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| 水库下游河道泥沙恢复饱和系数研究 |
| Research on the Saturation Coefficient of Sediment Recovery in the Downstream River Channel of the Reservoir |
| 投稿时间：2025-07-28 修订日期：2025-12-23 |
| DOI： |
| 中文关键词: 水库下游 恢复饱和系数 不平衡输沙 非饱和调整系数 |
| 英文关键词: downstream of reservoir recovery saturation coefficient non-equilibrium sediment transport unsaturated adjustment coefficient |
| 基金项目:国家自然科学基金长江水科学研究联合基金(U2240206,U2240224)；湖南省重大水利科技项目(XSKJ2022068-39)。 |
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| 中文摘要: |
| 泥沙恢复饱和系数是预测水库下游河床冲淤的核心参数，受限于相关参数计算公式的未知性与运算的繁琐性，难以在实践中广泛应用。基于不平衡输沙理论与垂向含沙量分布公式，通过垂向积分与输沙率平衡关系，推导并优化泥沙综合恢复饱和系数计算公式，提出（不平衡输沙时近底处含沙量与垂线平均含沙量比值）、（近底处挟沙能力与垂线平均挟沙能力比值）的物理推导方法，在计算过程中近底含沙量的数值难以确定，基于韩其为引入的非饱和调整系数c，将的计算转为非饱和调整系数，但非饱和调整系数确定也存在较大困难；依托水槽试验，发现床沙粒径为0.28mm、0.18mm条件下系数与呈幂指数关系，拟合参数，验证均匀沙条件下计算公式对动态变化的计算精度；结合三峡水库下游典型河段2003—2023年水沙数据，提出了底部恢复饱和系数经验公式，进而明确了泥沙综合恢复饱和系数变化过程，提出的计算方法可用于数值模拟冲淤预测，但在其他粒径工况、在床沙极端粗化场景下的适用性需深化，为后续研究明确方向。 |
| 英文摘要: |
| Abstract: The sediment recovery saturation coefficient is a key parameter for predicting riverbed scour and siltation downstream of reservoirs. Due to the unknown nature of calculation formulas for relevant parameters and the complexity of calculations, it has been difficult to apply this parameter widely in practice. Based on the non-equilibrium sediment transport theory and the vertical sediment concentration distribution formula, this study derives and optimizes a calculation formula for the comprehensive sediment recovery saturation coefficient?. Specifically, through the vertical integration and sediment transport rate balance relationship, a physical derivation method is proposed for ?(the ratio of near-bed sediment concentration to vertical average sediment concentration during unbalanced sediment transport) and??(the ratio of near-bed sediment-carrying capacity to depth-averaged sediment-carrying capacity). During the calculation of , the near-bed sediment concentration is difficult to determine. Based on the unsaturated adjustment coefficient?c?introduced by HAN Qiwei, the calculation of??is transformed into determining the coefficient?c. However, there is also great difficulty in determining?c. Relying on flume experiments, it is found that under bed material particle sizes of 0.28 mm and 0.18 mm, the coefficient?c??exhibits a power-law relationship with (the ratio of depth-averaged sediment concentration to the sediment-carrying capacity of flow). The parameters are fitted to verify the calculation accuracy of the formula for the dynamic change of?c?under uniform sediment conditions. Based on the flow and sediment data (2003–2023) from a typical reach downstream of the Three Gorges Reservoir, an empirical formula for the bottom recovery saturation coefficient is proposed, and the variation process of the comprehensive sediment recovery saturation coefficient is further clarified. The proposed calculation method can be applied to numerical simulation for scouring and silting prediction. However, the applicability of c under other particle size conditions and that of under the scenario of extreme coarsening of bed sediment need to be further explored, pointing the way for future research. |
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