Two-Section Pulse Current Generator for Concrete and Rocks Destruction by Splitting Off

Abstract

The relevance of electro-discharge technology usage for construction and demolition work in dense urban areas is discussed. The technical possibilities and the equipment based on a two-section pulse current generator for multiborehole electro-discharge splitting off and destruction of rocks and concrete are described. Ways to increase the efficiency of electro-discharge solid materials destruction method are proposed. To increase the effectiveness of the crack initiation, the high-current pulse should have a high rate of rising edge (practically well-founded 3–7 kA/ $\mu \text{s}$ ). For crack propagation, the pulse duration should be as long as possible. (Good value is more than $500~\mu \text{s}$ .) Achievement of such controversial requirements in one generator is not a trivial task. To solve this contradiction and to increase the discharge circuit energy, the separation of the storage energy into two capacitor batteries as well as doubling the capacitance has been done. The inductance of $28~\mu \text{H}$ was installed in series with one battery section, which led to an increase in the channel energy release duration up to $400~\mu \text{s}$ . To increase the pulse duration even further, a pulse delay between two batteries was implemented. It is shown that in modes with a triggering pause between the batteries, the tensile stresses are formed earlier and covered almost all the distance from the borehole to the free border and acted on this space for a longer period of time.