Table 1: The basic parameters of the model.

  Value   Item   Value
  The top depth of the coal mine/m   400   The scale of the model   85m*95m*48m
  Average thickness of the coal stratum/m   48   Initial pressure/ kPa   750
  Average porosity   0.04   Initial methane content   11.5m3/t
  Average Permeability of matrix/(10-3μm2)   0.05   Density of coal rock/(kg/m3)   1300
  Average Permeability of fracture/(10-3μm2)   0.5   Initial stress/kPa   810
  Biot's constants   1.0   fracture interval/m   40