- 期刊
連續性沉砂池囚砂率之研究
Trap Efficiency in a Series of Small Settling Basins
摘要
目前常見之沉砂池囚砂率的經驗式，均假設沉砂池中的水流爲水平流況，其邊壁的擾動對其影響可忽略，在大型的沉砂池如水庫取水口，或在發電廠等設計之沉砂池或許可以達到其水平流況的條件。然而一般山坡地開發或高爾夫球場之沉砂池其水流迴流區所佔的比例則不可忽略，至於在農地之簡易沉砂池中的流況甚至不可能發生有水平流的情形。所以若使用以往的經驗式來估計農地簡易沉砂池的囚砂率並不十分恰當。本文利用前人之究的成果，並對於連續構築之沉砂池之囚砂率做探討，進而推求一具有迴流現象之連續沉砂池所適用之公式。由於山坡地開發時常會利用現地之地形或原有之排水設施建造沉砂池設備，如利用原有之排水渠道，在渠道中設置柵欄使得開發時所產的泥砂淤積於臨時之沉砂池內。本文乃利用所得迴流區沉砂池囚砂率之經驗式，推求利用即有渠道內建構連續之柵欄所形成之連續沉砂池的囚砂率，由實驗分析，連續沉砂池在囚砂率方面確較單一沉砂池爲佳。
並列摘要
Regular flow conditions were usually assumed in the empirical trap efficiency formulas of settling basins. This assumption can be accepted in large settling basins t for example the inlet of a reservoir, because the circulation zone that is produced by the walls can be ignored in large settling basins. However, this influence is very important in small hillslope settling basins, such as detention ponds or agricultural drainage works. Construction activities are a major cause of soil erosion because huge areas are stripped of vegetation and worked over at the same time. Although stortage of land often precludes the use land to build a large of settling basins in Taiwan, building a series of small settling basins in the original drainage systems is feasible. 'This basin can be temporary and filled in after urbanization. The purpose of this research is to derive a formula to estimate the effective trapping capacity of a series of small settling basins. In this article, flume tests are performed and the trap efficiency formula is modified. From the result, the trap efficiency of a series of small settling basins determined to be significanthy better than that of one huge settling basin.