Comparative study of dust pollution and air quality of tunnelling anchor integrated machine working face with different ventilation

Abstract

To study the influence of the air volume of the dust removal fan on dust diffusion during the excavation process, in this study we selected a fully mechanized excavation face with an anchor-integrated tunneling machine for simulation research. We sought to determine the optimal dust removal air volume. ANSYS FLUENT software was used to simulate the working environment of the dust removal fan under different air volumes. Through analysis of the dust movement law of air flow, the dust accumulation position and state are observed. As the exhaust air volume continues to increasing, the same trend is seen with the increase in the wind speed in the tunnel, and dust accumulation and diffusion are effectively controlled. An analysis of temporal and spatial evolution of dust migration showed, that when the exhaust volume Qs reaches more than 300 m3/min, the dust accelerates to the rear of the roadway, and the change in dust distribution is no longer obvious. Considering the situation in the field, it was shown that the optimal exhaust volume was Qs = 300 m3/min. We also found that with increasing air extraction volume, the air-flow speed in the roadway accelerated, which strengthened the pollutant discharge capacity of the far-pressing-near-absorption (FPNA) ventilation system. Finally, field tests were performed to analyze and compare the simulated data with actual data. The deviation rate was < 15%, thus the reliability of the numerical simulation was verified. The research methods and conclusions of this study provide an important reference for the effective control of construction tunnel dust and cleaner production, the protection of tunnel workers’ health, and the optimization of tunnel ventilation systems.