| 摘要: |
| 三峡水库蓄水运行后，长江中下游崩岸强度增强，而崩岸具有隐蔽性和突发性，使得崩岸界定与评估具有一定难度。选取长江中下游的向家洲、七弓岭和成德洲作为3个典型河段，基于多源遥感影像和实测地形资料，分析了崩岸界定的主要指标（岸坡坡比、滩槽高差、坡脚侵蚀度、主流贴岸距离和岸线变化），确定了5个指标的阈值，并使用模糊层次分析法确定指标的权重。结果表明：主流贴岸距离和岸线变化是影响崩岸的主要原因，其权重分别达到0.40和0.25；岸坡坡比、滩槽高差和坡脚侵蚀度次之，三者的权重在0.10-0.15。向家洲的岸坡坡比和坡脚侵蚀度分别为0.04和0.1，七弓岭分别为0.50和0.16，成德洲则均为0.2。这3个河段的滩槽高差均大于15 m，岸线变化阈值为0-0.5 m，主流贴岸距离与河宽之比的阈值为0.3-0.4。 |
| 关键词: 崩岸 界定指标 指标阈值 岸线变化 模糊层次分析法 |
| DOI： |
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| 基金项目:国家重点研发计划课题(2023YFC3209502)；湖北省技术创新重点研发计划项目(2023BCB110) |
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| Indicators and threshold of bank failure quantification of typical reaches in the middle and lower Yangtze River |
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Deng Jing1, Li Zhiwei1, YUAN Jing2, CHEN Kebing2
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1.State Key Laboratory of Water Resources Engineering and Management,Wuhan University;2.Bureau of Hydrology, Changjiang Water Resources Commission
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| Abstract: |
| After the operation of the Three Gorges Reservoir, the intensity of bank collapse has significantly increased in the middle and lower Yangtze River, in which bank collapses show concealment and suddenness, making the quantification and assessment of bank collapse challenging. Three typical reaches, Xiangjiazou, Qigongling, and Chengdezhou along the middle and lower reaches of the Yangtze River were selected. Based on multi-source remote sensing images and topographic data, the indicators for quantifying bank collapse were analyzed, including bank slope ratio, elevation difference of the beach-trough, toe erosion degree, distance of main flow to bank, and bankline change. Thresholds for these five indicators were quantified, and furthermore the fuzzy analytic hierarchy process was used to determine the weights of the indicators. The results indicate that the distance of main flow to bank and bankline change are the primary factors influencing bank collapse, with weights of approximately 0.4 and 0.25, respectively. The bank slope ratio, elevation difference of the beach-trough, and toe erosion degree are the secondary factors, with weights ranging from 0.1 to 0.15. The threshold values for the indicators of bank collapse differ among the various reaches: the bank slope ratio and toe erosion degree for Xiangjiazou are 0.04 and 0.1, respectively;0.5 and 0.16 for Qigongling; and both are 0.2 for Chengdezhou. In all three reachers, the elevation difference of the beach-trough is over 15 m, the threshold for bankline change between 0 and 0.5 m, and the ratio of main flow-bank distance to channel width between 0.3 and 0.4. |
| Key words: bank failure quantification indicators indicator threshold bankline change fuzzy analytic hierarchy process |
