hydraulic model results to check the characteristics of reflected wave field around a detached breakwater. The distribution of wave height and we phase in front of a detached breakwater is more accurate than the Watanabe and Maruyama’s numerical results. The results from our wave model show good agreements with the others and also show nonlinear effects around the detached breakwater. This model is applied to the Gamcheon harbor of pusan. the field observations were carried out at Pusan harbor wave station in 1986-1995 and the results were accepted as a design wave condition in this study. The wave height and wave period was measured by Dong-A university at one station in the Gamcheon harbor in 1996-1997 and used as a calibration criterion. The measured data were used as input data for the numerical simulation and also compared with simulated results. The numerical simulation shows a fairly good results which considering the effect of topographic characteristics and effect of narrow entrance due to two separated breakwaters in Gamcheon harbor. The wave distribution characteristics inside Gamcheon harbor is quite different with the offshore wave direction and wave period.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.449-452
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• 2006

The main external force of the harbor in east coast is wave. So, wave is the important cause of wave induced current and sediment transport due to wave in planning harbor structures. Therefore, it must be considered not only to secure the harbor tranquility but also the sediment transport due to wave induced current in planning the harbor. In this study, we studied on the influences of construction procedure on harbor tranquility and siltation using annual coastal line data and bathymetry data near breakwater. And it suggests that the construction procedure for the harbor tranquility and the best way for the decrease of harbor siltation.

• 한국해안해양공학회지
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• 제14권1호
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• pp.76-85
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• 2002

부유식 방파제는 고정식 방파제에 비하여 항 내·외 해수교환성은 우수한 반면, 항내 정은도가 다소 저하되는 특징이 있다. 따라서, 설계초기단계에서 부유식 방파제의 여러 평면배치 대안에 대하여 항내 정온도를 적절히 평가할 필요가 있다. 본 연구에서는 기존의 시간의존완경사 방정식을 부유식 방파제 설치안에 대해서도 적용할 수 있도록 하기 위하여 부유식 방파제의 반사와 투과를 동시에 반영할 수 있는 일종의 반사-투과 경계조건을 정식화하였다. 본 경계조건의 성능을 검토하기 위하여 이차원 및 삼차원 해석을 수행한 결과, 수치해석에 입력된 반사 및 투과율이 수치적으로 잘 구현됨을 확인하였다. 마지막으로 본 반사-투과 경계조건을 부유식 방파제가 설치되어 있는 가상적 항만에 적용하였으며, 본 수치해석이 부유식 방파제의 실해역 설치를 위한 실무에서도 충분히 효과적으로 이용될 수 있음을 예시하였다.

• Ocean and Polar Research
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• 제25권spc3호
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• pp.347-351
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• 2003

A new approach to reliability analysis of rubble mound breakwater using neural network is proposed. At first, a neural network model which can estimate the stability number of any breakwaters for some design conditions is trained. Then, the neural network model is integrated with Monte Carlo simulation technique in order to calculate probability of failure for the breakwater. The proposed technique is compared with conventional approach using empirical formula.

• 한국지반공학회논문집
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• 제21권1호
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• pp.29-41
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• 2005

우리나라의 소규모 항만이나 어항인 경우에 설계파는 낮지만 지반조건이 좋지 않은 경우가 많기 때문에 기존의 방파제 축조공법을 이용할 경우 비용이 커질 뿐만 아니라 건설재료의 확보가 어려운 실정이다. 따라서 설계파가 비교적 낮은 경우에 저렴하게 적용할 수 있는 새로운 형식의 방파제에 대한 수요가 증가함에 따라, 본 연구에서는 지반에 대한 특별한 처리 없이 간편하게 설치할 수 있는 가로널식 방파제를 개발하였다. 이 논문은 개발된 가로널식 방파제에 대해 방파제의 근입깊이 및 보강기법, 배치 형태 등 다양한 조건에 따른 방파제의 횡방향 거동을 분석한 것으로 이를 위해 느슨한 모래지반을 대상으로 모형 토조실험을 수행하였다. 실험 결과, 근입깊이 이외에도 경사 버팀보나 앵커등 보강재의 효과 및 방파제 배치 형식에 따른 경향을 확인하였다.

• Ocean and Polar Research
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• 제25권spc3호
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• pp.393-397
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• 2003

The seawater exchange breakwaters can be effectively employed to conserve or enhance the water quality inside harbors by transmitting the exterior water into the harbor. In the present study, three shapes of the breakwater, that is, the flow conduit embedded type, the wave chamber type and the oscillating water channel type are compared far their water exchanging capability through regular wave experiments. The results show that the net influx of water appears differently depending on wave period for each breakwater type. The net influx of the wave chamber type is much greater than that of the flow conduit embedded type. It is also ascertained that the influx of the oscillating water channel type can be greatly enhanced by attaining the resonance condition inside the channel at the wave periods frequently occurring at the fields where the breakwaters are to be installed.