• Title/Summary/Keyword: Scour

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A Study of Artificial Reef Subsidence in Unsteady Flow-Wave Field (비정상 흐름-파랑 공존장의 인공어초 침하특성에 관한 연구)

  • Yun, Sang Jun;Kim, Heon Tae
    • Journal of Ocean Engineering and Technology
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    • v.15 no.3
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    • pp.29-29
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    • 2001
  • The experimental studies for the artificial reef (AFR) subsidence characteristics in the unsteady flow field and in the unsteady flow-wave field were carried out. The difference of scour/subsidence characteristics between in the steady flow field and in the unsteady flow field wad discussed and also the long-term subsidence characteristics in the unsteady flow field were investigated. AFR subsidence characteristics was discussed with Keulegan - Carpenter number(KC), Reynolds number (Re),. Shields number (Sn) and dimensionless time (t/Tt). And the difference of subsidence characteristics between in the unsteady flow and in the unsteady flow-wave field was discussed.

Design of Ship Thruster and Seabed Scouring due to Effects of Water Velocity

  • Choi, Byoung-Yeol;Lee, Sang-Gil
    • Journal of Advanced Research in Ocean Engineering
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    • v.3 no.3
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    • pp.102-111
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    • 2017
  • This study considered the effects on the seabed of a harbor and quay wall from ship maneuvers in relation to the thruster jet flow and initial velocity. This study also included the engine capacity, RPM, and diameter and pitch of a ship's thruster for a required speed. The impact of a scour hole on the environment of a quay wall was investigated. Based on these results, a risk based analysis was conducted to evaluate different strategies and their consequences. There has been an increase in the loads on the bottom of a harbor during ship maneuvering. This increase is caused by the propeller loads of mooring and unmooring vessels. This indicates a greater number of arrivals and departures of vessels with larger drafts, larger thruster diameters, and larger available thruster power capacities. Another important cause could be an increase in the maneuverability of vessels from the use of bow thrusters. The increasing loads, which cause a higher jet flow above the bottom, can lead to undesirable scour holes.

Development of Computer Program for Bridge Pier Scour Considering Accumulative Effect (축적 효과를 고려한 교각세굴 해석 프로그램 개발)

  • ;Briaud, Jean-Louis
    • Journal of the Korean Geotechnical Society
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    • v.17 no.3
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    • pp.5-13
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    • 2001
  • 세립토에서의 세굴깊이의 발달은 일반적으로 조립토에서보다는 아주 천천히 진행된다. 조립토를 위해 개발된 방법을 시간효과와 무관하게 세립토에 적용한다면 세굴깊이가 과대하게 평가된다. SRICOS 방법은 점성토 또는 연암에 설치된 교각의 국부세굴깊이의 변화를 예측하기 위해 개발되었으며, 교량현장에서 채취한 흙에 대한 실험과 SRICOS 프로그램의 수행을 병행함으로써 적용된다. 본 논문에서는 SRICOS 방법을 간단히 설명한 후 프로그램의 세부적인 내용을 기술한다. 또한 이 프로그램을 이용하여 세굴에 미치는 각 매개변수의 영향을 평가하기 위해 실시한 매개변수 해석의 결과가 포함된다.

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Study on Scour Countermeasures during Revetment Construction in Silty Sand Soil Layers (실트샌드 지반상 사석호안 축조시 원지반의 세굴대책에 관한 연구)

  • Yang, Tae-Seon;Ahn, Jung-Seon;Cho, Young-Gu;Ji, Tae-Gyun;Kim, Hee-Dong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.322-329
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    • 2006
  • On the way of construction in harbor area, scourin problems took place slowly failure of embankment in the beginning of construction in sites. For studying on the scouring properties during revetment construction in silty sand soil layers, this paper is carried out on lessons of case studies of numerical seepage analysis, scouring countermeasures in dredged landfill area.

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A Study on Silt Transport of Seabed Around Incheon Harbor (인천항 주변 silt 이동에 관한 연구)

  • Baek, Seung-Hwa
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.3
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    • pp.133-142
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    • 2010
  • We calculated using siltation model to know the influnce of the tidal current, the tidal level, the sediment transport of seabed around sea area due to the construction of the Song do New city. We calculated the tidal current and based on this we estimated scour, sedimentation using the advection-diffusion equation and accessed the sediment transport of seabed before and after the construction of the New city. Sedimentation was increased in the east coast of Young jong Do, and Scour was increased according to the direction from the front route of north harbor to Ho do. Tidal level was increased overall.

Measurements of Erosion Rate in Fine-Grained Soils (세립토의 침식율 측정)

  • 곽기석;정문경;정하익;우제윤;조삼덕
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.337-342
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    • 2002
  • A new apparatus called the EFA (Erosion Function Apparatus) has been built and tested to measure the erodibility of fine-grained soils. The EFA is a simple test to predict the erosion rate of fine-grained soils along with the corresponding velocity and shear stress. In addition, it is advantageous in predicting the scour rate for actual soil samples from bridge sites. The plot of erosion rate versus shear stress is the result of an EFA test. It Indicates the critical shear stress at which erosion starts and the rate of erosion beyond that shear stress. In order to measure the erodibilities of various soils, 14 Shelby Tube soil samples are collected from the actual bridge sites and tested using the EFA. The results of the EFA tests which are the relationships between erosion rates and shear stresses are presented in this paper and research continues to develop the correlation between the erosion function and the soil properties.

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