Experimental study on optimal layout of grid desilting gallery

Based on the desilting research of one scheduling project in the southwest of China, the method of setting grid desilting gallcry before the desilting tunnel is put forward to expand the scope of the scouring funnel before the dam and solve the problem of sediment deposition at the power station water intake. The experimental results show that, in the design of a grid desilting gallery, the width of the grid gallery should not be smaller than that of the desilting bottom in-take, the size of the grid orifice should be in the range of 1.5 m-2.0 m along the flow direction, and the grid spacing should be 3-5 times the size of the grid orifice. The discharging ability of the desilting bottom intake will decrease after the grid desilting gallery is added. The average of the decrease rates is about 5%-10%. The scouring funnel draws in the longitudinal direction before the dam obviously after the construction of the grid desilting gallery.