堆砂籬定砂功效之探討

本研究旨在探討主、翼籬之夾角與長度對堆砂籬定砂功效之影響，以及苑裡濱海地區飛砂量之推估式；據此本研究採用現地及風洞試驗兩種方法，現地試驗於苗栗縣苑裡鎮濱海地區勘選適宜地點，架設多層風速計、BSNE垂直式集砂器及Davis氣象儀器等進行觀測；為進一步瞭解主、翼籬之夾角與長度對堆砂籬定砂功效之影響及獲得整體飛砂量推估式，再進行風洞試驗，以彌補現地試驗之不足。經由現地試驗結果得知，苑裡試區砂粒之中值粒徑（d50）為0.19～0.27 mm，密度（σ）為2.55～2.7 g/cm^3，含水率（ω）為1.1～5.1%；上述參數與飛砂量均呈負相關，而與風速（U0.25）呈正相關，如飛砂量推估式所示：��=14.4858×(��^2 0.25 / ��×��50×��/��×��)−0.1208×��50×��0.25×��經分析堆砂籬於東北季風期間其定砂功效為87.62 %，平均每平方公尺土地面積之堆砂量為0.871 m^3；再者，由風洞試驗結果得知，主、翼籬夾角對堆砂功效之高低，依序為22.5°＞45°＞90°＞0°；又翼籬長度為3倍籬高以上時，則可有效提升堆砂離之定砂功效。

關鍵字

堆砂籬；風洞試驗；飛砂量

並列摘要

The main purpose of this research is to discuss how the angle between main and wing hedge, and the length of wing hedge affect the piling effect of sand-fixed hedge, and to discuss the function of the aeolian sands along the coastlands in Yuanli. Thus, this research adopted the following two methods, field experiments and wind tunnel experiments. The field experiments set multi-layer anemometer, BSNE sand collector and the instruments of Davis observation for survey at the Yuanli coast of Miaoli. For further understanding of how the angle between main and wing hedge, and the length of wing hedge affect the piling effect of sand-fixed hedge and to obtain the function of the aeolian sands, wind tunnel experiments are to complete field experiments.According to the field experiments result, the distribution of medium diameter (d50) is 0.19~0.27mm, the density (σ) is 2.55~2.7 g/cm^3 , the water content (ω) is 1.1~5.1%. The parameters above are in a negative relationship with the amount of aeolian sands, but in a positive relationship with the wind speed (U0.25). The function of the aeolian sands is as follow:The Symbol is abbreviatedAnalysis showed that the piling effect of sand-fixed hedge in winter is 87.62%, the average unit area fixed aeolian sands for 0.871 m^3; furthermore, in result of wind tunnel experiments, the order of the angle between main and wing hedge caused on the piling effect is 22.5°＞45°＞90°＞0°, and when the wing hedge is three times taller, the piling effect of sand-fixed hedge will be efficiently lifted.

並列關鍵字

Sand-fixed hedge ； Wind tunnel experiment ； Wind blown sand

國際替代計量

堆砂籬定砂功效之探討

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