X Water Conservancy Hub Spillway Experiment Research

The spillway is the key component in the whole reservoir, which is used to sluiceflood that is beyond the planned reservoir capacity, to prevent flood from overflowingthe crest and to guarantee the safe operation of the water retaining structures and otherrelated buildings. Whether the spillway can operate smoothly or not concerns the safetyof whole hydro junction. After studying previous dam accidents, the author finds thespillway contributes a great proportion to these accidents due to its inadequate dischargecapacity, defective designs or improper operation. It is necessary to make experimentson the spillway physical model and then optimize it.In this paper, a certain reservoir is chosen as the research object. According to relevantdata, model experiments are conducted on the optimization choices of aerator, flipbucket, pier and guide wall in a bank-run spillway. First, make research on water flowpattern of the original design. By analyzing the results, point out the problems in theoriginal design, give reasonable suggestions and put forward a recommended pattern ofthe spillway. Second, basing on this recommended pattern, make experimental studieson different working conditions respectively. The results are as follows:When the sluicegate is fully open or on orifice outflow conditions, the discharge coefficient at all levelswill increase slowly with the raise of flow, and gradually tends to be stable at high waterlevel. The spillway has super drainage ability and can satisfy the requirement of flooddischarge capacity.Under the recommended spillway pattern, the water flow patterntends to be normal and in the control section and the chute the depth of water decreasesgradually. In the chute, the rhombus shock wave hammers sidewalls while in someparts the height of water-wing is above the sidewalls. So it is suggested that relevantprotective measures should be taken in this place. There are negative pressures along thespillway in all working conditions. The water spreads in all directions after be carriedout by the flip bucket. The circumfluence appears in the left bank but not in the rightbank while the flow velocity is higher at bank sides. With more and more water flow,scour holes are pushed to the downstream, the scouring becomes severer and the depthof scour holes has increased gradually.