考虑腐蚀的城市燃气管网抗震可靠度分析

基于马尔可夫过程原理提出了管线腐蚀发生模型,结合线性腐蚀发展模型,获得了埋地管线截面面积的概率密度函数。在此基础上,利用弹性地基梁原理给出了管线在地震作用下的地震反应,采用随机摄动方法给出了腐蚀管线地震反应的均值和标准差。根据规范公式建立了地震下管线极限状态方程,进而获得管线抗震可靠度。利用改进最小路递推分解算法进行了管网的抗震可靠度分析。该算法以网络最小路为分解策略,利用布尔运算原理给出了网络的递推分解格式,可以同时获得管网的不交最小路和不交最小割,进而利用概率不等式给出满足工程精度的结果。利用上述方法对一个工程实例进行了抗震可靠度分析。

Seismic Response Analysis of Urban Gas Networks Considering Corrosion

In this paper,Markov process was used to simulate the occurrence of corrosion on the pipeline.Combining with linear corrosion development model with deterministic corrosion rate parameters,the evolution of probability density function of corrosion ratio of pipeline section area as service time increases was derived.On the basis of above corrosion model,elastic foundation beam model was used to give the pipeline stress.Then using random perturbation approach,the random seismic response of pipeline is derived.A limit state equation is established based on code and pipeline seismic reliability can be obtained.Also,a path-based recursive decomposition algorithm is presented to calculate seismic reliability of lifeline networks.The algorithm takes the shortest path of network as decomposition policy,using the Boolean laws of set operation and the probabilistic operation principal,the disjoint minimal path set and the disjoint minimal cut set are enumerated simultaneously.As the result,a probabilistic inequality can be used to give the results that satisfy prescribed error bound.An actual network is calculated using the proposed approaches.