不同类型建闸河口闸下淤积模拟计算

Simulation of siltation downstream of floodgate in estuaries

针对闸下淤积问题建立三维水动力和泥沙数学模型,在挟沙能力公式中考虑浮泥的影响,采用枚举法和最小二乘法相结合率定公式中的参数,较好地反映了建闸河口概化物理模型闸下三维水流和含沙量分布。采用该数学模型研究了短引河河道型、短引河滩槽型和长引河河道型三种类型建闸河口闸下淤积特性。结果表明,在计算条件相同的情况下,建闸河口闸下淤积速率和淤积总量与闸下河道长度、滩槽宽度有关;短引河河道型闸下初始淤积速率最大,长引河河道型闸下初始淤积速率最小;长引河河道型闸下累积淤积厚度最大,短引河滩槽型闸下累积淤积厚度最小;长引河河道型闸下河道淤积总量最大,短引河滩槽型闸下河道淤积总量最小;闸下河道两侧滩地的归槽水对闸下河道减淤作用明显。

In this paper,the variation of hydrodynamic characteristics and sediment transport at the downstream of floodgates in different types of estuaries are investigated by use of an established three-dimensional model of sediment transport.A sediment-carrying capacity formula considering fluid mud is applied in the model.The parameters in the formula are calibrated by the enumeration method and the least square method.The siltation characteristics and process in three types of floodgates in estuaries,which are a short river channel,a short river channel between shoals and a long river channel,are studied with the model.The results show that the siltation rate and the total siltation at the floodgate are related to the length of the river downstream of the floodgate and the width of the shoal under the same calculation conditions.Of all the three types of estuaries,the initial siltation rate is the highest in the estuary with a short river channel downstream of the floodgate and the lowest in the estuary with a long river channel;the total fill up thickness and siltation is the greatest in the estuary a with long river channel downstream of the floodgate and the least in the estuary with a short river shoal.The water coming from the shoal shows an obvious effect in reducing the siltation in the downstream channel.