随着我国城市燃气化步伐的加快,许多大中城市都发展了管道燃气工程,其燃气输配管网分布于城市绝大部分街道和居民庭院。终端已延伸到了千家万户、工厂的车间、餐饮服务的灶间和锅炉房。受到多方面因素的制约,城市燃气输配系统的泄漏事故还时有发生。尽管每个城市的燃气输配系统的煤气泄漏事故不是多发的,但每次泄漏事故都会造成不同程度的经济损失和人员伤亡,而且还会产生不良的社会影响。对于一个城市,特别是对大城市和历史悠久的城市而言,其地下构筑物——热力设施、给排水设施、供配电设施、电信设施等,往往沟槽纵横交错,而煤气输配管网多是在这些设施之后敷设的,与原有的地下构筑物相互交叉时,往往采取不同的方式 As the pace of gasification in cities in our country accelerates, many large and medium-sized cities have developed pipeline gas projects, and their gas transmission and distribution networks are located in most urban streets and residential courtyards. Terminal has extended to millions of households, the factory workshop, food service and boiler room. Subject to many factors, the leakage accident of the urban gas transmission and distribution system also occurs from time to time. Although gas leaks in gas transmission and distribution systems are not frequent in each city, each spill will cause varying degrees of economic loss and casualties as well as adverse social impacts. For a city, especially for big cities and historic cities, its underground structures - thermal facilities, water supply and drainage facilities, power distribution facilities, telecommunications facilities, often criss-cross the trenches, while the gas transmission and distribution network Most of them are laid after these facilities and often adopt different ways when they intersect with the original underground structures