【摘要】 三峡水库蓄水后下荆江河段河床持续冲刷,局部河段崩岸险情时有发生,研究下荆江二元结构河岸的崩退过程,有利于全面掌握该河段的演变规律。以下荆江荆98断面为研究对象,结合实测水文资料及断面地形资料,应用BSTEM模型计算了该断面右侧河岸2007及2010年的崩退过程,同时分析了弯道二次流及岸顶植被对崩岸过程的影响。结果表明:下荆江二元结构河岸的崩岸一般多发生在洪水期和退水期,其中洪水期为崩岸强烈阶段,退水期为崩岸较强阶段;弯道二次流的影响使得河岸坡脚冲刷更为严重,不利于凹岸的稳定性;岸顶植被增强了上部黏性土层的抗剪强度,有利于河岸的稳定性。更多还原

【Abstract】 Channel degradation and the phenomenon of bank erosion are occurring frequently along the Lower Jingjiang Reach after the operation of Three Gorges Project. In order to better understand the fluvial processes in the Lower Jingjiang Reach,it is necessary to investigate the failure process of composite bank. Based on the hydrological data and the observed cross-sectional profiles,the bank erosion processes of the right riverbank at the Jing98 section during the 2007 and 2010 hydrological years were simulated using BSTEM. The effects of secondary flows and vegetation rooting were also investigated. Simulated results indicate that the degrees of riverbank stability were low during the flood season and the recession stage,which are the stages of more intensive and intensive bank failure,respectively; the process of bank-toe scour was relatively severe due to the effect of secondary flows,which can cause the concave bank to become unstable. The vegetation enhanced the soil shear strength of the cohesive upper bank,which is effective in increasing the bank stability.更多还原