The ventilation system is the only channel for gas exchange inside and outside the gas tunnel. Therefore, it is very important to evaluate its reliability for the safe operation of the gas tunnel. In this paper, the ventilation system of gas tunnel in Songjiang District of Shanghai City is taken as the study object, a fault tree model of the ventilation system is established, and a corresponding evaluation model of Bayesian network is formed according to the mapping rule. The fuzzy probability obtained from the fuzzy set theory and the multi-layer expert judgment is taken as the prior probability, the reliability evaluation of the ventilation system was carried out. Finally, the hierarchical management measures of the ventilation system are formulated. The results are as follows: (1) The main risk sources of the ventilation system include the third party damage, system aging, design defect and misoperation. (2) The aging of exhaust fan and no emergency and alarm function seriously reduce the reliability of the ventilation system. (3) The events with high sensitivity and promoted index to the failure of the ventilation system are completely consistent and concentrated on the system aging and design defect. (4) The aging of lines, exhaust fan and alarm instruments are the most likely evolution paths of the failure of the ventilation system. (5) At present, the reliability level for the ventilation system of gas tunnel in Songjiang District of Shanghai City is level IV, and it can run safely.

通风系统是在瓦斯隧道内外进行气体交换的唯一通道。因此，评估其可靠性对于燃气隧道的安全运行非常重要。本文以上海市松江区煤气隧道通风系统为研究对象，建立了通风系统的故障树模型，并根据映射规则建立了相应的贝叶斯网络评价模型。从模糊集理论和多层专家判断中获得的模糊概率作为先验概率，对通风系统进行了可靠性评估。最后，制定了通风系统的分级管理措施。结果如下：（1）通风系统的主要风险来源包括第三方损坏，系统老化，设计缺陷和误操作。（2）排风扇老化，无紧急报警功能，严重降低了通风系统的可靠性。（3）对通风系统故障的敏感性高，指标提高的事件是完全一致的，并且集中在系统老化和设计缺陷上。（4）管道，排气扇和警报器的老化是通风系统故障的最可能演变途径。（5）目前，上海市松江区煤气隧道通风系统的可靠性等级为IV级，可以安全运行。（2）排风扇老化，无紧急报警功能，严重降低了通风系统的可靠性。（3）对通风系统故障的敏感性高，指标提高的事件是完全一致的，并且集中在系统老化和设计缺陷上。（4）管道，排气扇和警报器的老化是通风系统故障的最可能演变途径。（5）目前，上海市松江区煤气隧道通风系统的可靠性等级为IV级，可以安全运行。（2）排风扇老化，无紧急报警功能，严重降低了通风系统的可靠性。（3）对通风系统故障的敏感性高，指标提高的事件是完全一致的，并且集中在系统老化和设计缺陷上。（4）管道，排气扇和警报器的老化是通风系统故障的最可能演变路径。（5）目前，上海市松江区煤气隧道通风系统的可靠性等级为IV级，可以安全运行。排气扇和警报器是通风系统故障的最可能演变途径。（5）目前，上海市松江区煤气隧道通风系统的可靠性等级为IV级，可以安全运行。排气扇和警报器是通风系统故障的最可能演变途径。（5）目前，上海市松江区煤气隧道通风系统的可靠性等级为IV级，可以安全运行。