Characteristics of capillary discharge channel and its effect on concrete splitting-off by electro-blasting method

5th International Congress on Energy Fluxes and Radiation Effects 2016

Kuznetsova, N.S.^1 ; Yudin, A.S.^1 ; Voitenko, N.V.^1

Institute of High Technology Physics, Tomsk Polytechnic University, 30 Lenin avenue, Tomsk

634050, Russia^1

关键词: Capillary discharges;    Discharge initiation;    Electrical energy;    Operating voltage;    Reflected pressure;    Shock-wave dynamics;    Tangential stress;    Wire applications;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/830/1/012043/pdf
DOI  :  10.1088/1742-6596/830/1/012043

来源: IOP

【 摘 要 】

The numerical simulation results on fracture of a concrete block due to dynamic explosive loads applied to the walls of a blast hole are presented. The influence of the pulse shape on the shock-wave dynamics is considered. A comparison of mechanical stresses in direct and reflected pressure waves induced in the concrete block by explosion pulses of various durations and amplitudes shows that the shorter pulses with higher amplitudes and steeper rise times provide a higher blasting efficiency. The wire application for the discharge initiation enables the operating voltage of the generator to decrease, the discharge gap to increase, and hence, the channel energy to lead to the demolition build-up at electro burst. The significant dependence of the stress-wave profile on the pressure pulse wave shape at the borehole wall, which is determined by the rate of electrical energy release in the plasma channel, has been shown. An analysis of the stress-wave dynamics has shown that the rapid power deposition into a plasma channel tends to shift an amplitude of the tangential stresses in a reflected wave to the higher values and to extend the region of tensile tangential stresses initiating the main crack propagation from the borehole walls to a free material surface.