Experimental Investigation of Rock Damage Induced by Ultrasonic High-Frequency Vibration Under High Confining Pressure

Ultrasonic vibration can effectively improve the efficiency of rock breaking. In the actual process of drilling and breaking rocks, rocks will be affected by symmetrical ground stress in the formation. Therefore, in this paper, symmetrical confining pressure is applied to four surfaces of rocks by self-developed experimental equipment to simulate the symmetrical ground stress of the formation, and 64 groups of mixed tests are carried out with confining pressure, static load and vibration time as variables. The damage degree is evaluated by comparing the compressive strength of rock before and after vibration. The experimental results show that ultrasonic vibration can reduce the compressive strength of rock, increase the static load and vibration time during vibration, and increase the damage degree of rock. When the symmetric confining pressure increases, the formation and expansion of rock cracks can be inhibited, and the damage effect of ultrasonic high-frequency vibration on rock can be reduced. At the same time, a theoretical model is established to explain these phenomena.