Dust Migration Law in Working Area of Large Cross-section Tunnel by Mining Method

At present, there is no pertinence in the law of dust migration in the tunnel construction by mining method, although there are abundant researches. This paper studies the Qintai Tiantaishan tunnel through field measurement and numerical simulation, and analyzes the dust migration law under the conditions of drilling, mucking and guniting for the working area. The results show that: (1) Under all working conditions, the dust concentration tends to decrease in the area along tunnel face. And the higher the dust concentration, the more significant the decreasing trend. (2) When the dust concentration is small, there will be fluctuation trend. What’s more, the smaller the dust concentration, the earlier the trend appears. (3) The dust concentration under all working conditions exceeds the specification limit. Among them, the dust concentration is the highest under the condition of mucking, the next under the condition of drilling, and the lowest under the condition of guniting.