The Micro Vibration Equation of Rock and Its Analysis in Flat Indenter Basing on the Principle of Least Action

Impact frequency of drill tools, vibration displacement of rock and other factors play a key role on the impact efficiency of vibration and rock breaking effect in the percussion drilling. In this paper, the micro vibration equation of rock in the impact of indenter was established based on the principle of least action. Then the relationship among vibration displacement of rock and quality and natural frequency of rock, impact force and impact frequency of indenter and time were analyzed. The results show that the curve of vibration displacement is kind of shape of cosine function, its size fluctuates up and down in the equilibrium position with the changes in various factors; The greater the impact of flat indenter is, The smaller the quality of rock is, the greater the vibration displacement of rock is; The closer the impact frequency of indenter and natural frequency of rock are, the greater the vibration amplitude of rock is, and it is significantly higher than the situation which the difference of impact frequency of indenter and natural frequency of rock is large.