• Journal of the Korean Geosynthetics Society
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• v.23 no.2
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• pp.29-42
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• 2024

The 2017 Pohang earthquake caused damage to quay structures due to liquefaction. Liquefaction occurs when effective stress is lost due to an increase in excess pore water pressure during an earthquake. As a result, the damage caused to the pier-type quay wall was identified and the damage caused by liquefaction was analyzed. In addition, in the case of improved ground, damage occurred due to liquefaction of the lower sand layer due to the difference in stiffness from the soft rock layer, so additional numerical analysis was performed assuming non-liquefaction ground. There are several factors that affect the increase in excess pore water pressure ratio, such as the relative density of the ground and the magnitude of the input seismic acceleration. Therefore, this study performed numerical analysis for Cases 1 to 3 by increasing the magnitude of the input acceleration, and in the case of improved ground, damage occurred due to liquefaction of the lower sand layer, so the analysis was performed assuming non-liquefaction ground. As a result, the improved ground requires additional reinforcement when there is liquefied ground below, and the horizontal displacement of the pier-type quay piles was reduced by about two times.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.61-67
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• 2008

This study analyzes the characteristics of material transportation between Busan new-port and Nakdong river estuary. Measurements of water temperate, salinity, turbidity, and tide is also analyzed to determine the characteristics of sea water and described the tidal current between two regions. For the purpose of indicating characteristics of tidal current numerical modeling is used. From the observed results, the total volume transport of sea water calculations revealed $184.71m^3/sec$ and residual volume transport was $(+)59.74m^3/sec$ during the 1st field measurement, and the total volume transport was $331.15m^3/sec$ and residual volume transport was $(-)28.88m^3/sec$ during the 2nd. The numerical simulation for three different topography cases are calculated. The results are summarized as follows: 1) The volume of material transportation about $0.7\sim18.4%$ is decreased as the depth of Busan new-port decrease (10 m). 2) The volume of material transportation about $3.5\sim21.9%$ is increased, as channel(water depth is 5 m) constructed to the Nakdong river estuary direction.

• Journal of the Korean Geotechnical Society
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• v.38 no.9
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• pp.5-17
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• 2022

Recently, several studies have been conducted on virtual fixed-point and elastic soil spring methods to simulate the soil-pile interaction in response to spectrum analysis of pile-supported structures. However, the soil spring stiffness has not been properly considered due to the seismic load magnitude, and studies on the response spectrum analysis of pile-supported structures considering this circumstance are inadequate. Therefore, in this study, the response spectrum analysis was performed considering the soil spring stiffness according to the seismic load magnitude, and the dynamic behavior of the pile-supported structure was evaluated by comparing it with existing virtual fixed-point and elastic soil spring methods. Comparing the experiment and analysis, the moment differences occurred up to 117% and 21% in the virtual fixed-point and elastic soil spring models, respectively. Moreover, when the analysis was performed using an API p-y curve considering the soil spring stiffness according to the seismic load magnitude, the moment difference between the experiment and analysis was derived at a maximum of < 4%, and it is the most accurate method to simulate the experimental model response.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.6
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• pp.138-145
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• 2023

A study using numerical analysis techniques was conducted to examine the scour effect of pier-type dolphin structures installed in the domestic marine environment, and the effect of scour on horizontal bearing capacity was examined. In this study, we designed the berthing structures, taking into account the environmental and ground conditions of the target maritime area, and after calculating the predicted scour area, stability evaluation was performed by removing the ground elements of the area. The increase in scour depth was found to induce a direct decrease in horizontal bearing capacity due to soil loss in contact with the foundation, establishing a relationship that increases horizontal displacement. However, in the foundation designed to withstand the design load by reflecting the safety rate, the increase in horizontal displacement formed by possible scour is not large, which did not have a dominant effect on the horizontal bearing capacity of the foundation. In the future, research is required to analyze the impact of each factor and formalize evaluation and design techniques to evaluate the scour safety of marine foundations and pier-type structures installed in various ground conditions and structural formats.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09a
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• pp.220-223
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• 2008

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09a
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• pp.25-27
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• 2008

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09b
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• pp.25-27
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• 2008

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 2008.09b
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• pp.220-223
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• 2008

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.141-150
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• 2004

Shaking table model tests were performed to reproduce the dynamic behavior of a gravity quay wall and a pile-supported wharf which were damaged during the Kobe earthquake in 1995. The results of the model tests were compared with field measurements and with the results of previous model tests. The displacements of the model quay wall were only one third of that of the prototype, whereas the deformation state of the model was similar to that of the prototype. The displacements of the model pile-supported wharf were about two thirds of that of the prototype and the locations of the maximum moments at the model pile were similar to the buckling locations of the prototype piles.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.82-88
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• 2004

To evaluate the tidal flow around the transmission type harbour structures, the numerical models considering hydraulic resistance are used. The traditional governing equations of depth-integratef hydrodynamics are modified by using of the drag force term. As a numerical model to evaluate the rate of tidal exchange, the Random-walk method is used. The models are applied in a design of the pile-supported pier structures in Busan harbour site, Korea, where the flow speed and the tidal exchange are more promotive than the case of non-transmission structure. The developed model will be applied usefully to design the transmission type structure in the ocean space.