燃气管道失效概率评估方法研究

失效概率评估是燃气管道定量风险评估的关键内容之一。对基于专家估计的主观失效可能性评估方法和基于历史失效数据统计或强度理论的客观失效概率评估方法的优缺点进行了分析,提出了一种主观方法和客观方法相结合的失效概率评估方法。采用历史失效数据统计方法,计算燃气管道的平均失效概率;采用层次分析法,利用专家估计数据,求得管道失效可能性,并认为主观估计的中等可能性等于历史失效数据统计的平均失效概率,从而确定主观失效可能性和客观失效概率之间的关系式。以埋地钢质管道腐蚀失效为例,阐述了这种失效概率评估方法。采用主观估计法,求得任意情况下的管道失效可能性,利用主观可能性和客观概率之间的关系式,求出燃气管道的客观失效概率。

Assessment methods of failure probability on gas pipelines

The failure probability assessment (FPA) is one of the key quantitative risk assessments on gas pipes. The present paper analyzed both advantages and disadvantages of the subjective FPA method based on experts experience and the objective FPA method based on historical failure data or intensity theory, respectively. A new assessment method combined by the both subjective and objective methods was developed in this paper, and it adopted a statistic analysis on historical failure data to calculate an average failure probability of gas pipes and applied a hierarchy analysis on experts evaluation data to figure out a failure possibility of gas pipes. A relationship between the subjective failure possibility and objective failure probability was built up through this integrated analysis method that assumes the medium possibility of the subjective assessment equal to the average failure probability of the historical failure data. Taking the failure probability by corrosion on buried steel pipelines as an example, the paper expatiated upon this approach of the failure probability assessment, which firstly estimated the failure possibility of pipelines under any conditions via the subjective assessment, and then determined the objective failure probability of pipelines by means of the relationship between the subjective possibility and objective probability.