KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Analysis of Roughness Coefficient in Gravel-bed Rivers

자갈하천의 조도계수 특성 분석

  • 이찬주 (한국건설기술연구원 하천해안항만연구실) ;
  • 김용전 (한국건설기술연구원 하천해안항만연구실) ;
  • 김지성 (한국건설기술연구원 하천해안항만연구실) ;
  • 김원 (한국건설기술연구원 하천해안항만연구실)
  • Received : 2009.03.30
  • Accepted : 2010.02.19
  • Published : 2010.04.30
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Abstract

The purpose of this study is to analyse characteristics of roughness coefficient based on bed-material size of the gravel-bed rivers using field data obtained from nine domestic rivers. Roughness coefficient is calculated using Manning's equation. Roughness coefficient decreases with increasing discharge, but above a certain discharge, it tends to be constant. Similarly, roughness coefficient shows reverse relationship with relative smoothness (R/D). The regression equation adopting theoretically derived value of 2.03 as log coefficient indicates close similarity with the previous equation proposed by Limerinos (1970). Roughness coefficient values converged above certain discharges lie in the range from 0.024 to 0.045. From them, empirical equations based only on bed-material size are derived and compared with those suggested by the previous studies.

본 연구는 국내 9개 하천에서 실측한 자료를 사용하여 하상재료의 입경에 기초한 자갈하천의 조도계수 특성을 분석하는데 그 목적이 있다. 조도계수는 Manning 식을 역산하여 산정하였다. 산정된 조도계수는 유량에 따라 대체로 감소하였으며, 일정한 유량 이상에서는 수렴하는 특성을 나타냈다. 마찬가지로, 상대수심(R/D)이 증가함에 따라 조도계수는 감소하는 경향을 보여주었으며, 실측 자료를 이용하여 적합식을 구한 결과 Limerinos(1970) 식과 매우 유사한 결과를 보여주었다. 일정한 유량 이상에서 수렴된 조도계수값은 0.024~0.045의 범위에 있었으며, 이를 기초로 하상재료만을 고려한 조도계수 산정식을 도출하고 기존의 식과 비교하였다.

Keywords

References

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