Numerical simulation study on the mechanism of coal spontaneous combustion plugging and air control in goaf of gob-side entry retaining

According to the characteristics of large air leakage intensity and complicated airflow migration regularity in goaf of the open gob-side entry retaining, the influencing factors of airflow migration in goaf of gob-side entry retaining were established, and the permeability distribution model of Y-type ventilation goaf was established. The method of parallelogram determination was proposed for dividing the lateral oxidation zone of the Y-type ventilation in goaf. On the basis of air leakage source plugging and wind control, numerical simulation method was used to study the plugging positions on the airflow migration law. The results show that the wind speed of air leakage near the side of gob-side entry retaining is higher than that on the other sides. Affected by the inertia of the wind flow, the air leakage speed at the lower corners of the working face along the deep direction of the goaf is relatively large, forming a airflow inertia impact zone; the width of the horizontal oxidation zone is reduced by leak-stopping measures, the angle between the horizontal oxidation zone and the working surface is increased, and the width of the longitudinal oxidation zone is not affected; when the lower corner is blocked, the area of oxidation zone in goaf is the smallest. The research results can provide a theoretical basis for coal spontaneous combustion air control technology in goaf of the gob-side entry retaining.