Author(s): Zhu Yonghui; Deng Caiyun; Li Lingyun
Linked Author(s):
Keywords: Bank collapse; Riverbank stability; Investigation; Influencing factors; The middle and lower reaches of the Yangtze River
Abstract: The middle and lower reaches of the Yangtze River traverse a vast alluvial plain, vulnerable to erosion, resulting in frequent bank collapses, which could seriously affect the sustainable development of the local economy and society. From 2003 to 2022, a total of 1049 bank collapses occurred in the middle and lower reaches of the Yangtze River, spanning over 758.7 km in cumulative length. Although there has been a recent decline in bank collapses due to the ongoing riverbank protection projects, bank collapses still occur occasionally even in protected banks because of a complex array of influencing factors, including near-shore water-sediment dynamics, internal seepage processes within the riverbanks, alterations in soil properties, etc. Analysis results indicate that influencing factors contributing to bank collapses in the middle and lower reaches of the Yangtze River have significantly changed in recent years. Firstly, the continuous erosion of the river channel, particularly the near-shore bed leads to increased height differences between the riverbed and the banks thereby elevating potential for bank slope instability. Secondly, the adjustment of local river regimes causes shifts in flow rushing points and changes in extent of mainstream adjacency to the banks, which can lead to erosion and caving along inadequately safeguarded riverbanks. Thirdly, during post-flood water-fall periods when water levels rapidly decrease, infiltration pressure negatively impacts bank slope stability. Additionally, during pre-flood water-rise periods when flow velocity sharply increase, bank collapses are prone to occur due to intensified scouring caused by high-flow conditions.
Year: 2024