中文摘要：

利用尖点突变模式开展北港稳定性判别及定量研究,分析河口河势稳定性指标,选择断面宽深比作为河势变化的第一主控变量,为横向稳定性指标;河槽冲淤量作为河势变化的第二主控变量,为纵向稳定性指标,对北港河势进行评价及验证。结果表明：尖点突变模式可以较好地评估北港河势稳定性,北港主槽堡镇-团结沙河段1977-1992年间河势不稳定,之后河势基本趋于稳定;团结沙-口外拦门沙河段1977-2010年间河势基本稳定,2010-2013年不稳定。

英文摘要：

Stability evaluation of North Channel in the Yangtze estuary was conducted by a cusp catastrophe model. River regime stability index was discussed. The width depth ratio for the river regime change is selected as the first main control variables,which is lateral stability index. To evaluation and verify the river regime of North Channel of the Yangtze estuary stability,the scour and silting amount for the river regime change as the second main control variables,which is longitudinal stability index. Results show that the cusp catastrophe model can better evaluate stability for North Channel of the Yangtze estuary. Regime is instable between Baozhen and Tuanjiesha in the North Channel from 1977 to 1992,and tends to be stable later. Regime is stable between Tuanjiesha and offshore of North Channel from 1977 to 2010,and it is instable between 2010 and 2013.