Analysis of Impact Hammer Rebound to Estimate Rock Drillability

Summary¶In this paper, the piston rebound common to both the Schmidt Impact Hammer and down-hole hammer drills has been analyzed and calculated by means of stress wave theory and the energy conservation law. A quantitative relationship between the amount of rebound of the piston and the impact resistance index, or hardness of the rock, has been established. Those analytical results will not only be of benefit in acquiring a deep understanding of the usable range and condition of the Schmidt Impact Hammer, but also provide a definite answer to the feasibility of using the hammer rebound in drills with down-hole hammer tool to carry out a real time measurement of the nature of the formation under the bit.