Study on the rock-breaking process based on a high-voltage electropulse boring damage model

Abstract

High-voltage electropulse boring (EPB) is a new drilling method with great potential for drilling and industrialization. The existing high-voltage electropulse boring damage model based on PFC2D does not calibrate the parameters of the rock used in the rock-breaking test, so it is impossible to ensure that the simulated model is consistent with the mechanical properties of the rock in the actual rock-breaking test. The parameters of natural rock were calibrated based on the data results of indoor uniaxial compression and Brazilian splitting tests. Based on the calibrated micro parameters, a geometric model consistent with the size of the high-voltage EPB test was established, and the EPB process was simulated. The simulation results indicated that the shear failure mainly occurred in the process of high-voltage EPB, accompanied by a certain amount of tensile failure. Then, the EPB test was carried out with the high-voltage EPB test system, and an irregular broken hole with a diameter of 60 mm and a depth of 22.5 mm was obtained. The breaking effect was visualized by point cloud software. The results of the EPB rock-breaking test verified the effectiveness of the calibrated parameters. Finally, the influence of the fractures on the rock-breaking effect of high-voltage EPB was studied through the geometric model established with the calibrated parameters. The results showed that the existence of fractures would reduce the energy consumption in the rock-breaking process, and the crushing area tended to develop in the direction of fractures.

Keywords

• high-voltage
• electropulse boring
• rock-breaking process
• pfc numerical simulation
• rock-breaking test