Ultrasonic transmission analysis of internal structure evolution in fractured rocks

The mechanical properties of P-wave propagation in rock fractures, obtained by ultrasonic testing, were used to deduce the relationship between the energy change and the internal rock structure evolution. Then, uniaxial compression testing with ultrasonic monitoring was performed using limestone rock mass specimens with different natural initial fracture types. The internal crack growth rate was obtained from the whole loading time and the ultrasonic waveform parameters. For specimens with different initial structures, the crack growth rate showed different features significantly with the change in axial stress. The crack growth rate in fractured rocks, calculated from the elastic mechanics model for transmitted waves, can represent changes in crack growth during loading. This rate may be used as initial input for artificial intelligence to evaluate rock mass stability at different loading stages in the field of engineering.