Numerical study on fine dust pollution characteristics under various ventilation time in metro tunnel after blasting: Fid-Bau Portal

Numerical study on fine dust pollution characteristics under various ventilation time in metro tunnel after blasting

Xie, Zhuwei / Xiao, Yimin / Jiang, Congxin / Ren, Zhili / Li, Xueqin / Yu, Kecheng

Abstract In recent years, many metro tunnels have been constructed; the dust pollution caused by tunnel construction has attracted the attention of scholars at home and abroad. In these projects, the entire working zone is rapidly covered by fine dust after blasting, causing serious pneumoconiosis to the workers. To efficiently remove the fine dust within the working zone ahead of the driving face, a combination of the numerical simulation, field measurement, and the blasting ventilation model were used to analyze the characteristics of dust diffusion in the personnel breathing zone under blowing ventilation. Moreover, the effect of the volume flow rate of forced air duct and total explosive mass on ventilation time under different upper limits of dust concentration in the working zone was investigated in depth. The simulation results showed that the airflow field in the 1.6 m and 3 m personnel breathing zones consisted of four regions: the backflow region, vortex region, multi-direction region, and stable region with a same direction. However, the working zone ahead of the driving face suffered from more serious dust pollution in the 3 m personnel breathing zone. The relationships between ventilation time and the three variables of upper limit of dust concentration, volume flow rate of the forced air duct, and total explosive mass satisfied logarithmic, power, and logarithmic functions, respectively. Furthermore, the computational formulas for ventilation time under different construction scenarios are presented as multivariate nonlinear functions. The accuracy of the simulation results was validated by theoretical results from the blasting ventilation model and field-measured results.

Graphical abstract Display Omitted

Highlights • CFD method, combined with field measurement and blasting ventilation model, was used to analyze the dust diffusion pattern. • The working zone ahead of the driving face suffered from more serious dust pollution in the 3 m personnel breathing zone. • The effects of the volume flow rate of the forced air duct and total explosive mass on ventilation time were determined. • The formulas of ventilation time under different construction scenarios are presented as multivariate nonlinear functions.