Discrete element simulation for investigating fragmentation mechanism of hard rock under ultrasonic vibration loading

Abstract

With the gradual depletion of shallow resources, the energy exploration depth has been increasing and condition becomes complex. 1 Consequently, the explorations face increasingly harder rocks with higher strengths. Breaking hard rock rapidly in petroleum and mineral exploration is a popular and significant topic. 2-6 However, the current technologies cannot meet the demands of quick drilling. It is necessary to develop a more efficient technology for hard rock exploration. To achieve this goal, the assisted ultrasonic vibration technique (ultra-high-frequency cyclic loading), combined with the traditional drilling method, was first introduced by researchers at Aberdeen University. 7 To implement this technology more effectively, studies were conducted on rock-breaking characteristics under ultrasonic vibrations and optimization of the vibration parameters. The studies conducted by Wiercigroch et al 8 showed that the high-frequency axial vibration significantly enhanced the breaking rates compared to the traditional method. Subsequently, uniaxial compressive strength experiments were conducted on fine granite by Yin et al 9 to demonstrate that there exists a static force threshold for this technology. They found that the optimal value range of static loading was 200-300 N. An

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