基于可能性理论的埋地管道腐蚀失效预测

Corrosion Failure Prediction of Buried Pipes Based on Possibility Theory

埋地管道在外部荷载和腐蚀联合作用下,随着服役时间的增长而失效风险增大。通过建立管道受力模型,并对参数进行模糊化处理,给出了运用模糊运算算法对管道失效不确定性进行系统分析的方法,同时运用可能性理论对管道失效风险进行可能性和必要性双参数测量。结果表明:影响管道安全性的主要因素有管道内压、壁厚、管壁腐蚀、残余应力等。管道失效风险随内压、残余应力均值和变异性的增加而增大,尤其是管道的失效可能性迅速增大。腐蚀导致管道壁厚减薄,从而导致管道承载力下降。土体环境对管道的腐蚀在经过使用初期的积累后成为管道失效的主要因素,因此腐蚀保护是延长管道寿命非常有利的措施。

The failure risk of buried pipes increases with service time under the combined effect of soil corrosion and external loads. A model for pipe stress was built, and the parameters were processed u- sing fuzzy sets. The method for analyzing the uncertainty of pipe failure by fuzzy algorithm was presented. Possibility and necessity of buried pipes failure were measured using possibility theory. The results showed that the main factors affecting pipe safety included inner pressure, wall thickness, wall corrosion, residual stress and so on. The failure risk increased rapidly with increase in mean values of inner pressure and residual stress as well as variability. The corrosion could reduce the wall thickness, and thus the pipe bearing force. The soil corrosion of buried pipes was one of the most important factors contributing to the pipe failure. The application of corrosion control technique was the most effective way to extend the pipe service life.