• Journal of Korea Water Resources Association
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• v.30 no.6
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• pp.743-751
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• 1997

A thorough literatural review of researches on the experimental prediction of scour depths caused by jets was carried out to find out a measure of scour prediction. A new experimental equation for predicting scour depths due to a vortical or an inclined jet was developed from five hundreds of experimental data which were carefully reviewed and adopted from the previous researches. The developed equation shows 0.941 statistical correlation coefficient. It was found that the parameters governing the scour depth were the size of bed material, flow rate through unit width of spillway, and head drop across structure. The predicted scour depth could be expressed as the deepest scouring depth below tail water surface with correlation coefficient ${\gamma}$ = 0.941.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.71-80
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• 2005

More than 100 bridges have been annually collapsed or seriously damaged by scouring in Korea. It is extremely hard to understand the complicated scour mechanism and estimate the scour depth with accuracy in fields, however since scouring is a very complex manifestation of sediment transport unable to describe with a simple mathematical tool. In order to obtain the reasonable solution to bridge scouring, therefore, the interdisciplinary co-operation is strongly recommended. In this study the special task force team for the scour problems around Incheon 2nd bridge piers is made, in which all kinds of scour oriented researches such as oceangraphic survey, hydraulic model test, numerical simulation, scour rate test, real-time scour monitoring, etc will be carried out. This paper provides this interdisciplinary procedure in details.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.713-718
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• 2005

A methodology is developed to evaluate the vulnerability of bridge piers to scour and to help establish effective disaster measures, taking into account the locality and scour characteristics in Korea. Based on the bearing capacity of bridge foundation-ground integrating system changed by scour, this methodology is able to prioritize bridge foundations reflecting on the geotechnical factors as well as hydraulic ones. The bridge foundation vulnerability to scour is categorized into 7 groups considering the concise information of the bridge foundation-ground integrating system. A case study of implementing this method which includes the analysis of the scour depth and evaluation, and categorizing the scour vulnerability of bridge foundation is presented.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.38-47
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• 2009

Scour means the erosion of bed material by flow change when a bridge is constructed in a stream. Scour is one of the critical factors of a bridge failure. There are several methods for the monitoring of scour near bridge foundations; Sounding rods, Magnetic sliding collar System, Sonar system, underwater camera system and so on. In general, Sonar system is preferred due to its convenience and good accuracy. In this study, the new scour monitoring system was developed using profiling sonar sensor. The new system can measure a line profile of a seabed and has small size due to the effectively designed data logger. The performance of the new scour monitoring system was evaluated at a bridge pier in tidal environment. The measured local scour depths were discussed with the result of the empirical formulas; CSU, Froehlich, Laursen and Neill.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.593-596
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• 2008

The scour phenomenon involves the erosive potential of flowing water and the relative ability of the soil to resist erosion. The scour phenomenon in cohesive soils is much different from that in non-cohesive soils. Granular soils resist erosion by their buoyant weight and the friction between the particles. The soil particles are dislodged individually from the bed under the action of the eroding fluid. Scour in cohesive soils is much slower and more dependent on soil properties than that in non-cohesive soils. Therefore the analysis models for estimating erosion characteristics of cohesive soils should consider not only flowing water but also the relative ability of the soil to resist erosion. In this study, erosion characteristics for the clay-silt mixed soil will be analyzed as a fundamental study for development of bridge scour analysis and design system considering scour resistance capacity of a soil. For this analysis, the relationship between scour characteristics and soil properties was evaluated through scour rate test with Kaolinite samples remolded using various loading and contents of silt.

• Proceedings of the Korea Water Resources Association Conference
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• 1987.07a
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• pp.87-87
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• 1987

Bridge piers are sometimes damaged by local scour. Although the problem of local scour around pier has been studied extensively, it has been difficult to estimate local scour deth quantitatively. This study is concerned with local scour around semicylindrical piers arranged in various types under the condition of clear water scour. Through dimensional analysis, it was found that scour depths were relative to Re, Fr, and Ns. In the case of semicylindrical piers, the variation of dimensionless scour depth with dimensionless time (effect of Ns, pier diameter and length, incidence angle) and the variation of scour depth with vortex intensity and resistance are investigated experimentally to obtain a formula. And forula for estimating the maximum depth of scour is obtained.

• Water for future
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• v.20 no.1
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• pp.41-47
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• 1987

Bridge piers are sometimes damaged by local scour. Although the problem of local scour around pier has been studied extensively, it has been difficult to estimate local scour depth quantitatively. This study is concerned with local scour around semicylindrical piers arranged in various types under the condition of clear water scour. Through dimensional analysis, it was found that scour depths were relative to Re, Fr, and Ns. In the case of semicylindrical piers, the variation of dimensionless scour depth with dimensionless time (effect of Ns, pier diameter and length, incidence angle) and the variation of scour depth with vortex intensity and resistance are investigated experimentally to obtain a formula. And formula for estimating the maximum depth of scour is obtained.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.374-382
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• 2021

The scour risk assessment was conducted for ultimate limit state of newly developed penta pod suction bucket support structures for a 5.5 MW offshore wind turbine. The hazard was found by using an empirical formula for scour depth suitable for considering marine environmental conditions such as significant wave height, significant wave period, and current velocity. The scour fragility curve was calculated by using allowable bearing capacity criteria of suction foundation. The scour risk was assessed by combining the scour hazard and the scour fragility.

• Journal of Korea Water Resources Association
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• v.47 no.10
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• pp.907-919
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• 2014

This study presents scour processes and its characteristics around the pile groups using the large eddy simulation (LES) coupled with sediment transport and morphodynamic models. The scour and deposition around pile groups were significantly influenced by the pile interval. In case the non-dimensional pile interval was less than 3.75, the local scours as well as the contraction scour were observed around the pile group. On the other hand, in case the non-dimensional pile interval was more than 3.75, the contraction scour disappeared and only local scours were developed at individual piles. Change in the scour depth at piles located in the upstream was similar with the case of single pile, but the scour depth around piles located in the downstream was lower and showed a significantly different tendency due to the presence of piles in the upstream. The non-dimensional maximum scour depth around the pile group decreased as the pile interval increased.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.117-123
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• 2009

This study is to investigate the characteristics of scour around pipeline in current and hydraulic model tests were performed. All the model test are 45 cases, which were conducted with velocities of 0.2 m/s to 0.5 m/s and pipe diameters of 45, 60, 90 mm. The developments of scour around pipeline were observed and equilibrium scour depths were recorded due to variation of pipe diameter and current velocity. According to the results, the equilibrium scour depth was proportional to current velocity and pipe diameter. The effect of diameter of pipeline on the equilibrium scour depth was bigger than current velocity. The correlations of relative scour depth and dimensionless number such as a Reynolds number, Shields number, and Froude number were analyzed. The Froude number and the relative scour depth had a high correlation of 0.900.