Evolution law and application of permeability in gob without coal pillar and self‐formed roadway

Roof-cutting and pressure-releasing technology are used to cut out the pressure transmission line of critical blocks in roof, causing roof totally collapse gob, while NPR large deformation anchor cable support keeps highway its self-formed state. The gangue compactness has increased greatly when fully collapsed filled gob's edge. At end working face, void ratio between rock loose area is decreased, resulting an observable shortening airflow disturbance distance at face a change disaster gas accumulation law deep gob. It obtain permeability characteristics gob avoid hazardous migration. evolutionary model mined-out region created based on analysis movement overburden strata “Z” ventilation built research following key conclusions reached: 0–10 m exchange zone severe, 10–45 return weak, 45–190 section 190–280 confluence enhances top corner's weak air area. 0–50 part Roadway wide leakage channel, good sealing methods have significant impact face. two-dimensional constructed by comprehensive quantification main controlling factors, such as broken-expand, pressure, filling degree, can represent migration panel extent, reliability evolution confirmed through data comparison analysis.