Numerical Simulation of Coupled Thermal-Hydrological-Mechanical-Chemical Processes in the Spontaneous Combustion of Underground Coal Seams

Figure 5

The distributions of permeability ratio at , 5, 10, and 20 days.

(a) 1 day, (-)

(b) 5 days, (-)

(c) 10 days, (-)

(d) 20 days, (-)