Monitoring Study on Dust Diffusion in High Altitude Tunnel under Drilling and Muck Removal Conditions

In the high altitude area, the air density and the air pressure are low. In this paper, combined with a high altitude tunnel engineering in Tibet, the dust concentration during the drilling and muck removal was monitored, and tunnel dust diffusion situation was analyzed. The result shows that the dust concentration on the middle line of tunnel is higher than the dust concentration at the tunnel side. The dust concentration near the tunnel face is the highest. In the longitudinal direction, the change rule of the total dust and respirable dust concentration, are totally the same. With the increase of distance from tunnel face, dust concentration declines rapidly, then gradually become stable. The dust diffusion rule in the process of muck removal is basically similar to that of drilling process, but the dust concentration is larger, and the concentration of respirable dust accounts for a higher proportion than that in the drilling operation.