• Title/Summary/Keyword: 부유토사

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Simulation of Dredging Turbidity Flow Using 2-D Numerical Model (2차원 수치모형을 이용한 준설현장 탁류 모의)

  • Jeong, Young-Won;Kim, Young-Do;Park, Jae-Hyeon;Lee, Man-Soo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2008.05a
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    • pp.1418-1423
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    • 2008
  • 연안이나 하천 등에서 공사 시 준설작업으로 인해 많은 양의 부유토사가 발생되며 발생된 부유 토사의 이송 확산은 수환경에 변화를 초래한다. 따라서 준설작업에 있어 부유토사물의 이송 확산 범위를 사전에 예측하고 대비책을 세우는 것이 중요하다. 부유토사는 준설작업 시 Cutter Head가 해저면에 닿는 순간부터 작동을 멈출 때까지 계속하여 발생하며, 이러한 과정들이 반복되면서 많은 양의 토사가 발생한다. 이렇게 발생한 부유토사는 수체흐름에 따라 움직이는데 조류가 있는 연안에서는 시간에 따라 흐름이 달라지게 된다. 본 연구에서는 2차원 수치모형인 RMA2, RMA4를 이용하여 부유토사의 확산과정을 모의하고 준설현장에서 부유토사흐름을 실측하여 비교하였다.

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The Movement Characteristics of Suspended Solid(SS) in Harbor Construction(II) - The Landfill Construction and The Grab Dredging Construction (항만공사시 부유토사의 거동 특성에 관한 연구(II) - 매립 및 준설공사시 -)

  • Lee Ji Wang;Maeng Jun Ho;Cho Kwang Woo;Yang Gwon Weol;Kim Young Seup
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.6 no.2
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    • pp.46-53
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    • 2003
  • In order to analyze the movement characteristics of suspended solid(SS) in harbor construction, we investigate the generation and movement processes of the SS for the landfill construction by direct casting method and the grab dredging construction which is the most frequent process in harbor construction. We find that the SS is generated into a very high concentration right after the direct casting of landfill soil and continued up to 60 minutes in the landfill construction using the direct casting method with dredged materials by a ship of 700-tonnage. In the grab dredging construction, the SS is generated in a high density of concentration near at its source regardless of water depth, formed belt and diffused up to 700m along the trajectory of tidal current. Based on the result of the present study, it is recommended for the mitigation of SS generation that the silt protector be deployed near at construction site close enough to block the diffusion of SS and the body length of silt protector be long enough to mitigate the SS diffusion in the bottom layer.

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The Effects of Suspended Solids on the Mortality and the Glycogen Content of Abalone, Haliotis discus hannai (참전복, Haliotis discus hannai의 폐사 및 글리코겐 함량에 미치는 부유토사의 영향)

  • Lee, Kyoung-Seon
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.14 no.3
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    • pp.183-187
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    • 2008
  • Elevated concentrations of suspended solids in the marine enrironment caused by coastal developments have threatened to the marine ecosystem. Effects of suspended solids on the mortality and the modifications of glycogen levels of abalone, Haliotis discus hannai were studied. Abalone were exposed to suspended solids with concentrations of 0 (control), 1,000, 1,500 and 2,000 mg/ L for 96h. These suspended solids had no effect on the mortality of abalone. Significant decreases in the glycogen content of soft tissues were observed over 1,500 mg/ L concentration of suspended solids. These results suggested that abalone could tolerate a high level of suspended solids. However, it is necessary to observe further the long term effects of suspended solids on the physiological responses of abalone.

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The Movement Characteristics of Suspended Solid(SS) in Harbor Construction(I) - In a Riprap Work - (항만공사시 부유토사의 거동 특성에 관한 연구(I) -사석공사시-)

  • Lee Ji Wang;Maeng Jun Ho;Cho Kwang Woo;Yang Gwon Weol;Kim Young Seup
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.6 no.2
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    • pp.38-45
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    • 2003
  • This paper intends to analyze the movement characteristics of the suspended solid(SS) generated in a riprap work which is the most widespread process in harbor construction. The generation and movement behaviors of SS are investigated when 1) basic ripraps (0.001~0.03㎥) are cast for breakwater construction, 2) ripraps are loaded on carrier for riprap casting in the sea-wall construction of dredged material pocket, and 3) ripraps for inner filling are cast. The result of the present study shows that the SS generation is considerable when basic ripraps are cast for breakwater construction and the SS diffusion reaches up to 500m in high tide period. When ripraps are loaded on carrier, the SS is generated by the ripraps running down into sea from carrier, thereby showing a high concentration of SS in the vicinity of carrier. In the surface layer, SS distribution is confined in the vicinity of the carrier due to the prompt sinking of the SS. However the SS in the bottom layer is diffused approximately up to loom and then the SS concentration reaches to the background one. In the riprap (less than 0.03㎥) casting for inner filling using pork crane, SS is diffused approximately up to 300m in the surface layer and more than 300m in the bottom layer. It is quite interesting that the movement of the SS generated in harbor construction is mainly controlled by wind drift in the surface layer and tidal current in the bottom layer, and also the diffusion range of SS in the bottom layer is much larger than that in the surface layer.

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A Proposed Guidance on the Installation and Maintenance of Silt Curtains (오탁방지막 설치ㆍ유지관리 지침(안))

  • 진재율;송원오;맹준호;오영민;채장원;안희도;박진순;오재경
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 2003.08a
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    • pp.185-193
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    • 2003
  • 준설, 매립 등의 해상공사가 해양환경에 영향을 미치는 주 요인은 공사중 발생하는 부유토사이다. 이러한 부유토사는 주변 해역으로 확산되어 여러 방식으로 해양생태계에 피해를 유발할 수 있으며, 발생 가능한 피해의 범위와 정도는 부유토사 발생율과 해저 죄적물 입도분포 및 주변 유속에 따라 결정된다. (중략)

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Comparison of Silt Protector Design Between Korea and Japan (한일간 오탁방지막 설계 비교)

  • 오영민;송원오
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.15 no.1
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    • pp.66-70
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    • 2003
  • Harbor construction works such as dredging, reclamation, riprap dumping and so on generate suspended sediment to affect ocean environment negatively so silt protector is widely used to keep construction site from deteriorating at the moment. This study has a purpose to improve our design techniques by comparing the design procedures of the silt protector between Korea and Japan.

Estimation of the Range of the Suspended Solid from the Nakdong River using Satellite Imageries and Numerical Model (위성영상 및 수치모델을 이용한 낙동강유출 부유토사 확산범위 추정)

  • Hwang, Jae-Dong;Kang, Yong Q.;Suh, Yong-Sang;Cho, Kyu Dae;Park, Sung Eun;Jang, Lee-Hyun;Lee, Na Kyung
    • Journal of the Korean Association of Geographic Information Studies
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    • v.5 no.2
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    • pp.25-33
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    • 2002
  • We were trying to understand indirectly the range of the discharge from the Nakdong with the dispersion of suspended solid(SS) related to the amount of discharge from river in this study. The range of dispersion of SS from the Nakdong was estimated using satellite remote sensing and numerical modeling. The stream field with two dimensional and numerical model using the condition of integrated depth was calculated. According to the results, the streamline flowed from Busan to the Jinhae Bay and Geojae Island. at the flood. The situation at the ebb was totally changed. The streamline flowed out Busan from the Bay. The velocity in offshore was faster than one at coastal water of the Nackdong. Residual current which was averaged during 12hours dominantly appeared the dominant direction from the southwestern part of the Nackdong to the northeastern part of it. The eastward current appeared at the eastern coast of Gaduck Is. Base on the results of the velocity field, the quantifying of the dispersion of SS was estimated by the method of numerical tracer related to the Lagrangian method. The significant range of the dispersion of the SS from the Nackdong was from the eastern coast of Gaduck Is, to the coastal areas of Busan, Korea. The estimated range of the dispersion of the SS using the SeaWiFS and Landsat satellite data was similar to the estimated results using the numerical model.

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