天然气管道滑移失效分析

Failure Analysis on Natural Gas Pipeline Slip

广东某天然气管道由于附近施工基坑坍塌,地下淤泥层流动导致滑移变形,滑移段长度65 m,明显变形段长度35m,水平滑移0.7m,在对变形处管道实施了去应力卸载后,进行了变形测量,焊缝无损检测,受力计算,有限元分析和安全评估等工作。计算发现滑移产生的轴向应力大于管道所处4级地区允许的最大轴向许用应力,建议释放管道外在应力,使其回弹后继续服役,并对管道两侧采取桩基础固定处理,提高安全裕量。

A natural gas pipeline foundation pit collapsed due to the nearby construction somewhere in Guangdong, and the underground silt layer flow leads to the pipe slip deformation. The slip length is 65 m, the significant deformation length is 35 m, and the horizontal deformation is 0.7 m. After the deformed part unloaded and distressed, the deformation measurement, nondestructive examination of welds, stress calculation, finite element analysis and safety assessment were conducted. The calculating results show that the maximum axial stress caused by slip is larger than the allowed stress of the pipe at 4th level area. It is suggested that the rebound pipe continue its service after external stress release, and the pile foundation should be fixed on the two sides to improve the safety allowance.