Study on dust distribution in a highway tunnel during the full-face excavation with Drilling-Blasting method

Dust problem is serious in a highway tunnel during the full-face excavation, particularly after blasting of tunnel face. In order to solve the problem of dust pollution after blasting effectively, this study investigated the space-time evolution law of dust and inhalable particles within 100 s after blasting under blowing ventilation. First, the Euler-Lagrange method is used to simulate the coupled motion of air and dust. Then, the influences of air velocity on the distribution of dust and inhalable particles are considered, and the simulation results are verified by field measured data. The present study indicated that the heavier particles in the dust produced by blasting of tunnel face are deposited at the bottom of wind-return side in front of duct. The inhalable particles which particle size less than or equal to 10 & mu;m are more uniformly dispersed in the whole tunnel space, and the higher the air velocity, the shorter the time required for the process. In addition, by analyzing and fitting the particle moving distance along the length of tunnel, the approximate time required for dust to migrate to a certain location can be predicted. The prediction of space-time evolution law of dust and inhalable particles in this study can provide some guidance for practical engineering cleaner production.