Journal of Korea Water Resources Association (한국수자원학회논문집)

Korea Water Resources Association (한국수자원학회)
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Effects of bed material on scouring under high-velocity flow conditions

고유속 흐름에서 하상재료에 따른 세굴 영향 연구

  • 김광수 (인제대학교 환경공학과) ;
  • 정동규 (인제대학교 환경공학과) ;
  • 김영도 (인제대학교 환경공학과(낙동강유역환경연구센터)) ;
  • 박용성 (던디대학교 토목공학과)
  • Received : 2018.11.16
  • Accepted : 2018.12.27
  • Published : 2019.02.28
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Abstract

In this study, the degree of scouring according to the bed material according to the flow rate and the relationship between the flow velocity and the bed scouring were investigated in order to examine the operability of the revetment and embankment. The materials used in the experiment were sand and loess as materials used in the embankment. We measured the scouring of the material according to the change of the flow velocity by using the indoor high flow velocity experiment device and verified the flow rate. In this way, The purpose of this study was to compare and analyze changes in material before and after scouring, and compare basal scouring evaluation by bed material with high flow velocity. In case of sand, the cohesive force is very weak, so more than 40% of the material is lost even at less than 1.0 m/s. In the case of loess, less than 6% of the bed material is lost at more than 2 m/s. The reason why the material was lost was that the cohesion was so strong that the material was dried after the compaction and cracked. As a result, the material was lost from the part where the dry crack occurred. In this study, the composition and loss of bed materials were evaluated.

본 연구는 하상재료의 종류와 유속에 따른 세굴변화에 대한 연구를 진행하였고, 유속, 구성방법 및 재료와 세굴에 대한 상관관계를 정의하여 호안 및 제방의 운용성을 검토하고자 실험을 통한 연구를 진행하였다. 본 연구의 실험에 사용된 재료는 제방에 사용되고 있는 재료로 모래, 황토를 이용하였다. 실험실규모 고속수로에서 다양한 계측장비들을 이용하여 유속의 변화에 따른 재료의 세굴을 측정하였다. 이를 통해 세굴 전 후의 재료변화를 수치적으로 분석하였다. 고유속흐름에서 하상재료에 따라 세굴의 정도를 비교 평가하여 안정성에 대한 연구도 진행하였다. 실험 결과 모래의 경우 응집력이 매우 약하여 1.0 m/s 이하에서도 40% 이상의 재료가 유실이 되고 황토의 경우 모래보다 유속이 빠른 2 m/s 이상에서도 6% 이하의 재료가 유실이 되었다. 재료가 유실된 이유중 하나는 강한 응집력으로 건조균열이 발생하여 세굴에 취약한 결과를 보였다. 본 연구에서는 이러한 건조균열의 발생부터 재료가 유실되는 현상을 제거하는 방법부터 재료에 대한 구성과 유실정도를 평가 하였다.

Keywords

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Fig. 1. Schematic diagram of the high-speed open channel

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Fig. 2. Real-time measuring device

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Fig. 3. Experimental material

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Fig. 4. Rectangular port (12*16*16 cm)

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Fig. 5. Meterial three sroties compaction

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Fig. 6. Comparison of re-stomping of the meterial before and after the dessication crack

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Fig. 7. Scour measurement point

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Fig. 8. Degree of scouring according to the change of flow rate according to material

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Fig. 9. Materials for different types of materials loss

Table 1. Experimental conditions

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Table 2. Experiment scouring result

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