为明确施工隧道变风量通风条件下高海拔等关键因素对CO运移的影响机制，准确掌握掌子面爆破后CO的体积分数分布规律，以海拔3 500 m地区采用压入式通风的施工隧道为研究对象，基于现场实测数据，构建三维非稳态通风数值模型，并运用专业数值模拟软件对不同工况条件下CO动态运移及时空演化特征进行分析； 同时，引入灰色关联法，定量解析CO体积分数降低至暴露限值所需要的时间与各影响因素间的关联程度。研究结果表明： 1）在爆破后的通风过程中，隧道内截面CO体积分数峰值迁移的距离与通风时间满足二次函数关系。2）通过对比不同工况下隧道内CO时空分布特征可知，海拔越低、炸药用量越少、风管末端与掌子面距离越近、风管悬挂高度越高，CO体积分数降低至暴露限值所需的通风时间越短。3）在各影响因素中，炸药用量与风管末端与掌子面的距离对CO体积分数降至暴露限值所需时间的影响最为显著，灰色关联度分别达0.77和0.76； 海拔次之，灰色关联度为0.68； 风管悬挂高度的影响相对较小，灰色关联度为0.49。
It is of great significance to clarify the influence mechanism of key factors such as high altitude on CO migration under variable air volume ventilation in construction tunnels and accurately determine the concentration distribution of CO after tunnel face blasting. In this study, a case study is conducted on a construction tunnel with press-in ventilation at an altitude of 3 500 m, and a three-dimensional unsteady ventilation numerical model based on field measurement data is constructed. Professional numerical simulation software is utilized to analyze the dynamic migration and spatiotemporal evolution characteristics of CO under different working conditions. Further, the grey relation analysis method is employed to quantitatively analyze the correlation degree between the time required for CO concentration to decrease to the exposure limit and each influencing factor. The results show the following: (1) During the ventilation process after blasting, the migration distance of the CO peak value section in the tunnel satisfies a quadratic function relationship with ventilation time. (2) By comparing the spatiotemporal distribution characteristics of CO in the tunnel under different working conditions, it is found that the lower the altitude, the smaller the amount of explosives used, the closer the end of the air duct to the tunnel face, and the higher the hanging position of the air duct, the shorter the 〖JP2〗ventilation time required for the CO concentration to decrease to the exposure limit. (3) The grey relation analysis results show that among the influencing factors, the amount of explosives and the distance from the end of the air duct to the tunnel face exhibit the most remarkable influence on the time required for CO concentration to drop to the exposure limit, with grey relation degree coefficients of 0.77 and 0.76, respectively; the altitude comes next with a correlation coefficient of 0.68; and the influence of the air duct hanging position is relatively limited, with a correlation coefficient of 0.49.
