Acoustic wave test on mechanical properties variation of rocks under different damage degrees

The damage degree can be characterized by the acoustic wave velocity of rock masses effectively. The rock samples are pre-damaged by the artificial cyclic loading, and the damage degree is determined by acoustic determining method. Then the mechanical properties of rock samples under different damage degrees are studied through triaxial compression test. The relationship between the decrease of acoustic wave velocity and the variation of the mechanical parameters of rock masses is established. The results show that, when the acoustic wave velocity of rock samples decreases by 5%-8%, the value of the cohesive of rock samples will reduce by 15%-25%, and the internal friction angle will increase by 14%-32%. It is shown that using the reduction of the acoustic wave velocity to describe the change of the rock mass parameters is feasible, because the rock is hardly damaged in the case of acoustic wave testing. So according to the field measurement data of the variation of the acoustic wave velocity, the change of rock mass parameters can be estimated to a certain extent, the bearing capacity of rock mass in damage zone can be further illustrated.