考虑风筒破损对隧道施工过程中CO排出的影响机制

为研究隧道施工通风过程中风筒破损对一氧化碳（CO）排出的影响，依托城开高速鸡鸣隧道，运用孔口流量理论，考虑风筒内流速、孔口与开挖工作面距离和孔口数量三个因素，基于数值模拟方法，研究风筒破损对CO排出的影响。研究表明：在风筒破损面积相同的前提下，漏风率随送风量的增加而增大；开挖工作面处的CO浓度在通风1min后达到峰值，约为3.5%；风筒破损会对隧道内的CO稀释产生滞后效应，滞后时间为1~3min并且送风量越小滞后效应越明显，最终导致距洞口25m范围内的CO浓度高于规范要求；通风长度区域内，三个因素中对CO排出的影响依次为：风筒内流速>孔口与开挖工作面距离>孔口数量；整体隧道内，影响依次为：风筒内流速>孔口与开挖工作面距离>孔口数量。并提出了通风设计和孔洞修补两方面的建议。

Influence of damaged duct on carbon monoxide emission process during construction in tunnel

To investigate the influence of damaged duct on carbon monoxide''s emission during tunnel construction, relying on the Ji-ming Tunnel of Cheng-kai Expressway. The orifice flow theory was used to analyze, and the velocity in duct, the distance between holes and working face and the number of holes were considered as factors. The orthogonal test was carried out to research the influence of duct damage on the distribution of CO. The results show: the air leakage rate would be increased by the increase of the air of the working face. When the ventilation time is 1min, the CO concentration would research its peak at the working face, which is about 3.5%. A lag effect on the dilution of CO in the tunnel would be caused by the damage of duct. And the lag time would be 1 to 3 minutes, and it would be more obvious with the decreasing of air demand at working face. The result that the concentration of CO within 20m from the entrance of the tunnel being higher than the requirements finally was also caused by the damage of duct. In ventilation region, the influence degree of the three factors on the dilution and discharge of CO is: the velocity in the duct > the distance between the holes and working face > the number of holes; In the whole tunnel, the order turns into: the velocity in the duct > the distance between the holes and working face> the number of holes. There are suggestions on ventilation design and holes repair.