Author(s): A. M. Shvainshtein
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Keywords: No Keywords
Abstract: The breaking pattern of ice blocks is greatly dependent on drawdown of water levels at entrance to free-flow wasteways. Generalization of the data on the water level drawdown makes it possible to evaluate the surface level differential along the length of the ice blocks. The mean dimensionless outline of the free surface depends on the relationship between the water head at the weir crest H and the design head. For a 2-D idealization, the water level drawdown at the upstream face of unfinished dam would be (0.085±0.1) H. Comparing to the upstream level, the relative free surface drawdown would depend on the distance from the upstream face x and from H. For a weir with wide sill and piers the mean drawdown at the approach to the weir would also be determined by a relative length of the weir sill. Given is an approximate assessment of the level drawdown at the entrance under significant submergence of the weir. Presented are computation charts for determination of free surface drawdown along the bank and the upstream portion of a cofferdam.
Year: 2004