渠与河交叉建筑物的裹头体形初探

Experimental study on optimal wraparound configuration of inverted siphons for water transfer canals crossing rivers

河渠交叉建筑物的裹头体形设计关系到河道上游水位壅高、河道演变以及总干渠的正常运行等重要问题。在前人研究的基础上,通过对南水北调中线一期工程渠道倒虹吸工程的裹头体形多种方案的试验比较,得出较优的体形为抛物线接圆弧,在此基础上探讨了影响裹头体型的主要因素。文中还对河与渠斜交时裹头设计参数的选取进行了定性分析。

The inlet and outlet construction of inverted siphon for canals crossing rivers contracts the river flow and experiences the erosion of river flow. For this reason wraparound levee is always adopted. The optimal wraparound configuration of the inverted siphon＇s inlet and outlet constructions for water transfer canals crossing rivers in the Middle Route South-to-North Water transfer Project was studied by model test. The flow field, maximum riverbed flow velocity and water head loss of the contracted river section for different schemes were measured. It was found that the parabolic curve connected with circular arcs was the best configuration. By adopting this configuration no separated flow occurred and the contracted flow can be extended smoothly in the downstream of the contracted section. On this basis the main factors affecting the configuration were investigated. Furthermore, the design parameters to be adopted for the crossing with arbitrary angle were discussed.