Study on tunnel ventilation and pollutant diffusion mechanism during construction period.

Area of Science:

• Engineering
• Environmental Science
• Fluid Dynamics

Background:

• Tunnel construction generates pollutants, necessitating effective ventilation for safety and environmental control.
• Understanding fluid dynamics is key to managing pollutant dispersal in confined tunnel environments.

Purpose of the Study:

• To investigate flow field characteristics and pollutant transport mechanisms in tunnels during drilling and blasting.
• To identify factors contributing to pollutant retention zones and develop optimized ventilation strategies.

Main Methods:

• Theoretical derivation and numerical simulation to analyze fluid flow and pollutant behavior.
• Mathematical statistics and an improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) for parameter optimization.

Main Results:

• Fluid instability and turbulence create vortex zones near the working face, leading to pollutant retention.
• Pollutant stagnant zones are caused by bypass effects, low-velocity regions, and fluid vortices.
• Pollutant dilution is enhanced by shorter air duct distances, while extraction increases with fan airflow.

Conclusions:

• Optimized ventilation parameters, considering air duct distance and fan airflow, are essential for effective pollutant control.
• An empirical formula for air supply volume calculation aids in selecting appropriate ventilation fans, ensuring efficiency and cost savings.