为解决公路隧道通风斜井取消二次衬砌对洞室稳定性和通风造成影响的问题，根据秦岭天台山隧道1#斜井Ⅲ级围岩段的地层特点和施工情况，从规范符合性、结构的安全性和耐久性等方面入手，分析取消二次衬砌后该段洞室围岩喷锚衬砌安全性的问题。同时，依据相关规范和文献资料，对斜井Ⅲ级围岩喷锚衬砌段的沿程阻力系数进行修正，据此分析计算出隧道的风道压力损失，并与原设计的相关参数进行综合比较，确保在满足隧道通风系统设计要求的前提下节约工程造价。结果表明： 1）在地质围岩条件较好的地段，斜井取消二次衬砌满足规范要求，且具有足够的安全富余度； 2）在斜井喷锚衬砌的壁面粗糙度不超过30 mm、通风设备等参数增大10%的设计富余量，可抵消斜井段取消二次衬砌对该段压力损失的不利影响。

The secondary lining cancellation in the ventilation inclined shaft of highway tunnel has an impact on the stability and ventilation of the cavern. In order to solve this problem, the #1 inclined shaft of Qinling Tiantaishan tunnel is taken as an example to analyze the safety issue on the shotcrete lining of surrounding rock of this section of the cavern after the secondary lining cancellation according to the stratum characteristics and construction conditions of the grade Ⅲ surrounding rock section and considering the aspects such as specification requirements, structrual safety and durability.

 Meanwhile,  according to relevant specifications and literatures,  the frictional resistance coefficient along the route of the lining section of the surrounding rock shotcrete of grade Ⅲ inclined shaft is modified, and based on this analysis, the pressure loss of the tunnel air duct is calculated. A comprehensive comparison is made with the relevant parameters of the original design to reduce project cost under the premise of meeting the design requirements of the tunnel ventilation system. The results show that: (1) In the section with good geological surrounding rock condition, when it meets the specification, the cancellation of the secondary lining in the inclined shaft has sufficient safety margin. (2) In the inclined shaft, the wall surface roughness of the shotcrete lining does not exceed 30 mm, and the ventilation amount increase by 10% of the design air volume surplus of the equipment can offset the adverse effect of the cancellation of the secondary lining in the inclined shaft section on the pressure loss in this section.