一起埋地聚乙烯燃气管道泄漏事故原因分析

Analysis of a Leakage Accident of Buried Polyethylene Gas Pipeline

埋地中压聚乙烯燃气管道电熔接头发生泄漏事故.针对该事故展开技术分析和调查,在充分调查事故基本情况、燃气管道技术参数的基础上,通过对含缺陷电熔接头进行相控阵超声检测、拉伸剥离试验,分析相控阵图谱及拉伸断口形貌并得出结论.结果表明:电熔焊接接头内部存在未熔合缺陷,未熔合缺陷面积在整个焊接接头中占比较大,局部区域长期在低剪应力载荷作用下发生结构变形,实际承载面积严重收缩,最终开裂泄漏;安装期间未进行焊接接头检测,聚乙烯燃气管道监管单位未进行监督检验是引发该事故发生的间接原因.最后,笔者提出了预防此类事故发生的方法和措施.

A leakage accident occurred in the electric fusion joint of a buried medium pressure polyethylene gas pipeline.Based on the basic situation of the accident and the technical parameters of the gas pipeline,the failure analysis was carried out by phased array ultrasonic testing of the electric fusion joint containing defects and fracture morphology inspection of tensile peel test.The results show that:there are incomplete fusion defects in the electric fusion welding joint,and the area of the incomplete fusion defect accounts for a large proportion of the whole joint.The direct cause of the leakage is the creep fracture under the long-term tensile force;the indirect cause of the accident is that the welding joint detection is not carried out during the installation,and the supervision and inspection of the polyethylene gas pipeline supervision unit is not carried out.At the end of the article,the author puts forward the methods and measures to prevent such accidents.