南二高之邊坡保護工法效果

Effectiveness of Hillslope Conservation Engineering Methods along the South Second Highway

許中立(Chung-Li Hsu)

《坡地防災學報》 2卷2期 (2003/12) Pp. 71-81

https://doi.org/10.29995/JSHR.200312.0007

摘要

南二高橫跨高雄、台南與屏東三縣，沿線通過地質複雜的泥岩、砂岩與礫石層等地質區，興建時因開挖路塹切削邊坡而使地層穩定平衡受到破壞，再加上南部地區降雨強度大且集中，致使南二高從施工開始至完工通車以來，道路邊坡經常發生坍滑與破壞，本研究則利用調查沿線邊坡之基本特性，探討其相互間之關係。
由調查結果可知南二高沿線所施作的邊坡水土保持處理工法最主要的有七種，依序爲自由格框工法、預鑄格框工法、鋪植生帶、鋪土壤袋、鋪植生網、鋪網噴植法、布袋模毯工法等。就邊坡受損情形而言，發現僅以植生方法或單一種工程方法施作之受損程度都較嚴重，建議將來以採用複合型工法爲主，讓植生及工程方法都能發揮其效果。又植生覆蓋率與土壤沖蝕情形成反比之關係，當覆蓋率達50%以上，其沖蝕情形明顯好轉，覆蓋率大於70%者時幾無沖蝕溝發生。

關鍵字

南二高 ； 邊坡保護工程 ； 土壤沖蝕 ； 覆蓋率

並列摘要

The south second highway is one of important highways in southern area of Taiwan, which intersects three counties of Kaohsiung, Tainan and Pintung and includes main lanes and branches thereof from Hsinhwa, Tainan, to Chouzu, Pintung. The total length is 96 km. This highway also intersects complicated geological areas of mudstone, sandstone and gravel formations. Besides, while constructing the south second highway, the excavated slopes and cut slopes has caused the strata stability failed, and the rainfall intensity in south area is large and concentrated. So many landslides and failures occur in slopes along the national freeway, which shows there are many topics worth to discuss regarding the hillslope conservation engineering methods along the highway. Therefore, this study is to investigate the basic characteristics of slopes along the highway in discussing the relationships between the characteristics.
From investigation results, there are seven current slope protection methods along the south second highway, which are the free frame method, pre-cast concrete frame method, vegetation belt pavement method, soil bag pavement method, vegetation net pavement method, wire-netting with hydroseeding method, and bag and carpet method. In regard with the degree of damage, it is found that performing a single vegetation method or engineering method is worse to performing complex engineering method. Therefore, it is recommended to use complex engineering method to let both the vegetation method and engineering method go into effect. Results have shown that there is a negative relationship between the vegetation cover rate and soil erosion. As the vegetation cover rate is more than 50%, the soil erosion is conspicuously lower; As more than 70%, it has even no erosion gullies. Therefore, the success and failure of the hillslope conservation engineering methods along the south second highway are closely relating to their vegetation cover rate.

並列關鍵字

South second highway ； Hillslope conservation engineering methods ； Soil erosion ； Vegetation cover rate