摘要
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 measure of river training measure, has many effects such as increasing roughness, increasing the flow resistance, slowing the flow rate, promoting siltation, obstructing the high water level, adjusting the riverbed gradient and so on. This paper used Delft3D to build a two- dimension unsteady flow numerical model on the Baguazhou braided channel diversion in Nanjing section of Yangtze River. This model was calibrated and verified by the measured Hydrological data in the field, and in the two levels of the model water flow , flow rate and the split ratio of branching path verification were made. Based on 12 single submerged dams elevation of five different programs in two flow levels, the paper got the main factors of submerged dams on the left diversion branch which were water-blocking ratio of the submerged and elevation related and secondary factors which were the distance of submerged dam and the flow bifurcation and flow level. The results showed that under two levels all in a single submerged dam, -10m elevation reached the maximum left shunt branch value after the implementation of the program, the largest left branch split ratio increase is 2.60%. Submerged dam lifted the upstream water level, especially the submerged dam -10m elevation , its sphere of influence had been traced back to the starting model position, where the greatest impact on the value of low flow was 0.03m, the middle water flow was 0.05m.
出处
《上海水务》
2016年第4期14-18,共5页
Shanghai Water
关键词
潜坝
八卦洲
数值模拟
Delft3D
分流
submerged dam
Baguazhou
Numerical simulation
Delft3D
water diversion
