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渭河下游是典型的弯曲型河道,过去60年频繁地发生自然裁弯,其触发原因、形成过程和演变规律缺少深入的研究。渭河下游的裁弯是河湾横向演变到一定阶段后在汛期洪水冲刷作用下发生临界突变,直接影响河道平面形态、上下游河床冲淤和局部河段的防洪安全。基于原型观测、水沙数据(1960-2013)和遥感影像(1990-2015),分析了渭河下游裁弯事件的水沙条件、影响因素和裁弯时空演变过程及其原因。渭河下游发生的18次裁弯的主要原因是受三门峡建库后渭河下游边界条件的改变,包括潼关侵蚀基准面淤积抬高,凸岸边滩及内侧平原缺少粘性成分,抗冲性差,同时也受渭河下游来水来沙条件的变化及其高含沙洪水的影响。
The lower reaches of the Weihe River is a typical curved channel. Natural tailing frequently occurs in the past 60 years. The triggering reason, forming process and evolution are not thoroughly studied. The cut in the lower reaches of the Weihe River is a critical sudden change in flood season after the horizontal evolution of the river bay to a certain stage, which directly affects the plane shape of the river channel, the scouring of the upper and lower reaches of the river bed and the flood control safety of the local river sections. Based on the prototype observations, water and sediment data (1960-2013) and remote sensing images (1990-2015), the water and sediment conditions, influencing factors and space-time evolution of cut-bending in the lower reaches of the Weihe River and their causes were analyzed. The main reason for the 18 cuts occurring in the lower reaches of the Weihe River is the change of the lower Weihe River boundary conditions after the Sanmenxia reservoir was built, including the siltation and elevation of the Tongguan erosion reference plane, the lack of viscous components on the bank of the convex bank and the inner plain, the poor impact resistance, Change of incoming and outgoing fresh water and sediment in the lower Weihe River and its impact of high sediment concentration.