Abstract: In order to study the effect of pressure released and permeability improved induced by working face arrangement under long distance coal seam upward mining, according to the geological conditions of the 11223 working face in Panji No.2 Coal Mine, the FLAC^3D numerical simulation software was used to study the distribution character of stress field, displacement field and crack field after the pressure relived mining, and make sure the pressure released and permeability improved area depend on stress relief coefficient under different mining condition. The results indicate that: the working faces were vertically arrangement in the west second segment, the mining of lower 11223 working face can induce remarkable change in stress field, displacement field of upper 11224 working face, the stress relief coefficient is 90.37% in the middle part of 11224 working face, which can make a good stress relief effect. However, in the east first segment, the 11224 working face used the 90 m outward stagger mode in ventilation entry and 90 m inner stagger mode in conveyor entry, the stress relief coefficient is 88.97% in the lower part of 11224 working face, this can make a good stress relief effect, while the stress relief is very feeble in the upper part. To sum up, it can make a better effect of pressure released and permeability improved when working faces apply vertically arrangement under long distance coal seam upward mining.

Key words: simultaneous exploitation of coal and gas, stress relief coefficient, protective seam mining, pressure released and permeability improved effect, long distance coal seam