分汊河段河中布置船闸水沙碍航特性研究

分汊河段的汇流口水沙条件复杂多变,为保证航道稳定及船舶航行安全,分汊河段水利枢纽平面布置时一般将通航建筑物布置于其中一个汊道的靠岸侧。受工程建设条件限制需将通航建筑物布置于分汊河段河中时,既存在流态碍航问题又存在泥沙淤积碍航问题。针对布置于分汊河段洲尾汇流段的已建桃源枢纽船闸存在的通航条件较差的问题,采用整体定床水流、定床输沙与遥控自航船模试验相结合的研究手段,开展了船闸下游口门区水沙碍航特性试验研究。结果表明:水流条件是导致流态碍航与泥沙淤积碍航的根本因素,左、右汊不同下泄水流在汇流段形成单边突扩或水流掺混交汇,致使下游口门区所处的汇流段水流流态差且推移质泥沙落淤碍航,分汊河段船闸河中布置应慎重考虑。

Study on the navigation-obstructing characteristics of water and sediment by the ship lock arranged in the middle of the river in a branching river

The water and sediment conditions of branching rivers are complex and changeable. In order to ensure the stability of the channel and the navigation safety of ships, navigation structures are usually arranged at the shore side of one of the branches when designing the layout of the water conservancy project of a branching river. Due to the limitation of engineering constructions, it is necessary to arrange the navigation structures in the middle of the branching river, which disturbs the flow patterns and obstruct the navigation from sediment deposition. Based on the poor navigation conditions of the existing locks of Taoyuan Junction, which are arranged in the confluence section of the island end of the branching river section, the experimental study on the characteristics of water and sediment obstruction in the downstream gate area of the lock was carried out by combining the integrated fixed-bed flow, fixed-bed sediment transport and remote control self-propelled ship model tests. The results showed that the flow condition was the underlying cause of flow obstruction and sedimentation obstruction. The left and right branch drainages of water flow in the confluence formed a sudden unilateral enlargement or mixed flows, causing a bad flow regime and bedload sediment silting obstruction at the entrance area of the downstream section. Therefore, branching river lock arrangement should be carefully considered in the river.