Forced-exhaust-air curtain dust removal measures of tunnel blasting dust based on CFD and orthogonal experiments

To minimize the dust removal duration associated with tunnel blasting excavation, this study employs on-site measurements and numerical simulations within a railway tunnel to investigate the dynamics of blasting dust during construction. On-site, a dust meter is utilized to monitor the blasting dust in real-time. Utilizing one-dimensional uniform turbulent diffusion theory and numerical simulation, we obtained the total mass of dust present on the surface during tunnel blasting excavation. Building upon the observed diffusion patterns of on-site dust, numerical simulations were conducted to evaluate the efficacy of dust removal in the tunnel using forced, exhaust, and air curtain ventilation methods. Forty-nine sets of orthogonal experiments were established, and, in conjunction with numerical simulation calculations, it was determined that the total amount of blasting dust in the tunnel amounted to 178.1 kg. The orthogonal experimental range analysis revealed that the hierarchy of factors influencing dust removal time was as follows: forced ventilator flow > air curtain flow > exhaust ventilator flow > exhaust ventilator length. From the orthogonal experimental results, the optimal parameters for the forced-exhaust-air curtain dust removal method were identified as follows: the exhaust ventilator length was 4 m, the forced ventilator flow was 26 m3/s, the exhaust ventilator flow was 40 m3/s, and the air curtain flow was 28 m3/s. Under these parameters, the majority of dust in the tunnel was reduced to a safe level within 900 s of initiating blasting ventilation. This investigation into dust removal techniques during tunnel blasting presents a methodology for rapid dust mitigation and serves as a reference for the implementation of on-site dust removal strategies.