A numerical investigation into key factors controlling hard rock excavation via electropulse stimula

• 作 者: Daniel Vogler Stuart D.C. Walsh Martin O. Saar
• 机 构: Geothermal Energy and Geofluids, Institute of Geophysics, ETH Zurich, Zurich, Switzerland“,”Departme
• 出 处: 岩石力学与岩土工程学报（英文版）
• 发表日期: 2020年4期
• 关键词: Electropulse stimulation High voltage breakdown Numerical modeling Drilling Ther

Electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock surface. As such, it has the potential to confer significant advantages to mining and drilling operations for mineral and energy resources. Nevertheless, before these benefits can be realized, a better understanding of these processes is required to improve their deployment in the field. In this paper, we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating conditions. To that end, we investigate the maximum applied voltage within ranges of 120-600 kV, to observe the onset of rock fragmentation. We further study the effect of grain size on rock breakage, by comparing fine (granodiorite) and coarse grained (granite) rocks. Lastly, the pore fluid salinity is investigated, since the electric conductivity of the pore fluid is shown to be a goving factor for the electrical conductivity of the modeled system. This study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.