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You are here : eLibrary : IAHR World Congress Proceedings : 35th IAHR Congress - Chengdu (2013) : THEME 3 - WATER ENGINEERING AND CIVILIZATION : Hydraulic Experimental Research of Stepped Spillway
Hydraulic Experimental Research of Stepped Spillway
Author : HOU Dongmei, WANG Caihuan, LIU Hui and YANG Xiaohong
Based on the 1:40 hydraulic cross section model experiment, the overflow pattern, pressure features of the dam face, aeration effect, the downstream energy dissipation and anti-scouring effect are studied of the stepped overflow dam. The experimental results show that the design scheme of stepped dam can form slip flow pattern under each feature discharge condition, the dam face pressure distribution is good without larger negative pressure, and the energy dissipation ratio is about 80%. Under the flood discharge conditions no 3 more than 480m \s, the water self-aeration of dam face is sufficient in general, no cavitation damage will occur. At PMF discharge or above, the aerating concentration of bottom flow of the first 50-step dam face is less than 5%, but flow velocity is more than 20m\s. It is possible that cavitation may happen on the dam face. In order to enhance the reliability of dam face aeration and reduce cavitation damage, based on a series of optimized experiment, the forced aeration facility of small flip bucket & tail-widened pier is set up at the initial step, the underneath of initial step can form a stable aeration passage, which can protect all dam face steps from cavitation-damage effectively. Above P=1% flood discharge, the total flow can jet beyond the apron, and the back slope ratio of scouring pit from the apron end is slower than 1:10. Below 180m3\s discharge, the flow falls on the apron, and the actually measured maximum instantaneous impact pressure is 5.39.81kPa. Considering the factors such as gateless control of crest outlet, it shall attach enough importance to the anti-scour protection of the dam toe area.
File Size : 544,577 bytes
File Type : Adobe Acrobat Document
Chapter : IAHR World Congress Proceedings
Category : 35th IAHR Congress - Chengdu (2013)
Date Published : 18/07/2016
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