{"title":"Formulation of Anchor and Chain Specifications for Establishing Subsea Cable Burial Depth","authors":"Jeonghun Kim, Insik Chun, Haneul Kang","doi":"10.20481/kscdp.2023.10.3.85","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.3.85","url":null,"abstract":"The penetration of ship anchor, which is a very important factor considered in the design stage of subsea cable burial, is highly dependent on the geometrical specifications and shapes of the anchor and chain. In order to facilitate predicting the anchor penetration depth by an arbitrary ship, formulations of the correlation between the ship mass and the existing anchor and chain specifications were attempted. In particular, for small ships with an equipment number of 40 (corresponding to DWT 90) or less, which were not covered by the existing classification data, a method for estimating the anchor mass, chain diameter, and mass per unit length was proposed.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"147 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130646348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sunghoon Hong, Seung-Nam Jin, Kyung Tae Kim, Dong-ha Kim, Jeongho Kim, Sung-Chul Jang, Hyunchul Kim, Jin Hyeok Park, H. Lim
{"title":"The Effects of Increasing Flow Velocity and Improving Water Quality in Dongsam Seawater Stream through Bi-directional Sluice Gates Operation and Tidal Range Drainage","authors":"Sunghoon Hong, Seung-Nam Jin, Kyung Tae Kim, Dong-ha Kim, Jeongho Kim, Sung-Chul Jang, Hyunchul Kim, Jin Hyeok Park, H. Lim","doi":"10.20481/kscdp.2023.10.3.95","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.3.95","url":null,"abstract":"To cope with the water pollution problem, the Dongsam seawater stream was newly renovated in 2022. For this maintenance, government constructed various facilities including electric swing sluice gates at both ends to enhance seawater exchange performance. In this regard, this study tries to quantify water velocity increment and water quality of the stream and offer suggestions for effective management. To achieve this goal, the authors performed literature review on water quality improvement, GPS buoy tracking experiments, long-term current measurement (Aquadopp), water quality monitoring, analysis of daily log data of the sluice gate. The results of this study indicate that operation of bi-directional swing sluice gates with maximum tidal range conditions can strengthen current intensity that contributes to enhance water quality of Dongsam seawater stream.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127958097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Analysis of the Navigation Criteria of Passing Vessel for the Mooring Safety in Adjacent Berth to the Fairway","authors":"Min-Jeong Lim, Ik-Soon Cho","doi":"10.20481/kscdp.2023.10.3.111","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.3.111","url":null,"abstract":"The ship wave generated by the passing ship can affect to the nearby berth and moored vessels. This can result in excessive motion of the moored ship and lead to the severing of mooring lines, potentially causing accidents. The aim of this study is to analyze the effect of passing ships navigating through the vicinity of the berth, evaluate the risks posed to the safety of moored ship, and propose safety measures. The OPTIMOOR analysis software was utilized for the assessment, with Berth A in Ulsan Port chosen as the target. The study revealed that the speed of passing ships and the separation distance between vessels significantly influence the motion of moored ships. Considering the high-risk of Berth A due to its proximity to the fairway, proposed navigation criteria for the Ulsan Port's No.1 fairway to ensure mooring safety. It has been determined that passing ships in the vicinity of Berth A should maintain a proper speed less than 8 knots, or navigate at a distance of more than 200 meters away from the dock. This study can contribute to decision-making and the establishment of safety measures in berth and fairway design.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129586751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Holding Capacity of Suction Anchor in Cohesive Soils based on Soil-Spring Model","authors":"O. Kwon, Haeyong Park, Hyoun Kang, M. Oh","doi":"10.20481/kscdp.2023.10.2.65","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.2.65","url":null,"abstract":"In this paper, a soil-spring model was applied to evaluate the holding capacity according to the loading position of the suction anchor. The API(2010) method, which is mainly applied to small-diameter piles, the PISA(2015) method, which recently introduced research results in offshore wind power design, and the Jeanjean(2009) method, which was presented as a model suitable for large-diameter piles in cohesive soil, were analyzed. A comparative review of the finite element analysis(ALE) was applied was performed for the conditions. A procedure for calculating the holding capacities for each loading position of the suction anchor was established using the soil-spring model, and it was confirmed that it was a method that could be used practically. When the soil-spring model of Jeanjean(2009) was applied, the results (5~10%) most similar to the FEM(ALE) analysis results in tendency and holding capacity could be obtained.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123755065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Choonghyun Kang, Sungnam Hong, Seung-Chul Seo, Woo-Dong Lee
{"title":"Fundamental Study on the Application of Oyster Shell as an Aggregate for Concrete in Coastal/Marine Structures","authors":"Choonghyun Kang, Sungnam Hong, Seung-Chul Seo, Woo-Dong Lee","doi":"10.20481/kscdp.2023.10.2.73","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.2.73","url":null,"abstract":"This study uses oyster shells as an aggregate substitute for marine concrete structures. The initial strength of concrete according to the proper particle size composition of the crushed oyster shell was experimentally analyzed. The particle size of the crushed oyster shell obtained through the shredder is out of the range of general aggregates' standard particle size curve because the ratio of 5 mm or less exceeds 50%. It was confirmed that if less than 5 mm was left abroad, it was within the range of the standard particle size curve, and only these were applied as thick aggregate substitutes. The crushed oyster shells impair workability due to their relatively high absorption rate. This study attempted to overcome poor workability by using two methods: using the crushed oyster shells in a saturated-surface-dry (SSD) state and adding an air entraining agent (AE). The SSD case showed that the slump increased, but the strength decreased by about 40%. The AE added case showed a slight decrease in strength while the slump more than doubled.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122032247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Long Wave Induced Monopolar Vortex: Additional Large Eddy Simulation Case","authors":"Y. Kim","doi":"10.20481/kscdp.2023.10.2.57","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.2.57","url":null,"abstract":"An additional 3D large eddy simulation with a slightly different surface tension coefficient is carried out to study the detailed flow and turbulence characteristics of a long wave induced shallow water monopolar vortex. The numerical model adopted in this study is interDyMFoam, developed based on an OpenFOAM framework. The numerical model solves filtered Navier-Stokes equations for two immiscible fluids (air, water) with a standard Smagorinsky closure. In addition to the previous model results, newly obtained instantaneous model results are used to increase a number of realizations for ensemble averaging to reach more statistically converged results. The validation quality obtained in this study is shown to be similar to that from the previous simulation results in the low-pass filtered free surface elevation and horizontal component of velocity.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126071580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Numerical Analysis for Estimating Penetration Depth by Ship-dragged Fluke Anchor","authors":"Haneul Kang, Jeonghun Kim, Insik Chun","doi":"10.20481/kscdp.2023.10.2.45","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.2.45","url":null,"abstract":"Anchor penetration by ship anchoring is emerging as a major risk factor for submarine cable. A numerical analysis method was established to predict the anchor penetration depth by ship-dragged fluke anchor in relation to setting the optimal burial depth of submarine cable. The soil resisting forces (bearing force, friction force) generated during the anchor penetration process were calculated for each of the fluke, shank and mooring chain of the anchor. The results of the numerical analysis were compared with the existing chart values of Vryhof (2015). It was found that it is desirable to use the force coefficients of strip foundation for the fluke and shank, and the force coefficients of a single vertical pile for mooring chain. The numerical analysis well reproduced the penetration trajectory in which the inclination angle of the lower surface of fluke gradually converged to zero.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124409534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance Evaluation of Displacement Measurement System with Marker and Fixed Vision Sensor on Port Structures","authors":"Jiyoung Min, Ryulri Kim, H. Jeon","doi":"10.20481/kscdp.2023.10.1.13","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.1.13","url":null,"abstract":"This study focused on the measurement of displacement on port structures with the combination of a marker and a vision sensor installed on the fixed location. The proposed algorithm optimizes the intrinsic parameters of the vision sensor using genetic algorithm and then measures the 6-DOF displacement automatically tracking feature points on the marker extracted through the image process. Experimental studies were carried out by using a general IP camera and a marker including 12 feature points. The distance between the camera and the marker was 10 m. Several types of displacements were induced with the precise motion stage, and the results showed that the measurement errors might be reasonable less than 3.5% in rotation and 4.0% in translation. This system was applied on the lock gate located in Incheon port, which corresponds to Type 1 facilities in Korea. The same camera was fixed at 24 m from the marker and the marker was moved by controlling the precise motion stage. The errors of measurements were less than 1 mm and 0.5 degrees, which were precise and accurate enough to evaluate the displacement in the field considering the present evaluation standard for drift, settlement, and slope on port facilities.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129345798","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Development of a typhoon wave overtopping prediction model based on an artificial neural network","authors":"Seung-woo Kim, H. Lee, Hyukjin Choi","doi":"10.20481/kscdp.2023.10.1.25","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.1.25","url":null,"abstract":"In this study, an artificial neural network (ANN) model for the typhoon wave overtopping was developed using the database by a numerical wave flume simulation. The developed ANN model is effective for saving calculation time largely. The accuracy of the model is also approached to over 95% of the numerical simulation. This accuracy was evaluated by the correlation coefficient and the root mean square error with the target data of the numerical simulation and output of the ANN model. This model quickly produces the mean wave overtopping rate, maximum wave run-up height, maximum wave overtopping depth and velocity at the middle point in the coastal road without high-fidelity numerical model and high-computing resources. It means that the typhoon warning system including the ANN models is powerful and useful rather than only the monitoring warning system currently in use.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132873172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Seung-Seop Jin, Jiyoung Min, Young-Taek Kim, Ryulri Kim
{"title":"Development of Online-learning based Adaptive Anomaly Detection Algorithm for Monitoring Data Analysis on Caisson Type Breakwater","authors":"Seung-Seop Jin, Jiyoung Min, Young-Taek Kim, Ryulri Kim","doi":"10.20481/kscdp.2023.10.1.1","DOIUrl":"https://doi.org/10.20481/kscdp.2023.10.1.1","url":null,"abstract":"Most port structures are massive and data measured on them sensitively changes to the surrounding environment including sea waves, tides, wind, and other operational conditions so it might be difficult to extract and long-term monitor their own features such as natural frequencies and mode shapes. To solve this problem, an anomaly detection algorithm with online learning was developed for the analysis of monitoring data on the port structures. For this, data were first measured on a 1/50 scaled model of caisson type breakwater through hydraulic model experiments, and the characteristics of data were investigated. Then an unsupervised algorithm was developed to online detect abnormal conditions caused by the drift, which can track the reconstruction error from the principal component analysis and the Euclidean distance between original and reconstructed signals. The experimental results showed that the proposed algorithm could be successfully applied to time-dependent dataset shifts with high accuracy and automatically calculate the threshold based on the adaptive model.","PeriodicalId":326564,"journal":{"name":"Korea Society of Coastal Disaster Prevention","volume":"325 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122632560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}