Mechanical Properties of Bump-Prone Coal with Different Porosities and Its Acoustic Emission-Charge Induction Characteristics under Uniaxial Compression

Figure 11

Damage variable evolution with stress and axial and volumetric strain of coal with different initial porosities under uniaxial compression. (a) Specimen 21^# with in group III; (b) specimen 9^# with in group II; (c) specimen 4^# with in group I. In the figures, stress is denoted by the black curve, volumetric strain by the olive curve, and damage variable by the blue curve.

(a)

(b)

(c)