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| 黄河下游河床持续调整过程中输沙能力变化规律 |
| Variations in sediment discharge capacity under continuous channel adjustments in the Lower Yellow River |
| 投稿时间：2025-05-13 修订日期：2025-07-31 |
| DOI： |
| 中文关键词: 进口水沙 主槽形态 床沙组成 河床冲刷效率 平衡输沙 黄河下游 |
| 英文关键词: Incoming flow regime channel geometry bed material composition channel erosion efficiency equilibrium sediment transport Lower Yellow River |
| 基金项目:国家自然科学基金资助项目U2243238、U2243237、U2443222; 国家重点研发计划课题2023YFC3209304 |
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| 中文摘要: |
| 由于中上游水库建设等强人类活动影响，近50年来黄河下游水沙情势和河床边界条件剧烈改变。下游河床由持续淤积转为持续冲刷，且近期河床冲刷幅度减缓，河道输沙规律发生显著变化。基于1971~2022年实测水沙、地形及床沙组成资料，首先计算黄河下游河床冲刷效率调整过程，并分析其影响因素；进而提出综合考虑多边界条件影响的河床冲刷效率计算方法，并动态预测了河床持续调整过程中维持下游冲淤平衡的临界水沙条件。结果表明：①1971-2022年黄河下游经历了缓慢淤积期-快速淤积期-快速冲刷期-缓慢冲刷期，在小浪底水库拦沙后期（2008-2022年），黄河下游多年平均河床冲刷效率仅为拦沙初期（2000-2007年）的一半。②来沙系数的大幅降低以及主槽的下切导致挟沙力下降，床沙粗化则使河床补给不足，这些综合作用导致河床冲刷效率随时间降低；进而构建了综合考虑进口水沙、主槽形态与床沙组成影响的河床冲刷效率计算关系，公式决定系数为0.80，能较准确反映近50年河床冲刷效率的调整过程。③黄河下游平衡输沙的临界来沙系数随河床边界综合参数的增大呈现先增后减的趋势，拦沙后期黄河下游平衡输沙的沙量阈值较拦沙初期减少23%。 |
| 英文摘要: |
| The incoming flow regime and channel boundary conditions in the Lower Yellow River (LYR) have significantly adjusted in recent 50 years, owing to human activities such as reservoir construction in the upper and middle reaches. The channel in the LYR experienced continuous aggradation and subsequent continuous degradation, but the trend slowed down in recent years. Based on the measurements of hydrological data, cross-sectional profiles and bed material, the variation in channel erosion efficiency was firstly calculated and analyzed. A calculation method of channel erosion efficiency considering the influences of various factors was then proposed. Finally the critical flow regime was determined to keep the equilibrium of channel evolution under continuous channel adjustment. Results indicate that: ① the channel evolution processes could be divided into four periods after 1970, including slow aggradation period, rapid aggradation period, rapid degradation period and slow degradation period. The channel erosion efficiency during the later sediment detention stage (2008-2022) has reduced to half during the initial sediment detention stage (2000-2007). ② The temporal decreases in these factors, including incoming sediment coefficient, bed material supply and geomorphic coefficient, resulted in the temporal decline in channel erosion efficiency. An empirical relationship was further established between channel erosion efficiency and these factors, with the determination coefficient being equal to 0.80, which was able to reflect the temporal variation in channel erosion efficiency. ③ The critical incoming sediment coefficient varied with the channel adjustment, and the critical incoming sediment amount reduced by 25% during the later sediment detention stage compared with that during the initial sediment detention stage. |
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