An Experimental and Numerical Study on the Mechanism of High-Voltage Electro Pulse Rock-Breaking

As a novel rock-breaking technology, the high-voltage electro pulse rock-breaking boring (EPB) technology has a broad prospect for high efficiency and low energy consumption rock-breaking boring. But the mechanism of rock-breaking under the action of high voltage electro pulse is not clear. In this study, First, red sandstone is selected as the boring sample, the high-voltage electro pulse breaking experiment on red sandstone is carried out with an electrode bit with a diameter of 80 mm and the electrode spacing of 35 mm, the red sandstone is broken down by the shock wave from the electric blasting in plasma channels of the red sandstone, and the complete drilling in the red sandstone is realized. Second, the electric current is collected during the experiment, in addition, the parameter of the shock wave is obtained based on the discharge circuit model and the shock wave model developed in the previous study. The parameters of shock wave and discharge energy are obtained based on the electric discharge circuit model and the shock wave model established in the previous study. Finally, the breakdown process of red sandstone by the shock wave is simulated, and the high-voltage EPB mechanism is analyzed, the simulation result is consistent with the experiment result. Experimental and simulation results indicate that the breakdown process of red sandstone under the action of high-voltage electro pulse includes the electric blasting occurrence stage and the energy dissipating stage, the red sandstone is broken down by the resultant mechanisms of shear failure and tension failure, but the shear failure is dominant.