高瓦斯特长高铁隧道通风方案设计及监测分析

成都至自贡高铁白云山隧道全长13 340 m,为特长高瓦斯隧道，多工区、多阶段施工通风问题严重制约着隧道运营施工与人员安全。通过工作面最大通风量、最大供风量及沿程风压损失对不同工区施工阶段进行通风计算，设计单工区通风方案及隧道总体贯通顺序，并采用水气分离方法处理地下水及自动安全监控系统实时监测隧道瓦斯浓度。分析表明：施工的大部分时间内，2#～6#斜井的瓦斯浓度均偏低，说明合理的通风方案及工区贯通顺序可以有效降低隧道瓦斯浓度；采用水气分离方法对地下水进行处理，将地下水和瓦斯分别排出，可进一步降低隧道内瓦斯浓度；监控系统对2#、3#和6#斜井出现的瓦斯排放异常情况及时报警提示并断电保护，保证了隧道施工进度及人员安全。针对特长高瓦斯隧道多工区、多阶段施工通风，基于隧道通风方案、贯通顺序、水气分离处理及瓦斯监测等方面建立一套完整的通风监测设计方法，为类似工程提供指导。

Design and monitoring analysis of ventilation scheme of high gas long high-speed railway tunnel

The Baiyunshan tunnel of Chengdu-Zigong high-speed railway has a total length of 13340 m. The ventilation problem of multi-work area and multi-stage construction of long high gas tunnel seriously restricts the tunnel operation and construction and personnel safety. The ventilation of different working areas was calculated through the maximum air volume, maximum air supply volume and air pressure loss along the way. The ventilation scheme of single working area and the overall tunneling sequence were designed. The water and air separation method was used to treat groundwater and the automatic safety monitoring system was used to monitor the gas concentration in the tunnel in real time. The analysis shows that: during most of the construction time, the gas concentration of the 2#~6# inclined shaft is low, which indicates that the reasonable ventilation scheme and the penetrating sequence of the working area can effectively reduce the gas concentration of the tunnel; The water gas separation method is used to treat the groundwater and discharge the groundwater and gas respectively, which can further reduce the gas concentration in the tunnel; The monitoring system timely alarms the abnormal gas emission of 2#, 3# and 6# inclined wells and power off protection, which ensures the progress of tunnel construction and personnel safety. In this paper, a set of complete ventilation monitoring design method is established based on tunnel ventilation scheme, through sequence, water and gas separation treatment and gas monitoring for multi-area and multi-stage construction ventilation of long high gas tunnel to provide guidance for similar projects.