Uplift pressure and design of weirs with two sheet piles

Summary

Models of weirs with two sheet piles have been investigated for the pressure distribution. Three series of experiments were carried out. In the first series the sheet piles were of equal length at the heel and toe; in the second series, they were of unequal lengths but again situated at the heel and toe; and in the third series, the piles were of equal length but not at the heel and toe. The results obtained are represented graphically in Figs. 1 to 8. The efficiencies of the sheet piles, with respect to their position under the floor and with respect to their length, have been examined.

Employing the graphical results obtained in the investigation, a method of obtaining the uplift pressures for a new design has been illustrated. The results of the graphical solution thus obtained were tested experimentally. The results by the two methods are found to agree giving a maximum difference of only 2“5 per cent. for the uplift pressure and this not at an important point. Attention has also been drawn to the fact that as the toe of a weir is its vulnerable point, weir design must commence from the down-stream end, so as to control the exit gradient.