Deformation failure and damage evolution law of weathered granite under triaxial compression

To study the deformation failure and damage evolution law of weathered granite (WG) under different confining pressures, triaxial compression simultaneous acoustic emission (AE) tests were conducted on WG, and the mechanical and AE parameter characteristics of WG were obtained. It is shown that with the increase of confining pressure, the strength and modulus of elasticity of WG increase, and the failure pattern evolves from splitting failure to shear failure. Using the Mohr-Coulomb criterion, the cohesion c of WG is calculated to be 7.03 MPa, and the angle of internal friction phi is 61.95 degrees. Analysing the AE peak frequency and energy at the characteristic points of the differential stress-axial strain curves, it is evident that the confining pressure limits crack evolution. The fractal characteristics of the WG AE ringing counts at each confining pressure are good, and the correlations between their ln r-ln C(r) curves and the fitted curves are all above 0.90. The WG at each confining pressure showed an increasing growth rate in the values of the damage variables and a rapid and substantial decrease in the fractal dimension before failure occurred. The study's results can provide a theoretical basis for the stability analysis of the WG surrounding rock.

Automated summary

Triaxial compression simultaneous acoustic emission (AE) tests were conducted to study the mechanical and acoustic emission characteristics of weathered granite (WG) under different confining pressures. The results showed that the strength and modulus of elasticity of WG increased with increasing confining pressure, and the failure pattern evolved from splitting failure to shear failure. The analysis of AE peak frequency and energy revealed that confining pressure limited crack evolution. The study also found that the fractal characteristics of AE ringing counts at each confining pressure were good, and the damage variables showed an increasing growth rate before failure occurred.