Progressive Failure and Acoustic Emission Characteristics of Red Sandstone with Different Geometry Parallel Cracks under Uniaxial Compression Loading

Table 3

The stress and energy index of different crack modes.

Crack mode	Group 1	Group 2	Group 3	Parameters
Wing crack	8.55	9.64	6.85	Stress (MPa)
	1670	6940	108	Energy index
Rock bridge coalescence	20.70	9.64	—	Stress (MPa)
	6050	6940	—	Energy index
Specimen failure	28.12	11.79	20.24	Stress (MPa)
	9380	15353	11927	Energy index