- 作者: 蘇重光
- 作者服務機構: 私立逢甲大學水利工程學系
- 中文摘要: 根據雅林(Yalin)將推移質運移率以雙乘數表示之概念,一種嶄新推移質採樣器之首要部份已在實驗室發展成功。本採樣器採台秤形式置於石質河床,可用來測量滑落於河床單位面積上推移質之重量。 本採樣器以應變計為重量感測元件,總共十六片應變計分別黏貼於四根中空方柱體表面。應變計之輸出值與測定物真實重量間之線性關係非常良好。為探討靜水中所率定之關係可否應用於流水之情況,乃以採樣器之原型在大型流槽中進行水理試驗,結果發現因亂流之變動速度以及推移質運移方式而引起之測器基準點之偏差,其量甚微,實可忽略之。換言之,即靜水中之率定關係一式足矣。此外,並在流槽中模擬實際河川推移質之運動,共分滾動、平移和跳躍諸方式個別探討,發現測器反應迅速,感測之分辨力佳,可輕易獲得推移質重量歷線,足能應付野外現場洪水來臨時之變化。
- 英文摘要: Based upon the concept conceived by Yalin that the rate of bed load transport be expressed as theproduct of two multipliers, the first part of an entirely new type of bed load sampler has been successfullydeveloped. The sampler had the form of a platform scale that when flush-mounted in the gravel-bed stream,could measure the weight of the bed load moving over the surface of the stream bed. It was free from mostdefects found in other existing samplers. Strain gages were used as the weight-sensing elements of the sampler. They totaled up to 16, whichadhered evenly to the faces of four supporting coulumns. The linear relationship between the output signaland the weight of the measurand was excellent. In order to decide whether the calibration equation foundunder hydrostatic conditions also holds under hydrodynamic ones, a number of hydraulic tests were con-ducted in a laboratory flume with the prototype. It was found that the zero shift of the output signal dueto fluctuation velocity of the turbulent flow and different modes of bed load movement was quite negligi-ble, and the measurement was indeed accurate. It was also noted that the response of the sampler was fastand its resolution of measurement very high. The sampler would be able to cope with any abrupt change inthe field situations during a flood event.
- 中文關鍵字: bed load sampler; bed load; sediment transport; gmvel-bed streams; total load
- 英文關鍵字: --