关键词: 岸滩稳定性;层次分析法;指标体系;长江中下游;太平洲环岛;扬中河段;

Abstract: The beach stability of the middle and lower reaches of the Changjiang River is affected by many interrelated and mutually restricted factors.Most existing studies examined these factors separately，thereby being unable to evaluate beach stability quantitatively and comprehensively by considering different factors simultaneously.In this paper，based on the major factors affecting the beach stability of the middle and lower reaches of the Changjiang River，a beach stability evaluation index system （BSEIS） was established，which covered bank boundary，river dynamic，river regime conditions，human activities，etc.Then selecting the Taipingzhou roundabout of the Yangzhong reach as the research object，a hierarchical structure model of beach stability was constructed by using the analytic hierarchy process （AHP） and BSEIS.The judgment matrix was established to solve the index weight，and the index threshold and scoring criteria were given.The scoring evaluation of beach stability around the roundabout was carried out，and the reliability of the stability evaluation results of the beach section included in the list of beach collapse warning sections in Yangzhong City was verified.The analysis results showed that，the beach in the studied area were mainly basically-stable，accounting for 67% of the total length of the evaluated reach，the remaining 33% being either stable or relatively unstable banks.The comparison reasults furtherly demonstrated that，the non-early-warning section was the most stable，followed by the municipally administered section，whereas the provincial key section was the least stable.Moreover，during the non-early-warning section，the segment between Xinning Village and Huawei Village received a relatively low score，needing to be included in the list of beach collapse warning reaches for intensive monitoring.The evaluation results were close to the warning level of bank collapse and the actual position of bank collapse，indicating that the BSEIS can better reflect the beach stability in this section.Combined with the characteristics of the river，the index system can be widely used in the stability evaluation of different sections of the middle and lower reaches of the Changjiang River after the appropriate modification of index weight and scoring criteria.

Key words: beach stability；analytic hierarchy process；index system；middle and lower reaches of the Changjiang River；Taipingzhou roundabout；Yangzhong reach of the Changjiang River