Research on the Nonlinear Characteristics of Acoustic Emission and Damage Mechanism of Gassy Coal under Unloading Conditions

Table 1

Experimental condition.

Experimental name	Number	Confining pressure (MPa)	Gas pressure (MPa)	unloading rate (MPa/s)	unloading rate (MPa/s)
Conventional triaxial-0	1, 2, 3	19	0	—	—
Conventional triaxial-0.2	4, 5, 6	19	0.2	—	—
Conventional triaxial-0.5	7, 8, 9	19	0.5	—	—
Conventional triaxial-0.8	10, 11, 12	19	0.8	—	—
True triaxial loading and unloading experiment-0	1, 2, 3	19	0	0.005	0.02
True triaxial loading and unloading experiment-0.2	4, 5, 6	19	0.2	0.005	0.02
True triaxial loading and unloading experiment-0.5	7, 8, 9	19	0.5	0.005	0.02
True triaxial loading and unloading experiment-0.8	10, 11, 12	19	0.8	0.005	0.02