Concrete monolith splitting off by multi-borehole electro-blast

Summary form only given. The method of monolith splitting off and fracture of oversized concrete lumps by pulsed electrical discharge is presented. The pulsed power generator with stored energy up to 63 kJ and electro-explosive polyethylene cartridge with wire for discharge initiation
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are described. The experimental data of multi-borehole and step by step monolith splitting off with using of the polyethylene cartridge are given. The simultaneous initiation of discharge in two boreholes with 30 cm spacing, transferred energy in each borehole ~23 kJ and sequential initiation of discharge with transferred energy in one borehole 47 ~kJ are investigated. The concrete splitting off with dimensions of 300×300×300 mm by the four boreholes and the total energy ~100 kJ take place. It is shown that multi-borehole initiation of the electrical discharge leads to the cracks formation in predefined direction and to the directional solid splitting off. The experimental results shown that the multi-borehole electro-blast method in comparison with step-by step one has advantage in consumed energy.