中文摘要：

洪水冲刷是影响输油悬空管道稳定性的重要灾害之一。对洪水冲刷输油悬空管道进行受力分析可知，漂浮管道易产生拉弯变形。为此，建立了水冲管道力学分析模型，应用基于应变准则的失效判据关系式来判断管道的安全状态，并用有限元软件ABAQUS对X60输油管道在一定洪水流速和一定悬空长度2种工况下的安全状态进行模拟与分析。分析结果表明，最大应力、应变及挠度与悬空长度成正相关关系；一定悬空长度下，最大应力、应变及挠度与洪水流速成正相关关系，且当流速大于3m／s时，管道的振动频率升高，加大管道失效可能性。水冲悬空管道的危险点位于埋设段与悬空段交汇处的水流入侧。

英文摘要：

Flood scouring is a key factor that may present severe threat to stability of suspended pipe- lines. Results of force analyses for suspended pipelines under flood scouring show that floating pipelines are suscep- tible to bending deformation. Mechanical analysis model for pipelines with flood scour is established. In addition, strain criteria are used to determine safety conditions of the pipeline. A finite element software, ABAQUS, is used for simulating and analyzing safety conditions of X60 oil pipelines at certain flood velocity and certain suspended length. Test results show that maximum stress, strain and deflection have positive correlation with the suspended length. Moreover, under specific suspended length, maximum stress, strain and deflection have positive correla- tion with flood velocity. With flow velocities higher than 3 m/s, pipelines may have vibration frequencies increased together with possibilities of failure. The point with highest danger of suspended pipeline under flood scouring locates at the jointing section between buried interval and the suspended interval on the side with water inflow.