• Title/Summary/Keyword: permissible tractive force

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A Suggestion of Formulae to Calculate Sectional Tractive Force on the Slope of Cohesive River Bank and its Application (점착성 제방사면의 구간별 소류력 산정식 제안 및 적용)

  • Han, Man-Shin;Choi, Gye-Woon
    • Journal of Korea Water Resources Association
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    • v.45 no.6
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    • pp.583-596
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    • 2012
  • The revetment is a installed structure on the slope of river bank to protect against flowing. Through the design standards of domestic and overseas, the maximum tractive force is calculated and applied to the average concept on the slope of river bank. In the case of calculating the method of permissible tractive force on the slope of river bank, there is a need to consider soil sliding. In this study, suggested the tractive force formulae by section of adhesion that have 0 < ${\Phi}$ < $90^{\circ}$ slope of river bank and installed an open channel of length of 20 m and 2 m wide for calculating permissible tractive force and hydraulic model experimented with changing discharge. According to the results, the calculated permissible tractive force of section on the slope is the largest due to the significant effects of surface roughness of different revetment materials. In addition, the permissible tractive force increased in the presence of vegetation but has no the effect by vegetation density.

Stability Analysis of Low Flow Revetments on External Forces (저수호안에 작용하는 외력에 의한 안정성분석)

  • Kim, Chul;Park, Nam-Hee;Kim, Dae-Young;Kim, Yun-Hwan
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.5
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    • pp.147-153
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    • 2008
  • Tractive forces by flowing water and ship generated waves are items that affect the stability of the low flow revetments among various external forces exerting on those revetments. Bank revetment stability by these external forces is analysed in this study. The study area is the section of the test construction area changing the artificial revetments to ecological revetments in Han river. Tractive forces are computed using the calculated flow velocity using RMA-2 model. The stability is analyzed comparing the calculated tractive forces with permissible tractive forces of the revetments in the study area. The calculated tractive forces at section number 93 is higher than permissible tractive forces in that section, so the section is estimated hydraulically unstable. The calculated tractive forces for the storm of 10th August 2007 are small compared to the permissible tractive forces in all sections. The sections are considered to be hydraulically stable, but have been eroded in some parts. The reason for the erosion is considered to have insufficient time for the plants taking root, and be exerted composite forces such as forces by ship generated waves. Ship generated waves by the excursion boats and small boats called river taxi was calculated. Wave forces by these calculated waves are computed and compared with the supporting forces of the revetment material. The external forces exerted by the ships in Han River on the revetments is very little compared with the permissible supporting forces of the revetments, so the revetments are estimated hydraulically stable. But considering the composite forces are exerted simultaneously, the stability consideration should include these composite forces.

Application of Fiber Stone for Bridge Pier Scour Protection (교각 세굴방지를 위한 섬유돌망태의 적용성)

  • Kim, Seong-Won
    • Proceedings of the Korea Water Resources Association Conference
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    • 2011.05a
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    • pp.337-340
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    • 2011
  • In this study, qualitative and quantitative evaluations are performed using the hydraulic analysis of fiber stone for bridge pier scour protection. We can consider that the effective scour protection should be suggested from the side of hydraulic stability, structure stability, and permissible tractive force. The perfect verification, however, on the fiber stone for bridge pier scour protection is not sufficient because of short literatures and experiments on the field study. The continuous research, therefore, will be needed to establish reliable verification using literatures investigation and the various experiments on the fiber stone for bridge pier scour protection.

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A Monitoring and Data Analysis for Close-to-Nature Pilot Creeks (자연형 소하천 모니터링 시범사업 결과 분석)

  • Yi, Sang-Kuk;Chung, Jae-Hak;Lee, Ho-Yul;Lee, Jong-Seol
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.751-754
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    • 2008
  • Recently according to increasing of damage in creeks, it has been needed to develop a close-to-nature creek improvement technique considering flood safety as well as the functions of ecosystem and scenery preservation. In this study, the monitoring on creeks in seven provinces was accomplished to develop the technique applicable to domestic creeks between 2002 and 2007. Although the riparian ecosystem was disturbed, after just finishing the improvement on pilot creeks, the result of monitoring showed that restoration rates of creeks were satisfactory by constructing close-to-nature creek revetments. However it is hard to analyze on restoration and permissible tractive force of each revetments constructed in most creeks, because of insufficient monitoring data. Therefore the feasible study on the close-to-nature creek revetments should be performed in the near future through continuous monitoring on creeks.

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