近年来油气管道通过环境敏感区的问题日益突显,对于环境敏感区的油气管道过江隧道而言,隧道两端的连接管道及隧道本体与环境敏感点的安全间距、河床段隧道的合理埋深是关乎油气管道能否安全通过环境敏感区的关键。因此,环境敏感区油气管道过江隧道合理合规的设计，对于保障工程的建设与运行安全均具有重要意义。以浙江省天然气管网“县县通”工程大溪隧道为例,依据相关的法律法规、标准规范及工程惯例,全面分析了连接管道及隧道本体与各类环境敏感点的安全间距和以指标控制的安全评价方法;采用国内外常用的经验法和数值分析法,结合河床段的水文地质条件,确定了大溪隧道在河床段的合理埋深。分析结果表明,大溪隧道平面穿越轴线和纵断面穿越地层设计合理,确保了施工和运行的安全，节约了工程投资。研究结果可为类似环境敏感区油气管道过江隧道设计提供参考。

 In recent years, the problem of oil and gas pipelines passing through environmentally sensitive areas has become increasingly prominent. For oil and gas pipelines river-crossing tunnels in environmentally sensitive areas, the safety distance between the connecting pipelines at both ends of the tunnel and the environmental sensitive points, the safety distance between the tunnel and the environmental sensitive points, and the reasonable buried depth of the tunnel in the river bed are the key points to decide whether the oil and gas pipeline can safely pass through the environmentally sensitive area. Therefore, the reasonable and compliant design of river-crossing tunnels for oil and gas pipelines in environmentally sensitive areas is of great significance for ensuring the safety of project construction and operation. This paper takes the Daxi tunnel of Zhejiang‘s “county-county access” project as a study example. According to relevant laws, regulations, standards, and engineering practices, the safety distances between connecting pipelines and tunnels and various environmental sensitive points are comprehensively analyzed, and the safety assessment based on safety indicator control is adopted. Using engineering experience, numerical analysis, and theoretical calculation methods commonly used at home and abroad, and combined with the hydrogeological conditions of the riverbed section, the reasonable buried depth of the riverbed section of the Daxi Tunnel is determined. The results show that the design of plane crossing axis and longitudinal section crossing stratum of Daxi tunnel is reasonable, as it ensures the safety of construction and operation, and saves project investment. This research results can provide reference for the design of oil and gas pipeline river-crossing tunnels in similar environmentally sensitive areas.