320 / 2024-02-29 15:16:44

Study on riverbank stability assessment method and its application in the Jingjiang Reach in the middle Yangtze River

bank collapse; riverbank stability; assessment index system; Jingjiang Reach in the middle Yangtze River

Under the impacts of the operation of upstream cascade reservoirs including the Three Gorges Project, sediment load entering the Jingjiang reach of the middle Yangtze River has been sharply decreased, resulting in the intensive river bed incision and a frequent occurrence of bank erosion event. The increased river morphology evolution would not only affect the channel stability, but also increase the flood control pressure, threatening economic and social development. However, owing to numerous influencing factors and complexity of the interaction mechanisms among the typical bank collapse influencing factors were selected as the evaluation index system by combining qualitative analysis with quantitative calculation. These factors include the characteristics of bank line status, geological conditions of bank slope, completeness of bank protection engineering, hydrodynamic conditions, erosion depth of near-bank riverbed, height difference of beach and riverbed, ratio of the bank slope. Then, a riverbank stability assessment method was established, and the risk of bank collapse was divided into three levels. After the establishment of this method, it was applied in the riverbank stability evaluation in typical engineering dangerous section of Jingjiang River. Results show that the risk level of bank collapse can well predict the actual these factors, current study on riverbank stability is still far from meeting the demand of quantitative evaluation. Therefore, it is urgent to establish an applicable and operable assessment method for riverbank stability, thus to improve the predictability of bank collapse. In this study, firstly, according to the current situation, influencing factors and development process of riverbank stability, range of bank collapse, and the evaluation method of riverbank stability is basically reliable. This study is helpful to improve the ability of bank collapse defense and watershed management.