Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment

Figure 3

Failure section of coal in true triaxial unloading test. (a) Intermediate principal stress is 3 MPa. (b) Intermediate principal stress is 6 MPa. (c) Intermediate principal stress is 9 MPa. (d) Intermediate principal stress is 12 MPa.

(a)

(b)

(c)

(d)