丁坝群间取水建筑物局部流场及其冲淤变形的试验研究

Local Flow Field and Scour near the Water Intake Project between Spur Dikes

本文结合黄河宁夏某河段丁坝群间设置取水建筑物的工程实际,采用正态动床模型,研究了丁坝群掩蔽条件下取水建筑物附近的流场特性及其局部冲淤变形规律.研究表明,丁坝群间设置取水建筑物,其局部流态及冲淤变形主要受到丁坝间回流及坝后扩散主流的控导.现状条件下,取水建筑物前流态不受回流的影响,回淤泥沙不危及取水安全,而扩散主流顶冲取水建筑物,形成较大局部冲刷;设置上挑式淹没构筑物,可极大减轻局部冲刷,比较了几种上挑式减冲设施,得到了较优化的体型及上挑角;合理下延上丁坝可有效发挥丁坝对水流的控导作用,既可形成有利的取水态势,又可减小顶冲作用,有效缓解局部冲刷.研究成果可为类似的工程实际提供参考.

In combining with a water intake project in Ningxia section of Yellow River, the flow field and local scour and deposition deformation features around the project shielded by the spur dikes were investigated using undistorted movable-bed physical model. The results showed that the local flow pattern and scour near the project were mainly conducted by the backflow between spur dikes and the diffusing mainstream. Under the current conditions, the flow pattern in the front of water intake structure is free of back flow, and the back silting sediment does not endanger the safety of water intake, but the diffusing mainstream rushes the project and results in serious local scour. When up-oriented submerged type diversion facilities are added, the local scour can be greatly reduced. The optimizing configuration and orientation angler of diversion facilities were obtained. Extending the up spur dam in a reasonable manner can achieve a more favorable flow condition for water intake, so that rushing was alleviated and local scour was diminished. These results can provide reference for the design of similar engineering.