• Journal of Ocean Engineering and Technology
• /
• v.18 no.1
• /
• pp.16-21
• /
• 2004

In general, core materials of rubble mound breakwater are used at a restricted range of 0.015㎥～0.03㎥. However, it is not satisfied with the standard design in over fifty percent of the cases. In this study, model tests and numerical analysis are employed to examine the range of core material that has no problem with capacity maintenance and stability of rubble mound breakwater. Model tests measure the porosities that are mixed in various ratios, to classify core materials by three parameters. The slope stability of rubble mound breakwater is investigated, using numerical analysis, with a friction angle and a unit weight. The change of unit weight, which is followed by the mixed rate of size core material, has no large affect on slope stability, and there is no problem with ensuring slope stability of the rubble mound breakwater.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2004.05a
• /
• pp.303-308
• /
• 2004

The failure at the head section of rubble mound breakwaters is more important than other failure modes. because this initial failures will occur the failure of the trunk section and lead to the instability of the structure. The three-dimensional failure modes are discussed using the experimental data with multi-directional waves considering the failure modes. It was occurred by the topographical characteristics around the head of rubble mound breakwater. The spacial characteristics of failure mode around the rubble-mound structures can be summarized as follows: 1) It was clarified that the failure modes at the round head of a detached breakwater are classified as failure by plunging breaker on the slope, failure by direct incident wave force and failure at the rubble mound breakwaters. 2) The failure mode was found in the lower wave height than the design wave by the breaker depth effects and topography around structures. It is clarified that the structure was monitored safely designed for the design wave but the failure was occurred by the reason of breaker waves.

• Journal of Industrial Technology
• /
• v.21 no.B
• /
• pp.163-174
• /
• 2001

A dynamic reliability model for analyzing the stability of armor units on rubble-mound breakwater is mathematically developed by using Hudson's formula and definition of single-failure mode. The probability density functions of resistance and loading functions are defined properly, the related parameters to those probability density functions are also estimated straightforwardly by the first-order analysis. It is found that probabilities of failure for the stability of armor units on rubble-mound breakwater are continuously increased as the service periods are elapsed, because of the occurrence of repeated loading of random magnitude by which the resistance may be deteriorated. In particular, the factor of safety is incorporated into the dynamic reliability model in order to evaluate the probability of failure as a function of factor of safety. It may thus be possible to take some informations for optimal design as well as managements and repairs of armor units on rubble-mound breakwater from the dynamic reliability analyses.

• Journal of Ocean Engineering and Technology
• /
• v.17 no.6
• /
• pp.23-31
• /
• 2003

As there are so many uncertainties associated with using the determinism analysis method in the design of rubble mound breakwater, it is impossible for a designed construction to provide ultimate stability. First of all, due to the uncertainty of Load and Resistance, a safety level concerning the destruction mode of construction must be given. Then, the optimization design should be processed. After all, we can say that it is a more reasonable design method than the design used by the stability rate. In this study, an established design process is accomplished using Hudson's equation and an economic analysis with the breakwater's section is also conducted. Hudson's equation is compared to Van der Meer's equation. These results are utilized to drop a damage rate, increase the stability of construction, and determine the optimization section of the breakwater.

• Ocean Systems Engineering
• /
• v.3 no.1
• /
• pp.55-70
• /
• 2013

A composite breakwater with an upper horizontal porous plate and a lower rubble mound is proposed and studied in this work. By means of matched eigenfunction expansions, a semi-analytical solution is developed for analyzing the hydrodynamic performance of the breakwater. The semi-analytical solution is verified by known solutions for special cases and an independently developed multi-domain boundary element method solution. Numerical examples are given to examine the reflection, transmission and energy loss coefficients of the breakwater and the wave force acting on the horizontal porous plate. Some useful results are presented for engineering applications.

• 한국방재학회:학술대회논문집
• /
• 2008.02a
• /
• pp.217-220
• /
• 2008

The reflection coefficients and the run-up heights affected by submerged structures are studied by using the numerical and the laboratory experimental methods. The three-point method is chosen to calculate the reflection coefficients in both the experimental and the numerical methods. The results of numerical simulations are shown a good agreement with laboratory measurements. The reflection coefficients increase and the run-up heights decrease when the rubble mound breakwater is defended by low-crested structures.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.12
• /
• pp.85-96
• /
• 2011

A breakwater is a important structure for both calmness of harbor and protection of the port facilities from waves generated from typhoons or wind. This study adopted the rubble mound breakwater, which is one of the most popular type of breakwaters in Korea. Rubble mound breakwater had been designed by considering only static condition previously. Recently, a dynamic wave-load due to waves has been also considered in designing breakwater. In design, the wave-load is assumed as an uniform load which only acts in the front slope of the breakwater. However, the assumption is not applicable in reality. In this study, therefore, a real-time wave-load acting on the breakwater instead of the uniform load is considered, and it is assumed to be acting on the seabed too. Based on the numerical analysis, it is found that there is a significant difference in the maximum settlement compared with the result predicted by the existing design method.

• Journal of Ocean Engineering and Technology
• /
• v.17 no.6
• /
• pp.16-22
• /
• 2003

In this paper, the method of determining the economically-optimal design section of rubble mound breakwater, using ADS program, was studied to supplement the deterministic approach. First of all, the design waves are computed, according to the return periods, using the Weibull distribution from the data of waves at the location of the breakwater. In order to take an optimal section, according to the return periods, the ADS program was used. The restriction conditions and objective functions are decided from the references of the specifications and standard manuals for Coastal and Harbor Construction Work. Results from this study support the ADS program as an appropriate method for determining the economically-optimal section of rubble mound breakwater, comparing the construction costs and the initial and damage repair costs for its life time.

• Journal of Korean Port Research
• /
• v.8 no.2
• /
• pp.57-65
• /
• 1994

A theoretical formulation is performed to investigate the wave reflection and transmission ratios by a submerged multi-layered rubble-mound breakwater. This theory, which is based on the linear boundary integral method, can be extended to the multi-layered breakwater with arbitrary cross section. In the theoretical analysis evanescent mode wave is not considered, since fictitious open boundaries are put on the places far from the structure. Therefore the mathematical presentation may be simpler, and computational time shorter. The validity of obtained numerical results is demonstrated by comparing with ones of impermeable and permeable breakwaters. Comparison shows resonable agreement. On the basis of these verifications this theory is applied to the one and two-layered submerged rubble-mound breakwater with trapezoidal type.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.20 no.4
• /
• pp.413-420
• /
• 2008

Wave force is an important factor which gives a direct affect to stability of the rubble mound breakwater. Particularly wave force has been considered as the main cause of displacement for replaced rubble mound breakwater which permits a little displacement to some degree. But the effect on displacement by wave force has not been considered and reflected in design. Therefore in this study, we compared numerical analysis displacement with field measured displacement so that the effect of wave force on displacement can be reflected in design. Result of the numerical analysis displacement was well consistent with field measured displacement data.