为解决高海拔隧道爆破作业、低气压导致CO体积分数迅速升高问题，通过设计CO监测传感器布置方案，提升传感器监测的准确性，缩短爆破后作业暂停时间，降低施工人员CO暴露风险。以海拔3 500 m的压入式通风施工隧道为研究对象，基于现场传感器监测数据和三维非稳态通风数值模拟方法，分析随着隧道挖掘的推进风管出口至掌子面距离对隧道内流场特征及CO输运规律的影响。结合监测断面CO体积分数分布与通风距离之间的变化关系，提出传感器优化布置方案。结果表明： 1）现有施工过程，所布置的传感器监测时间与呼吸区高度范围内CO实际排出时间存在偏差，且该偏差随着风管出口与掌子面距离的增大而逐渐减小。2）对于所研究的隧道，若采用固定式传感器，需在隧道两侧壁面距地面3.6 m处对称布置双传感器。3）若采用可移动式传感器，则应依据风管末端与掌子面的距离动态调整，当距离小于30 m时，优先布置于隧道左侧壁面3.6 m高度处； 当距离不小于30 m时，则布置于右侧壁面相同高度。
In high-altitude tunnel blasting operations, reduced atmospheric pressure leads to a rapid increase in carbon monoxide (CO) volume fraction. Designing an optimized layout scheme for CO monitoring sensors is beneficial to improving sensor detection accuracy, shortening suspension period of operations after blasting, mitigating CO exposure risk for construction personnel. A case study is conducted on a pressurized ventilation construction tunnel at an altitude of 3 500 m, and on-site sensor monitoring data and a three-dimensional unsteady ventilation numerical simulation method are employed to analyze the influence of the distance between the ventilation duct outlet and the tunnel face on the flow field characteristics and CO transport patterns. Based on the relationship between the distribution of CO concentration at monitoring sections and the ventilation distance, an optimized sensor placement strategy is proposed. Findings are as follows: (1) In existing construction processes, there is a discrepancy between the monitoring time recorded by deployed sensors and the actual clearance time of CO within the breathing zone height range. This deviation gradually decreases as the distance between the duct outlet and the tunnel face increases. (2) For the tunnel under study, dual sensors should be symmetrically installed on both sidewalls at a height of 3.6 m above the ground when using fixed sensors. (3) The locations of sensors should be dynamically adjusted according to the distance between the end of the ventilation duct and the tunnel face when using movable sensors. When the distance between the end of the ventilation duct and the tunnel face is less than 30 m, priority should be given to installing the sensor on the left sidewall at a height of 3.6 m; whereas the distance is not less than 30 m, it should be installed on the right sidewall at the same height.
