EXPERIMENTAL INVESTIGATION INTO THE REGIMES OF PERCUSSIVE DRILLING OF ROCKS
The article shows the results of experimental investigation into the regimes, wherein the percussive drilling of crystalline rocks is performed. Its samples are being destroyed in laboratory conditions with drilling indenters. The volume of rock, destroyed by the impact of two indenters at horizontal section of a sample and by the impact of one indenter near the edge of deep hole is measured. At that the regimes of an impact are changed - its mechanical energy and horizontal location of indenters. According to experiments results, simulation of break-ups dependence on the mentioned regimes is performed with the method of nonlinear functional and factorial regression. It is shown that the models acquired, show the regularities of a break-up with a decent accuracy and reliability. The article provides their theoretic interpretation based on elastic-brittle features of rock and the notion of quasi-resonant breaking-up of its walls which are formed between the indenters. Optimal regimes of percussive drilling providing maximum level of destruction and its minimum power intensity are determined from the models. Practical conclusions and recommendations are given.