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潜坝作为一种河道整治工程措施,具有增加河底糙率、增加河道阻力、减缓流速、促进淤积、壅高水位、调整河床比降等功效。本文通过Delft3D建立了长江南京河段八卦洲的二维非恒定流数学模型,结合八卦洲的水文资料进行参数的率定,并在枯水、中水两种流量级别下对模型进行水位、流速和汉道分流比的验证。基于两级流量下12座单个潜坝五种高程的不同方案,分析得出潜坝对左汊的分流影响主要与潜坝阻水比和高程有关,次要因素是潜坝与分汉口的距离和水流的流量级别。计算结果表明:两种流量条件下,所有单个潜坝在-10m高程时达到方案实施后左汊分流比最大值,左汊最大分流比增加值为2.60%。潜坝对上游水位产生壅水,尤其是-10m高程的潜坝,其影响范围一直追溯到模型起点位置,此处最大影响值枯水流量时为0.03m,中水流量时为0.05m。
Submerged dam, as a kind of river regulation engineering measures, has the functions of increasing the roughness of the river bottom, increasing the resistance of the riverway, slowing the flow rate, promoting siltation, high water level and adjusting river bed ratio. In this paper, Delft3D established a two-dimensional unsteady flow mathematical model of Bagua Chau in Nanjing Section of the Yangtze River, combined with the hydrological data of Bagua Island to determine the parameters, and the water level, velocity And Chinese channel diversion ratio verification. Based on the different schemes of five elevations of 12 single submarines under two levels of flow, it is concluded that the influence of submarine dam on the left subduction is mainly related to the water blocking ratio and elevation of submarine. The secondary factor is the distance between submarine dam and sub-Hankou And the flow of water flow level. The calculation results show that under the two flow conditions, all the single submersible dam reaches the maximum value of left 汊 shunt when the single submersible is at -10m elevation, and the added value of left 汊 maximum shunt ratio is 2.60%. The potential impact of the submarine dam on the upstream water level, especially the submarine of -10m elevation, has been traced back to the starting point of the model. The maximum impact here is 0.03m for low flow and 0.05m for medium flow.