采用二维数学模型，对成都市府河上游段河道裁弯取直工程进行了对比分析，探讨了弯颈落差全河段分摊和设置集中跌落两种不同裁弯取直方案对河道行洪的影响。结果表明，不同裁弯取直方案均会造成畸弯河道上游主槽水位降低和流速的增加，并引起老河湾水流动力的减弱；落差分摊方案对老河湾分流量及水流动力参数的消弱作用更大，上游河道水位降低更为明显；从流速沿程分布规律来看，设置集中跌落的裁弯取直方案将引起局部河段流速过高，对河道冲刷安全不利，且存在明显的噪声污染。但是，落差分摊方案将弯颈落差通过工程措施直接分摊到整治河段范围，更接近自然裁弯取直的河道演变过程，因此该工程方案更为合理。

This paper was devoted to the comparison work of the two cut-off plans on upstream of Fu River in Chengdu city with a 2D mathematical model. In the first plan, this elevation difference was assigned to one step-fall. In the second cut-off plan, the elevation difference of the curve reach was assigned to the whole river. Both plans would decrease the water level and increase the velocity of main river in upstream. Meanwhile the hydrodynamics of the curve reach was reduced. However, the first plan could cause more intensive change. In the second plan, the velocity of step-fall was too high to keep the stability of the channel under the local scour and too much noise would be created due to this high speed current. The first plan was similar to the natural cut-off river progress, therefore was more reasonable and safe.

国家科技支撑计划(2012BAB05B02)，国家自然科学基金项目(50949057)。