應用防沖蝕氈於渠床穩定之研究

A Study of Soil Erosion Control Mat Applied on Channel Bed Stability

陳慶恆(Ching-hengChen)

指導教授 ： 鄒禕博士 ； 謝啟萬博士

國立屏東科技大學/工學院/土木工程系所/碩士(2013年)

https://doi.org/10.6346/NPUST.2013.00045

摘要

本研究使用百喜草與防沖蝕氈作為試驗材料，探討植生與防沖蝕氈結合對於渠床穩定之效果。試驗將影響渠床穩定之因子分為水理特性及植生特性。水理特性之四項參數為流速V、流體密度ρ、重力加速度g、水深h，而植生特性之四項參數為根密度RD及根長密度RLD、葉長LL、土壤裸露率AB。使用因次分析將影響因子推導出五項無因次參數，建立各參數與土壤沖蝕度相互間之關係。渠床沖蝕試驗分為裸土沖蝕、植生沖蝕、防沖蝕氈沖蝕、植生防沖蝕氈沖蝕等四個部分來進行試驗。研究結果顯示，防沖蝕氈確實能夠降低其土壤沖蝕度，鋪設防沖蝕氈於裸土上可降低86.8~96.9%之土壤沖蝕度。植生試驗樣本之土壤經過植栽百喜草後，土壤被草株所保護，水流經過草株時減少了水流對於土壤的撞擊力，而葉片使水流更加的緩慢，故其保護能力顯著，與裸土之土壤沖蝕度比較，相對的減少99.2~99.5%。鋪設防沖蝕氈且植生後，增加了植株的覆蓋物，使土壤沖蝕降低了98.6~99.4%之間，與植生之試驗樣本相較之下，植生之試驗樣本比植生防沖蝕氈之試驗樣本更加能夠保護土壤被沖蝕。

關鍵字

防沖蝕氈 ； 渠床沖蝕 ； 植生 ； 沖蝕度

並列摘要

This study uses the Bahia grass and erosion control mats as the test materials to explore the combination of vegetation and erosion control mats for the channel bed stability effect. The test divides the impact factors of channel bed stability into hydraulic and vegetation. The hydraulic factors include four parameter for velocity v, and flow density ρ, gravity g, depth h, while vegetaion factors include four parameter for root density RD and root length density RLD, leaf length LL, and bare soil rate AB. The study deducted dimensionless parameters by dimensional analysis, to build up the relationship between those parameters and soil erodibility. There are four types of channel bed, bare soil, vegetated soil, erosion control mat covered soil, and vegetated erosion control mat covered soil, are set up for erosion test. The results show that the erosion control mat placed on the bare soil can reduce the soil erodibility to about 86.8~96.9% ; and the soil with Bahia grass can reduce soil erodibility to about 99.2~99.5%, both compared with bare soil with no protect. From the flume experiment soil are protected with turf strains of Bahia grass, because the flow through turf strains will decrease velocity and reduce the erosion impact on channel bed soil. The result also show that vegetated erosion control mat place on soil can reduce soil erodibility to about 98.6~99.4%, quite close to the result of Bahia grass planted only soil. However, the experiment data that the diameter Bahia grass root from vegetated erosion control mat soil sample is smaller than those from soil with Bahia grass planted only sample.

並列關鍵字

Erosion Control Mat ； Channel bed Erosion ； Vegetation ； Erodibility

參考文獻

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