• Title/Summary/Keyword: berm

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Comparision of Overtopping Performance and Prediction Models for Rubble Mound Breakwaters Armoured Tetrapod (테트라포드로 피복된 사석경사제에서 월파 성능 및 예측모형의 비교)

  • Kim, In-Chul
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.22 no.6
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    • pp.397-404
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    • 2010
  • Laboratory tests of wave overtopping rates for a rubble mound breakwaters armoured Tetrapod were carried out, with varying design waves, crest berm widths and crest freeboards. The objective of this study is to investigate overtopping performance and to examine the characteristics of the widely used overtopping prediction models through the results of laboratory tests. Laboratory tests show that structure slope and wave periods have a considerable influence on overtopping rates, but the difference of overtopping rates related to crest berm widths is slight. Owen(1980)'s prediction considerably overestimates compared to the measured valued. Prediction of Van der Meer et al.(1998) underestimates only for steep slope($cot{\alpha}$=1.5). Besley(1999)'s and Pedersen(1996)'s predictions have a relatively good agreement with the measured results for slopes with a broader crest berm width. In general, best agreement between measured and predicted overtopping rates is observed using modified Pedersen(1996)'s formula for all test conditions.

Analysis of Quarrying and Restoration Characteristics on Quarry in Korea (국내 토석사업장의 토석채취 및 복구특성 분석)

  • Park, Jae-Hyeon;Kim, Ki-Dae;Kang, Min-Jeng
    • Journal of Korean Society of Forest Science
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    • v.105 no.2
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    • pp.223-230
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    • 2016
  • This study was carried out to investigate the quarrying and restoration characteristics on quarry in Korea. We researched quarrying and restoration status, analyzed the relationship between restoration area and permitted period, permitted area, quarrying volume, pit slope width, height, and berm width from 55 quarry sites. Most of the quarries were located in the following conditions : mixed forest, average altitude of less than 300 m, average mountain slope of $61^{\circ}$<, hillside, granite and landslide hazard class. Major quarrying characteristics were permitted period of 6~10 years, permitted area of less than 10 ha, quarrying volume of less than $1,000,000m^3$, a stone type of aggregate, a quarrying type of terrace, pit slope of $61^{\circ}$< Most quarries were restored by themselves, and the main restoration type was slope greening. Also, area ratio of flatland, pit slope, and berm was 54.9:39.6:5.5. Ccorrelation analysis showed that quarrying area was positively correlate with quarrying volume (${\alpha}=0.01$), permitted area, pit width, and pit height (a=0.05).

Analysis of Beach Gravels, the Weaver Peninsula, King George Island, Antarctica (남극 킹 죠지섬의 위버 반도 해빈자갈에 관한 연구)

  • 박용안;최문영;고영이
    • The Korean Journal of Quaternary Research
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    • v.5 no.1
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    • pp.47-61
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    • 1991
  • Textural analysis of gravels of raised beach (old beach) in the Weaver Peninsula, King George Island, Antarctica has been carried out as a first part study among 20 other sites surveyed in the Weaver Peninsula and Barton Peninsula, King George Island. The raised beach described as WP-5 in this paper is 3.95 m higher than the present beach in elevation. And it is described as old beach. The beach shows typical subenvironment, that is, beach berm and beach face. Mean size, mean roundness and mean sphericity of gravels from beach berm are -4.10ø, 0.44 and 0.66 respectively. However, mean size, mean roundness and mean sphericity from beach face are -4.23ø, 0.41 and 0.67 respectively. In particular, it seems to be worthy to note the differences of textural parameters between Antarctic glacio-marine beach gravels and temperate and normal marine beach gravels. Under such conception the present study wishes to show only textural parameters, i.e., size, roundness, sphericity and shape obtained from the analysis of Antarctic glacio-marine beach gravels.

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A Study on the Peak Runoff Reduction Effect of Seolleung·Jeongneung Zone by Applying LID(Low Impact Development) System based on the Landscape Architectural Technology (조경기술기반 LID 시스템 적용을 통한 선릉·정릉 권역의 첨두유출량 분석)

  • Kim, Tae-Han;Choi, Jong-Hee
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.35 no.4
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    • pp.126-133
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    • 2017
  • This study analyzed hydrological changes of stormwater runoff of Seolleung Jeongneung zone according to the application of LID system based on landscape Architectural technology. The results are as follows. First, when flooding occurred in Gwanghwamun in July 27, 2011, the maximum instantaneous rainfall amount was 183 mm/hr recorded at 10:00 on 27th for 10 minutes, and it was confirmed that rainfall intensity more than three times as high as the maximum rainfall of 57.5 mm/hr. Second, it is possible to control peak flow rate in the case of 1,500mm of soil thickness, so that it is possible to improve the vulnerability of flood damage in Seolleung and Jeongneung zone when applying the LID system. Third, in the berm height scenario, peak flow rate control was not controled in all depth level models, but the first stormwater runoff was delayed by 4 hours and 10 minutes compared to the soil thickness scenario. It was interpreted as a relatively important indicator the soil thickness for the initial stromwater runoff reduction and the berm height for the peak runoff. Through this, the systematic adaptation of landscape-friendly ecological factors within the cultural property protection zone could theoretically confirm the effects of flood disaster prevention.