Study on Hydraulic Experiments in a Grassed Channel
碩士 === 國立中興大學 === 水土保持學系所 === 95 === In order to protect the ecological system, the proportion of using concrete to construct drainage facilities should be reduced, and some non-major drainage facilities could be replaced with grassed channels for reducing the use of concrete. This experiment was...
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| Format: | Others |
| Language: | zh-TW |
| Online Access: | http://ndltd.ncl.edu.tw/handle/55880867320450009274 |
| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 95 === In order to protect the ecological system, the proportion of using concrete to construct drainage facilities should be reduced, and some non-major drainage facilities could be replaced with grassed channels for reducing the use of concrete. This experiment was executed with three kinds of grass and two kinds of soil to analyze the grassed channel design and to seek the best one.
The result shows that the velocity estimated by Manning’s formula is always over-evaluated and larger than the measure one whatever the channel bottom and the vegetation are. The over-evaluated degree of Centipede grass (Eremochloa ophiuroides) is about 1.2 to 3 times, and the other ones of Bermuda grass (Cynodon dactylon) and Carpet grass (Axonopus affinis) are about 1.2 to 4 times.
In the application, the estimated discharge by Manning’s formula is over-evaluated to a large degree, and the most one can be up to 44%. It shows that this method applied to drainage facilities design is often different from the fact easily.
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