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在大洪水期行洪滞洪沉沙是黄河下游宽滩区的主要功能之一。近十几年来,随着黄河水沙的变化和小浪底水库的建成运用,对宽滩区运用方式的争论更为激烈,却一直缺乏系统的对比研究。为此,黄科院利用小浪底至陶城铺河道实体模型,采用2013年汛前地形,开展了黄河下游宽滩区是否修建防护堤两种不同运用方式下,大洪水期的洪水演进试验,通过对比分析不同运用方式下的下游河道在冲淤演变、洪水位变化和滩区防洪安全等方面的问题,探讨了大洪水条件下黄河下游河道冲淤及滩区的安全形势,以期为黄河下游河道治理措施的决策提供科学的参考依据。结果表明,宽滩区修建防护堤后,中常高含沙洪水条件下主槽淤积量小于不修防护堤方案,大洪水条件下主槽冲刷量大于不修防护堤方案,说明主槽过流能力和输沙能力均有所增大。但是,修建防护堤后的嫩滩淤积量,两种洪水条件下均呈现出明显大于不修防护堤方案,河道的横断面形态和“二级悬河”形势均有所恶化。同时,由于目前地形条件下夹河滩以上河段主河槽过流能力达到了6 000m3/s,洪水向下游的演进速度和水量明显增加,导致高村以下的洪水位比不修防护堤时显著提升,增大了高村以下河段的防洪压力,滩区的防洪安全受到严重威胁。
Flooding and sediment deposition during the flood season is one of the major functions of the beach area in the lower Yellow River. In recent decades, with the change of water and sediment in the Yellow River and the construction of Xiaolangdi Reservoir, the debate over the mode of operation of the beach area has become more fierce. However, systematic comparative studies have been lacking. To this end, the Yellow Academy of Sciences to use Xiaolangdi to Taochengpu river solid model, the use of the pre-flood season in 2013, carried out in the lower reaches of the Yellow River is to protect the dike two different ways to use the flood evolution test, through The paper analyzes the problems of scouring and silting evolution, change of flood level and flood control safety of floodplain under different operational modes, and discusses the scouring and silting of the lower Yellow River under flood conditions and the safety situation of the floodplain so as to be the lower reaches of the Yellow River Governance decision-making to provide a scientific basis for reference. The results show that after the construction of the bank, the sedimentation of the main channel under medium-high silt-flood conditions is smaller than that without repairing the dike, and the main channel erosion under flood conditions is greater than that without repairing the dike, which shows that the overcurrent capacity of the main channel And sediment transport capacity have increased. However, the siltation of the tender beach after the construction of the dike was significantly greater than that of the unprotected dike under both flood conditions. The cross-sectional shape of the river channel and the “secondary suspended river” situation were both deteriorated. At the same time, due to the over-flow capacity of the main channel above Jiahetan reaches 6,000m3 / s under the current topographic conditions, the evolution rate and amount of water flowing downstream significantly increase, resulting in a significant increase in the flood level below high village compared with no protection of the dike, Increasing flood control pressure below the high village, flood control safety of the beach area is seriously threatened.