The affecting factors of permeability evolvement of coal seam

The influence of stress, Klinkenberg effects and shrinkage effects to coal seam permeability are analyzed. The research results show that as gas in coal seam desorbs and gas stress decreases, coal matrix shrinks so as to make adsorption swelling deformation smaller and increase the permeability of coal seam. When stress increases and gas pressure is not changed coal seam permeability decreases. Because of the existence of Klinkenberg effects gas flow speed and coal seam permeability increase. The researches have important significance to prevent gas disaster and develop gas resource in mine.