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

<div>True triaxial unloading test of stress difference-AE curve. (a) Intermediate principal stress is 3 MPa. (b) Intermediate principal stress is 6 MPa. (c) Intermediate principal stress is 9 MPa.</div>

Advances in Civil Engineering

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Figure 6

Figure 6: Research on Coal Mechanical Properties Based on True Triaxial Loading and Unloading Experiment 