某河流穿越管道爆裂失效事故分析

针对某长输天然气管道河流穿越管段爆裂失效事故,通过断口形貌、无损检测、化学成分、微观组织、力学性能分析以及有限元模拟计算等方法,进行事故原因分析.结果表明：该管段在穿越施工空管回拖过程中因承受某种集中载荷作用而使管体局部受力发生形变,产生局部屈曲失稳;该失稳管段在输气运行过程中,屈曲形变部位存在明显的应力集中,导致管体外壁形变硬化处的微裂纹扩展并失效.因此,管体失稳至裂纹扩展及防腐层破裂是管体泄漏失效爆裂的主要原因.（表4,图13,参15）

Analysis on burst failure of a river crossing pipeline

Aiming at the burst failure of a long-distance river crossing gas pipeline, the causes of the accident are analyzed by fracture morphology, nondestructive testing, chemical composition, microtexture, mechanical performance analysis and finite element simulation. The results show that the pipeline segment was stressed a concentrated load in the process of backtow with blank pipe during river crossing, which led to pipeline deformation under local stress, finally partial buckling. There was a significant stress concentration at the buckled deformation part during gas delivery of the unstable gas pipeline, leading to the extension of micro-cracks from deformation hardening at the outer wall and the failure of the pipeline at last. Therefore, crack extension and anticorrosion coating break caused by instability of the pipeline is the main reason behind the burst failure of the pipeline. （4 Tables, 13 Figures, 15 References）