Study On Dust Migration Regularity And Control Technology In Drilling And Blasting Method Of Highway Tunnel Construction

Drilling and blasting method of highway tunnel construction is the most serious damaging area of dust. The original dust concentration during operation of each procedure exceeded the national health standard number, which was a serious threat to workers’health and safety. So based on the high concentration dust on highway tunnel drilling and blasting construction, the Xinzhuang tunnel of Jingkun Highway was studied by theoretical analysis, field data measurement, numerical simulation, experimental and field application.Dust generation mechanism on drilling and blasting was studied. According to the forces act to dust in the air, the dust motion equation and its solution mathematical model was derived based on three physical conservation laws.Reference to GBZ/T192.1-2007and the relevant standards, dust measurement scheme was designed and implemented. The dust concentration and airflow distribution was obtained by measurement. The parallel model device for the specific situation in the tunnels and the number of similar criteria derived were designed according to the resemble theory and the Dual-Phrase equation motion. Through the model, the airflow movement and dust concentration distribution in the working face was studied. At the same time, the geometical model and mesh partition was built based on field and similar simulation data, and Numerical simulation of the airflow and dust migration regularity in the tunnel was made with CFD software FLUENT6.2. The result matches well with the related survey data. Based on actual conditions, the control measure of gas-water spray system and water stemming dustfall agent reducing dust was put forward.Based on the analysis of gas-water spray mechanism, and combining with the characteristics of tunnel dust, a new gas-water spray nozzle was selected and tested; the reasonable technological parameters of gas-water spray system and implementation plan was determined. By measuring the surface tension of the solution, powder forward osmosis method and determination of toxicity reduction of nitrogen oxides, the basic material of water stemming dustfall agent was determined:namely:the optimal base material concentration is0.3%, the optimal surface-active agent is0.5%, two additives with the mass concentration of0.1%and0.03%. Based on the actual situation, the specific production and fill scheme was determined.Through out apply two kinds of dust suppression measures in the field, the field test results show that the operating environment has been significantly improved, and the dust concentration is greatly reduced; the each process average removal efficiency on all size dust reached48%-80%, and the each process average removal efficiency on respirable dust reached69%-74%. Compared with the traditional ventilation removal dust has been greatly improved.