管道最大腐蚀坑深的极值统计方法研究

极值统计方法的原理是:对最大值或最小值数据进行极值统计,构造实际问题的统计分析模型,采用统计方法推断获得最大极值或最小极值的估计值,作为评价或预测评估的依据。长输管道的腐蚀类型多为均匀腐蚀或点腐蚀,采用极值统计方法对在役管道的点蚀尺寸进行预测,进而评价管道的剩余强度,对于控制管道的腐蚀穿孔事故、指导管道的修复更换、延长管道的使用寿命具有重要意义。文章讨论了管道最深点蚀孔深度的统计规律以及局部腐蚀深度最大极值估计值的确定方法,并给出了实际算例。分析结果表明,这一方法可用于在役管道缺陷尺寸的预测。

Study on Extremum Statistical Method of Maximum Corroded Pit Depth of Pipeline

The corrosive patterns of long distance pipeline are mostly sorted to be uniform corrosion and pit corrosion. Using extremum statistical method to predict pit corrosion sizes of the pipeline in service and further to evaluate the residual strength of the pipeline has a great significance for controlling accidents of corrosive perforations, guiding pipeline rehabilitation and replacement as well as prolonging service life of pipeline. This paper discusses the statistical rule of maximum corrosive pit depth and determination method of extremum estimation for local corrosion depth, and presents a practical example of calculation. The analytical results show that this method can be applied in defect size prediction of pipeline in service.