裸土與植生狀況下土壤沖刷之試驗研究

A flume test of erosion in the bare soil and planted channels

邱俊文(Jyun-Wun Ciou)

指導教授 ： 林鎮洋

國立臺北科技大學/工程學院/土木與防災研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00618

摘要

近年來有許多關於河溪整治生態工法的相關研究，然而大多數的研究係針對工程的安全性或植生之綠覆成效做分析，對於裸露的河床、邊坡，以及植被覆蓋的河床、護岸，面對不同流速沖刷下的耐受度差異為何，卻鮮少有明確的研究數據，以至於究竟植生對河床或護岸之保護成效如何，並無法有實證資料的支持。基於此，本研究以大屯溪及蓬萊溪現地土壤，分別模擬裸土水道與植被水道兩種環境；觀察於不同流速條件下之沖刷情形，以瞭解河溪土壤自身抗沖刷之耐受極限與反應機制，以及植被對河床或護岸土壤產生的保護作用，可以更精確掌握河溪整治工程中正確的河床與護岸處理技術，提供河岸邊坡工程設計施工時的參考依據。研究利用壓克力雙槽式模擬水道，分實驗組與控制組進行不同流速變化之比較，在流速方面，控制組維持一定流速，實驗組則每三週調整流速一次，並加以收集沖刷下來之土壤進行物性分析。實驗過程中以植物燈提供固定光照時間、維持固定水槽傾斜率（2%）。實驗結果發現，在裸露土壤表面會自行形成藻膜，而形成時間較植被水道快，判斷應與裸土採光較佳有關；藻膜成份經分析包括念珠藻、顫藻與舟型藻等，藻膜的生成對土壤表層之坋土具有保護作用。於各階段沖刷分析結果發現植被環境可改善其水道沖刷情形比裸土環境來的好。

關鍵字

實驗水道 ； 生態工法 ； 河溪整治 ； 河床 ； 植生水道

並列摘要

Recently, there are many researches concerning the stream rectification in the field of ecological engineering. However, most studies emphasized the safety of engineering or the efficiency of ratio of green cover. There has been relatively little field evidences to verify the difference between naked riverbed/streambank and vegetated river bed/streambank when washed out by different flow velocities. This study was carried out in an experiment flume to compare the eroded response of naked riverbed and planted riverbed with different flow velocities. And then examined the tolerant limitation and flow resistance mechanism of the riverbed and observed the protection role of vegetation to the riverbed and streambank. The final purpose is to conduct the dredging technology correctly as well as to provide concerning data during design and construction period for the riverbed and streambank. The simulated channel was constructed with transparent acrylic panels and was separated into control group and experimental group with different flow velocities. The control group kept a fixed velocity while the flow velocities of the experimental group were adjusted every three weeks. Eroded soil was collected and physical characters were analyzed thereafter. Plant lights were used and set the illumination time. Slope of the channel was set on 2%. Study results showed that the algal mats would form automatically, including Anabaena azollae, Oscillatoria, and Navicula sp. These algal mats played a topsoil protection role especially for the silt. As about erosion analysis result, the planted riverbed could improve the canal erosion situation better than naked riverbed.

並列關鍵字

Experiment Flume ； Ecological Engineering ； Streams rectification, riverbed ； vegetated channel

參考文獻

[13] 朱榮華等 (2005)，「根系變形模式與含根土壤剪力強度之研究」，中國技術學院學報第27期。

[19] 林信輝、楊宏達、陳意昌 (2005/01)，「九芎植生木樁之生長與根系力學之研究」，中華水土保持學報，第36期第2卷，第123-132頁。

[25] 陳秀婷、吳瑞賢、陳致向、游新旺、朱榮華、陳主惠 (2006)，「含根土壤剪力強度之實驗量測與數值分析」，第十五屆水利工程研討會，第112-119頁。

[26] 游新旺、陳主惠、朱榮華 (2006)，「根力模式對含根土壤剪力強度評估之影響」，第十五屆水利工程研討會，第177-184頁。

[14] 吳正雄 (1990)，「植生根力與坡面穩定關係之研究」，國立台灣大學森林學研究所博士論文，台北。