The effects of Air-vents’ Layouts on Behaviour and Pollution of Dust in Tunnle Construction Environment

Abstract

Abstract Study on powder behavior is the key to dust pollution prevention and control in tunnel construction environment, using wind energy to control dust diffusion is a common and effective dust control method at present. In this paper, the numerical simulation and field measurement were used to study the powder diffusion in construction of a tunnel boring machine (TBM)-based tunnel, in which the movement and diffusion properties of the powder in the tunnel were achieved and analyzed. By adjusting the height of the exhaust vent and the secondary blowing distance (LP), the quality of air in the tunnel was optimized. The accuracy of the simulation results was also verified by the field measurements. The results showed that when the height of the dusty return airflow (HW) is close to that of the exhaust vent (HE), the rock-dust concentration in the tunnel could be reduced to a certain extent. When LP < 50 m, the primary and secondary blowing airflows could form a coupled wind field in the middle of the tunnel to limit the further backward diffusion of the rock-dust. When LP > 50 m, the dust-control air-curtain could be formed within 18.83 m away from the heading. When LP = 60 m, the rock-dust in the tunnel was effectively controlled, and the diffusion distance of the rock-dust was less than 16.4m as well.