Characteristics of Bituminous Coal Permeability Response to the Pore Pressure and Effective Shear Stress in the Huaibei Coalfield in China

Table 4

Fitting formula.

Average effective normal stress (MPa)	Fitting formula
3.17		0.99
3		0.99
2.83		0.99
2.67		0.99
2.5		0.99