Study of rock fracturing generated by pulsed discharging under confining pressure

Some experimental results were obtained on rock fracturing without the confining pressure by using pulsed power technology. To study the effects of the stratum pressure on rock fracturing, a stratum pressure simulator with maximum pressure up to 35 MPa were development which can simulate the underground pressure of 3000 m depths. The rock samples were exploited from the sandstone mines and manufactured to a cubic block with a size of 0.4 m × 0.4 m × 0.4 m, a vertical borehole with a diameter of 0.05 m and a depth of 0.2 m was drilled in the center. Initial experimental results shown that more electric pulses are needed to generate the distinct fracture at the confining pressure, the height of crack is decreased with the increment of the confining pressure.