某输油管道凹陷适用性评价及修复建议

Fitness for Service Assessment and Repair Suggestion of Dents on Oil Pipeline

某输油管道智能测径发现4处深度大于6%管径的凹陷。通过记录凹陷回弹前后深度差异,发现回弹后深度平均是回弹前的69.1%。根据不同标准对4处凹陷进行了基于深度和基于应变的评价,发现2处凹陷需要修复。但剖析国外某管道凹陷泄漏案例后,发现即使符合标准要求无需修复的浅凹陷,也可能因为形状特殊形成较大应力集中,从而发生疲劳失效。因此又对凹陷修复方法进行了分析,发现现有标准缺乏凹陷损失强度的计算方法,因此无法准确设计复合材料或环氧套筒修复的厚度和宽度。建议4处凹陷采取3处加装B型套筒和1处换管的修复措施。

4 dents with a depth greater than 6%D were found by intelligent caliper in an oil pipeline.By recording the depth before and after dent rerounding,it is found dent depth after rerounding is 69.1%of that before rerounding.Fitness for service assessment of 4 dents were conducted according to different standards,and it is found that two of them needed repairing.But a foreign dent failure case shows that even if shallow dent which does not need to repair,it may form a large stress concentration due to its special shape,and has a fatigue failure.So repair methods of dent were also studied.It is found that existing standards lack calculation method of strength loss of dent,so it is impossible to design the thickness and width of composite material sleeve or epoxy sleeve accurately.Therefore,it is recommended to install type B sleeve for 3 dents and replace pipe for 1 dent.