English：

In recent years, with the increasing number of long and large tunnel projects, problems suchas difficulty in dust removal during construction and insufficiency in environmental protection, etc. , needurgent solutions. To achieve efficient and safe excavation, based on the Shengli Tunnel in the TianshanMountains, combined with numerical simulation on the basis of literature research at home and abroad,the airflow structure and dust migration characteristics of the long tunnel after blasting werecomprehensively analyzed, and the design parameters of tunnel forced ventilation were optimized. Themeasured tunnel dust concentration and wind speed verify the accuracy of the simulation. After blasting,the wind speed at 20m in front of the tunneling face reaches a maximum of about 1. 47m / s, and the windspeed at the stable section is about 0. 11m / s. When the construction ventilation is 900s, the peak valueof dust concentration is reduced to 25. 65mg / m3. The dust concentration within 200m from the excavationface meets the construction requirements. The farther the air duct is from the excavation face, the moreregular the airflow near the tunnel is, but the wind speed in the tunnel is gradually reduced. When theair duct is 20m away from the excavation face, the construction ventilation effect is the best. Thediversion fan can accelerate the diffusion rate of dust particles in the tunnel to the entrance direction andsignificantly reduce the dust concentration in the tunnel. When the diversion fan is located in the middlesection of the tunnel, the dust particles can be discharged to the outside of the tunnel faster.