Study on gas diffusion evolution and emergency evacuation in tunnel with sudden wind shutdown

In order to solve the problem that a large amount of gas emitted from the newly excavated coal wall in the driving roadway after the sudden wind shutdown causes the gas volume fraction to rise rapidly and thus endangers the safety of the operators, this paper proposes a mathematical model for the space-time evolution of the gas volume fraction in the driving roadway during the wind shutdown, and uses the multi-physical field coupling software to simulate and study the space-time evolution law of the gas emission, gas volume fraction, and oxygen volume fraction in the driving roadway after the sudden wind shutdown accident. The results show that the gas diffusion in the roadway after the ventilation is low Reynolds number laminar flow; the comparison and analysis trend of theoretical calculation data is consistent with the measured data of 2207 heading roadway in Taiyue Coal Mine; the escape speed of the personnel involved in the danger must be greater than 3.91 m/min, the best evacuation time is 7-25 min, and the minimum time is 30 min before the oxygen volume fraction in the roadway falls to the low oxygen level. The research results provide a theoretical basis for formulating the emergency response plan for coal mine gas safety accidents and scientifically arranging the emergency evacuation of operators.