埋地钢质管道外涂层缺陷的安全质量分级评价

针对目前国内尚无一套完整的关于管道外涂层（尤其是外涂层缺陷）分级评价方法的现状，分析了国外分级标准的适用性和分级指标的合理性，指出其存在的问题，经过系统分析和比较，提出了更切合我国实际的分级评价指标制定思路。重点研究了 ACVG 的检测原理，建立了 ACVG 缺陷电场模型，提出电平差值、辐射距离和近似电场能 3 个分级评价指标。根据大量现场开挖和数据统计分析，提出了具有广泛适用性的外涂层缺陷安全质量分级评价准则。按照制定的 ACVG 分级评价准则，进行了现场应用试验，现场间接检测结果与直接检测结果符合率达到 88.24 %，由此证明该分级评价准则是较为准确、可行的。通过对管道外涂层缺陷进行合理的安全质量分级，管道管理者可按照不同级别确定相应的安全运行维护策略，提高管道维修的针对性与工作效率。
　

The evaluation method on pipeline external coating grading especially the defects of external coating in China has not been established. Aiming at this situation，the applicability and grading index reasonability in grading standards from other countries are analyzed in the paper. The analysis results reflect the differences existed in the grading standards，and based on systematic comparison，the grading evaluation indices which are more practical to application in China are proposed. Through putting the emphasis on the ACVG inspection principle and establishing the ACVG defect electrical field model，three indices in current level difference，radiation distance and approximated electrical field energy are put forward. Based on large scope field excavation and statistics study，the applicable external coating defect grading evaluation regulation is provided. According to the regulation，the field investigation is carried out. Results show that the result similarity reaches 88.24% for indirect and direct inspection， proving the accuracy and applicability of the grading evaluation regulation. By the grading，pipeline operator can make corresponding strategy to enhance the pipeline repair efficiency and pertinence according to different grades.

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