建筑物占压作用下输气管道的安全可靠性评估

Safety and reliability assessment of gas pipelines under building occupation

城市建筑物对管道的占压较普遍,易导致地基下沉、管道变形,并可能诱发油气介质泄漏,甚至引发爆炸事故。在此,建立了基于应力-强度干涉的管道可靠性模型,在结构可靠度理论基础上,分析了建筑物占压作用下占压附加应力、管道危险截面的最大折算应力以及管材屈服强度3个随机参数的分布情况;为达到当量正态化,依据经典的JC算法,处理非正态分布变量,基于结构线性功能函数,设定未知量的迭代初始值,以提高算法的收敛速度及精度;建立了基于M-JC算法的框架结构建筑物和砖混结构建筑物两类现场占压作用下的输气管道可靠性模型,并结合Matlab软件实现M-JC算法改进,对占压管段的可靠性进行分析。结果表明:框架结构建筑物占压管段与砖混结构建筑物占压管段的可靠度分别为0.985 2和0.999 8,可见地面覆土荷载对完好管道的影响不大;M-JC算法与JC算法的结果误差很小,相对误差在1%以内。研究结果适用于分析建筑物占压管道的可靠性,对管道安全运行、城市建设规划具有参考意义。

Building occupation is common for pipelines in urban area, which likely leads to the subsidence of foundations and deformation of pipelines and induces accidents such as oil and gas leakage, even explosions. In this study, a pipeline reliability model based on stress-strength interference was established. Meanwhile, the distribution of three random parameters under building occupation, including the additional stress under building occupation, the maximum reduced stress of dangerous pipeline sections and the pipe yield strength, were analyzed based on the theory of structural reliability.In order to achieve equivalent normalization, the variables in abnormal distribution were processed according to the classic JC algorithm, and the iterative initial value of the unknown was set based on the structural linearity performance functions to improve the convergence speed and precision of the algorithm. In addition, a reliability model of gas pipeline under the occupation of framed and brick-concrete buildings based on M-JC algorithm was established, and the reliability of the occupied pipeline was analyzed by implementing the M-JC algorithm in combination with Matlab programming. As shown by the results, the reliability of pipeline sections under the occupation of the framed and brick-concrete buildings is 0.985 2and 0.999 8, respectively, indicating that the surface overburden load has little effect on the undamaged pipeline. In addition,the error between the results of M-JC algorithm and JC algorithm is very small, with a relative error less than 1%. Generally,the research results are applicable to the analysis on reliability of pipeline under building occupation and have reference value to the safe operation of pipelines and the urban construction planning.(9 Figures, 2 Tables, 23 References)