湿陷性黄土地区明渠陡槽加墩消能工优化试验

Experimental Study on Optimizing Energy Dissipation by Adding Pier to Steep Chute of Open Channel in Wet Collapsible Loess Area

明渠陡槽加墩是一种高效消能工布置方式,在特定条件下具有很高的技术竞争优势,但目前国内相关研究甚少。针对甘肃庆阳小崆峒沟雨水下塬排放工程的明渠陡槽加墩段进行了1∶30大比尺水工模型试验研究,试验发现初步方案沿程水流流态不稳定,存在向外泼溅溢出现象,危及黄土边坡的结构稳定。为此对初步方案进行了优化研究,试验发现,通过缩短消能墩排距,可以显著减小水面波动,使沿程水深分布均匀,流速降低,沿程不再出现水流向外泼溅溢出现象。消能墩排距由H/i缩短至0.5H/i后,在最大设计流量工况下,水面波动减小72.5%,平均流速降低40.1%,总消能率由87.9%提高至94.6%。

Adding piers to open channel chute is a highly efficient approach for enhancing energy dissipation,and holds a significant technological edge especially under specific conditions.This approach remains relatively unexplored within China’s research fields.We conducted a 1∶30 scale hydraulic model test on adding piers to the open channel chute of a rainwater drainage project in Xiaokongtong gully,Qingyang,Gansu.The initial design revealed that the flow regime was unstable,characterized by outward splashing that potentially harms the structural integrity of the loess slopes.In response,we refined the original design by reducing the spacing between the energy dissipation piers.This modification significantly stabilized the flow.Specifically,reducing the pier spacing from H/i to 0.5 H/i under peak flow conditions achieved a 72.5%reduction in water surface fluctuation and a 40.10%decrease in average flow rate,leading to a more uniform water depth distribution along the channel and eliminating the splashing.Moreover,the total energy dissipation rate improved markedly,increasing from 87.9%to 94.6%.