随着我国经济社会建设的快速发展,部分在役天然气管道所通过的地区逐渐由过去人口稀少的一级、二级地区升级为人口密集的三级、四级地区,管道失效的风险大幅度增加,急需建立相应的定量风险评价技术以确定管道的实际风险水平.为此,提出了基于可靠性的天然气管道定量风险评价流程:首先采用基于可靠性的极限状态方法计算评价管段的失效概率、采用管道失效后果模型计算管道的失效风险,并依据计算结果对地区等级升级后的天然气管道进行定量风险评价;然后引入风险可接受准则,判定地区等级升级后天然气管道的个体风险水平和社会风险水平;进而有针对性地制订风险消减、防护措施.实际应用结果表明:该技术不仅可以实现天然气管道失效风险的定量计算和评价,而且还能够对不同风险消减、防护措施进行效果检查及对比,在保障天然气管道风险可接受的前提下,实现天然气管道风险控制管理技术性和经济性的最优化.%With the fast development of social and economic construction in China,the areas through which some in-service gas pipelines run are gradually upgraded from Class 1 and 2 areas of sparse population to Class 3 and 4 areas of dense population,so the failure risk of pipelines is increased significantly.Thus,it is necessary to develop the corresponding quantitative risk assessment technology so as to determine the actual risk level of pipelines.In this paper,the reliability-based quantitative risk assessment process for natural gas pipelines was put forward.Firstly,calculate the failure probability by means of the reliability-based ultimate limit state,calculate the pipeline failure risk by using the pipeline failure consequence model,and conduct quantitative risk assessment on the natural gas pipelines in the upgraded areas according to the calculation results.Secondly,introduce the risk acceptance criteria to discriminate individual risk and social risk levels of natural gas pipelines after location class upgrading.And thirdly,formulate risk reduction and control measures correspondingly.The actual application results indicate that by virtue of this technology,not only can the failure risk of natural gas pipelines be calculated and evaluated quantitatively,but the effects of risk reduction and control measures can be checked and compared.And thus,the gas pipeline risk control and management technology is technically and economically optimized while the gas pipeline risk is kept in an acceptable range.
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