冲积河流岸滩崩退模式与崩退速率

为研究冲积河流的侧向演变过程并开展模拟预测,采用河道冲刷及河岸稳定性等理论探讨岸滩的崩退模式和崩退速率。根据河岸崩塌机理及崩体塌落到水中后冲刷形式的不同,提出3种岸滩崩退模式,分别为挫崩滑塌冲刷崩退模式、挫崩倒塌冲刷崩退模式和落崩冲刷崩退模式。结合河岸的侧向淘刷、河床的纵向冲刷以及河岸崩塌的临界状态,推导了3种岸滩崩退模式的崩退速率计算公式,并利用长江和黄河的水文、河岸资料进行检验。结果表明:长江和黄河的河岸岸滩崩退速率估算值与实际崩退速率基本相符,所建立的岸滩崩退模式和崩退速率计算公式是合理的。

Study on collapse-retreat patterns and bank erosion rates of alluvial riverbanks

To intensively study and predict the lateral evolution of alluvial rivers, the theories of riverbank erosion and stability are used to discuss the patterns and the rates of riverbank collapse-retreat in this paper. Based on the mechanism of the riverbank collapse-retreat, three types of analysis models are proposed, which are the sinking-slipping failure, the sinking-toppling failure and the falling failure. Combined with the lateral erosion of river banks, the longitudinal scour of river bed and the critical condition of bank failure, the formula of bank erosion rates is derived. The hydrological data and soil properties of the Yellow River and the Yangtze River were used to validate the proposed formula. The results show that the estimated retreat distance and erosion rates are in consistent with the actual erosion rates of the Yellow River and the Yangtze River, indicating that the proposed collapse-retreat patterns and the formula of bank erosion rates are reasonable.