水下穿越管道可变荷载的统计分析

Statistic analysis of variable load on underwater crossing pipeline

基于水下穿越管道所受可变荷载的随机性,采用平稳二项随机过程作为可变荷载的概率模型,并利用该模型的基本特性,得出了设计基准期内可变荷载最大值的概率分布函数F_M(x)与任意时点概率分布函数F(x)之间的实用关系式。对于裸露悬空水下穿越管道承受的动水荷载,采用相关模型理论计算管道的动力响应幅值,进而求出管道所受的动应力,最后根据水下穿越管道服役期内的荷载状况将其划分为空管状态、正常运行状态、裸露悬空状态等三个服役阶段,并针对这三种状态的管道分别进行荷载效应组合。上述可变荷载统计分析方法符合在役水下穿越管道可变荷载的实际情况,其结果可作为水下穿越管道可靠性分析与设计的参考。

Based on a randomness of variable load on underwater crossing pipeline, using stable binomial random process as a probability model of variable load and by means of a basic characteristic of the model, obtains an applicable relational expression between probability distribution function FM(X) of maximum variable load value within design base period and probability distribution function F(x) of random point. As for the dynamic water load on underwater crossing pipeline naked and suspended, relative model theory is used to calculate pipeline's dynamic response extent value, thus obtains the dynamic stress on pipeline, and finally divides the pipeline into such three service stages as empty pipeline statue, normal operation statue and naked and suspended statue according to load statue in pipeline's service span, and makes a load effective combination of pipelines with the three statues. This statistic analysis method for variable load conforms to real situation of variable load on service underwater crossing pipeline and its result offers an reference to underwater crossing pipeline's reliability analysis and design.