Failure Mechanism and Control of Lower Retracement Channel in Close-Distance Double-Thick Coal Seams

Table 2

Strain-softening parameters.

Properties	εp	εr	Cr (MPa)	Φr (°)
Value	0.007	0.013	0.23	11.4

Note: C_r is residual cohesion and Φ_r is the residual friction angle.