中文摘要：

根据长江中下游河段大量的崩岸实例,提出规模较大出现几率最高的是两种渐进式崩岸,即坍塌型崩岸和流滑型崩岸,并分析了两种渐进式崩岸的基本特征和力学性质,包括岸坡崩塌的表现形式、影响因素、成因和力学机理及分布规律等。结果表明,两种渐进式崩岸虽然貌似相同,但实质上有很大区别,坍塌型崩岸为高大陡坡中由渗流引起的土体崩塌破坏,流滑型崩岸则是水流冲刷过程中引起的土体滑落破坏。

英文摘要：

Based on the analysis of many bank caving cases in the middle and lower reaches of the Yangtze River, two kinds of gradual bank caving, occurring most frequently with very big failure extent, are presented and discussed. Then,their basic characteristics and cause,including expression shape of failure, aeffecting fac- tors,formation process and distribution law,are analyzed completely from views of river dynamics and soil me- chanics. The result shows that two types of caving are similar seemingly but different substantially. The decli- ning collapse occurring at a high steep slope is a soil block failure caused by seepage and the sliding collapse is a soil block failure caused by strong scouring.