• Journal of the Speleological Society of Korea
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• no.77
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• pp.31-42
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• 2007

북제주군 협재리 해안가 인근에 소재한 건지굴을 대상으로 화산지역의 용암동굴에서 특이하게 진행되고 있는 응암석회질화(鎔岩石灰質化: lava-calcification)의 위종동(僞鐘洞)에 대하여 동굴내부와 주변상황에 근거한 분석, 고찰을 통하여 석회질화의 원인을 규명하고, 생태와 환경 및 동굴해안접경구와의 상관성을 고찰하고, 주위에 흔히 분포되어있는 스코리아에 대해 분석응용을 하였다. 용암(화산)동굴은 생성이후 퇴화한다. 그러나 용암동굴에서 용암석회질화의 위종동 현상이 발생하면 용암의 기공과 균열부분 또는 용암석간의 공극에 석회질 성분이 침투, 고화, 융합되면서 구조적 보강효과의 발생으로 오히려 건축구조물의 콘크리트 역할과 같이 견고하게 진행되는 특이현상을 갖는다. 이와 같은 진행성 용암석회질화 현상이 북제주군 협재리에 소재한 건지굴에서 진행되고 있음을 최초로 확인하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.14 no.4
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• pp.319-321
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• 2002

Recently, the injection of cement stabilizer is used as one of ways to improve soft sea-bottom. However, this method makes an argument with $Cr^{6+}$subject to emerge to the seawater from the cement stabilizer. To investigate the amount of$Cr^{6+}$field measurements were carried out in Ochun harbor of Chunsoo Bay. The analysis shows the amount of $Cr^{6+}$in the seawater met the demand of environmental criterion.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.6 no.1
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• pp.61-71
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• 1994

A modified method obtained by expanding Longuet-Higgins and Stewart's method (1964) is proposed. which can easily derive the group-bountied long wave due to the irregular were group as well as the regular wave group. The result of the proposed method agree well with those of both second order nonlinear theory and radiation stress theory. Particularly in the shallow water region, three equations from the proposed method, the second order nonlinear theory and the radiation stress theory become identical.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2003.08a
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• pp.134-136
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• 2003

강원도의 연도별 수산물생산실적을 조사한 표1에서 1995년도 어패류의 총 생산량이 88,030 백만톤이었으나 2000년도의 총생산량은 60,687백만톤으로 32 ％가 감소하였다. 이렇게 어획량이 감소하게된 주요원인은 해역의 환경변화가 크다고할 수 있는데, 수면을 육지화 하므로써 그 주위에서 어떠한 환경변화가 일어날 수 있으며 환경변화에 어떻게 대처할 것인가 하는 대책도 마련하여 개발에 따른 피해영향을 최소한으로 줄이고, 손상된 환경을 복원하고, 또한 이러한 것들이 불충분한 경우에는 새로운 환경을 재생, 창조하는 방법으로서 주문진 연안의 해안선과 기상, 해상 해저 등 물리적인 조건과 생물조건을 고려하여 주문진 해역에 적합한 인공어초를 제시하여야한다. (중략)

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.5 no.2
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• pp.51-57
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• 1993

It is often assumed that the wave velocity at the bottom given by potential wave theory il the same as the wave velocity at the top of the turbulent boundary layer. This assumption is found to be the major cause of the error detected by recent elaborate theories and numerical models for the description of velocity profile near the sea bottom. A relationship is suggested between the potential velocity and the real boundary velocity. Based on this relation, the existing theories of Jonsson (1967) and Fredsoe (1984) are refined for the estimation of wave friction factor, and the computation results of the modified theories are favourably compared with the published laboratory results.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.8 no.1
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• pp.52-60
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• 1996

Existing equations of bed load transport are reviewed mainly considering the meaning and. role of variables used in the equations. The development of several equations and the problems of each equation are investigated by comparing their computed results against field or laboratory data. On the basis of the review remedies of each equation are suggested, and modified forms of existing equations are developed for wider application and improvement in the accuracy. Empirical parameters introduced in each equation are determined by testing them against Brownlie(1985)'s collected data, and discrepancy ranges of the refined equations are shown to see their degrees of accuracy.

• 한국해양학회지
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• v.23 no.2
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• pp.62-69
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• 1988

Analyzing short-term records of sea level data, we show that the amplitudes of diurnal tides along the southern coast of Jeju-Do are significantly larger than those along its northern coast. The amplitude-phase diagrams of $K_1$ and $O_1$ look very similar to that of $M_2$ shown by Kim and Lee (1986), indicating characteristics of the scattering of long waves by Jeju-Do.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.69-84
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• 2020

Natural shoreline repeats its re-treatment and advance in response to the endlessly varying sea-conditions, and once severely eroded under stormy weather conditions, natural beaches are gradually recovered via a boundary layer streaming when swells are prevailing after storms cease. Our understanding of the boundary layer streaming over surf-zone often falls short despite its great engineering value, and here it should be noted that the most sediments available along the shore are supplied over the surf-zone. In this rationale, numerical simulation was implemented to investigate the hydraulic characteristics of boundary layer streaming over the surf zone in this study. In doing so, comprehensive numerical models made of Spatially filtered Navier-Stokes Eq., LES (Large Eddy Simulation), Dynamic Smagorinsky turbulence closure were used, and the effects of turbulence closure such as Dynamic Smagorinsky in LES and k-ε on the numerically simulated flow field were also investigated. Numerical results show that due to the intrinsic limits of k-ε turbulence model, numerically simulated flow velocity near the bottom based on k-ε model and wall function are over-predicted than the one using Dynamic Smagorinsky in LES. It is also shown that flow velocities near the bottom are faster than the one above the bottom which are relatively free from the presence of the bottom, complying the typical boundary layer streaming by Longuet-Higgins (1957), the spatial scope where boundary layer streaming are occurring is extended well into the surf zone as incoming waves are getting longer. These tendencies are plausible considering that it is the bottom friction that triggers a boundary layer streaming, and longer waves start to feel the bottom much faster than shorter waves.

• The Journal of Engineering Geology
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• v.7 no.3
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• pp.217-227
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• 1997

The purpose of this study is to analyze the correlation of soil properties in coastal soft ground. For the purpose of this study, several coastal soft ground areas were selected. Many large scale construction works are being executed and will increase continuously in these soft ground areas. So, soil property in these areas is very important. The grounds forming coastal areas are affected by seawater movement. So, most of these areas consist of alluvium stratum. Therefore, soil properties of eastern and southern coastal areas are very complex. Many laboratory tests were executed with disturbed and undisturbed soil samples. Undisturbed samples were taken by using thin walled tubes and transported into the laboratory with caution, so as not to disturb the sample. The consistent rate of fine-grained content in these areas is over 90%. Also, these areas contain higher water content and clay content. Therefore, knowing these soil properties, it is possible to safely design fabrics and constructions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.3
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• pp.115-126
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• 1990

In the past, seawall and sea dike very higher than sea-water elevation had been constructed mainly to prevent the wave overtopping volume. However, the coastal zone is recently developed for the multipurpose of not only preventing from the coastal disaster but conserving the coastal environment and utilizing the coastal space. In this sense, this paper deals with the artificial reef being able to reduce the overtopping volume. Relations of the overtopping volume to the breaking wave are briefly reviewed theoretically, and fundamental factor affecting it are also obtained experimentally form the artificial reef with the irregular waves, In addition, the numerical simulation is developed to investigate the effects of spectral band width for the overtopping volume. The most effective artificial reef section to reduce the overtopping volume is proposed.