埋地管线均匀腐蚀失效力学模型及随机分析  

Mechanical model and probability analysis of buried pipelines failure under uniform corrosion

作　　者：邵煜[1] 虞介泽[1] 俞亭超[1] 

机构地区：[1]浙江大学土木工程学系,浙江杭州310058

出　　处：《浙江大学学报（工学版）》2010年第6期1225-1230,共6页Journal of Zhejiang University：Engineering Science

基　　金：国家水体污染控制与治理科技重大专项经费资助项目(2008ZX07425-008);国家自然科学基金资助项目(50708091);中国博士后科学基金资助项目(20090461383)

摘　　要：针对埋地管线在外部荷载和腐蚀联合作用下导致的失效问题,综合考虑埋地管线纵向和环向受力特性、腐蚀规律,建立失效预测模型,在此基础上运用一次二阶矩法(FOSM)对模型和参数的不确定性进行随机模拟,并对影响管道失效的主要参数如内压、残余应力、腐蚀参数等进行敏感性分析.结果表明:一次二阶矩(FOSM)与蒙特卡罗法(MC)计算结果基本符合,采用FOSM计算埋地管线的腐蚀失效概率是可行的;内压和残余应力的均值、变异系数越大,管道失效概率越大;残余应力随着腐蚀的发展逐步释放,在管道使用后期对失效的影响减小;管道失效概率在使用10～20a内增长迅速,之后由于腐蚀的自我抑制作用增长缓慢.内压、残余应力、壁厚、屈服强度和腐蚀是影响管道失效的5个重要因素,其中腐蚀尤为重要,减缓腐蚀速度的管道防腐技术可以有效减少管道的失效概率,延长管道使用寿命.To resolve the failure problems for the buried oil and gas pipelines under the combined effect of soil corrosion and complex stress induced by external loads,a failure prediction model was developed by combining longitudinal and circumferential mechanical characteristics of pipes with the corrosion model. First order second moment （FOSM） was used to perform the probabilistic analysis,taking the uncertainty of the model and parameters into consideration. Then the sensitivity analysis of the important parameters such as inner pressure,residual stresses and corrosion parameters were given. Results showed that it was suitable to adopting the FOSM to calculate the failure probability,because the value by the FOSM agreed well with the one by the Monte-Carlo method（MC）. The reliability decreased with the increased mean values and variances of the inner pressure and residual stresses. The residual stresses,which were released with corrosion,had smaller influence on the pipe failure in the late stage. The failure probability of pipes increased fast when used 10-20 years,but slowed down after then because of the self inhibition of corrosion process. The inner pressure,residual stresses,pipe thickness and corrosion parameters have large influence on the failure probability for the buried oil and gas pipes. The corrosion is one of the most important factors contributing to the pipe failure. Reducing corrosion pit depth growth by using the corrosion control technique can be the most effective way to decelerate the breakage growth rate and extend the service life.

关 键 词：埋地管线 腐蚀失效 一次二阶矩法 可靠度 敏感性分析 

分 类 号：TE973.1[石油与天然气工程—石油机械设备] TB114.3[理学—概率论与数理统计]