潮汐多汊河段滩槽水沙交换特性研究与应用——以长江通州沙河段为例

Study on characteristic of flow-sediment exchange between beach and channel at multi-branch tidal reach and application: case of Tongzhou Sand Shoal Reach

通州沙河段是长江南京以下12.5 m深水航道工程建设中的六大碍航河段之一,呈弯曲多汊河型,滩槽交错,涨落潮期间滩槽水沙交换量大,航道治理难度高。利用现场ADCP和多任务坐底水沙观测系统,获取了滩面窜沟和汊道内水沙运动资料,分析了滩槽水沙运动交换基本特性。针对通州沙中水道半旋转流水沙交换特征,结合现场测量和理论分析成果,研究了不同潜堤高程下的水沙拦截效果。为增强主水道碍航区水流动力,建议适当延长和抬高中水道附近过渡段潜堤长度和高程。

Tongzhou Sand Shoal Reach,a branch reach with bent and crisscross swales,is one of the six navigation-obstructing reaches in 12. 5m deep-water navigation channel project construction at the lower Yangtze River in Nanjing,flow and sediment exchange in a large quantity at swale during ebb and flow,so the channel regulation is difficult. By utilizing the field ADCP and multi-task landing flow and sediment observing system etc.,the data of flow-sediment movement as well as exchange features in ditches on beach surface and branches were gained and analyzed. Aiming at the characteristics of flow-sediment exchange of semi-swirling flow in the middle waterway of Tongzhou Sand Shoal and in combination with the field measurement as well as the theoretical analysis achievements,the water and sediment interception ratio at different submerged dike elevation has been researched. It is suggested that the length and elevation of the submerged dike in the transition section should be increased.