Research on influencing factors of rock breaking efficiency under ultrasonic vibration excitation

Abstract

The ultrasonic vibration rock-breaking technique shows broad application prospects in the hard-rock-breaking domain. The rock-breaking efficiency strongly depends on vibration parameters. This study performed rock-breaking tests of red sandstone samples under different static loads combined with ultrasonic vibration. The test results show that the penetration depth of the exciter into the rock and the rock-breaking range were exponentially related to the applied static load. Single-factor simulations and orthogonal tests were performed via the commercial particle flow code software to examine the effects of parameters such as vibration amplitude, frequency, loading surface size, confining pressure on rock damage, fracture characteristics, and rock-breaking efficiency. In contrast to the confining pressure, the increased vibration amplitude, frequency, and size of the loading surface promoted rock fracture and energy dissipation. The vibration frequency, amplitude, and the size of the load surface were determined as the key factors that affected the intrusion depth into rocks, the rock-breaking area, and the total number of cracks, respectively.