Unloading Mechanics and Energy Characteristics of Sandstone under Different Intermediate Principal Stress Conditions

Table 3

The energy of unloading and failure points under different .

Initial stress (MPa)	Unloading point energy (MJ·m^−3)			Unloading failure point energy (MJ·m^−3)			Unloading energy increase (MJ·m^−3)
	U	U^e	U^d	U	U^e	U^d	△U	△U^e	△U^d
20, 5, 5	0.32	0.30	0.02	0.49	0.31	0.18	0.17	0.01	0.16
20, 11, 5	0.37	0.33	0.04	0.55	0.34	0.21	0.18	0.01	0.17
20, 17, 5	0.43	0.38	0.05	0.65	0.38	0.27	0.22	0.00	0.22
20, 20, 5	0.49	0.42	0.07	0.75	0.43	0.32	0.26	0.01	0.25