Multi-borehole electro-blast method for concrete monolith splitting off

Abstract

The multi-borehole method of monolith splitting off by pulsed electrical discharge is presented. The experimental data of simultaneous and step by step discharge initiation for 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 about 23 kJ as well as sequential initiation of discharge with transferred energy in one borehole about 47 kJ are investigated. The concrete splitting off with the dimensions of 300×300×650 mm by six boreholes with step-by-step initiation in each borehole and with total energy of about 280 kJ as well as the concrete splitting off with dimensions of 300×300×300 mm by the four boreholes with simultaneous initiation in each two boreholes and the total energy of about 90 kJ take place. It is shown that the simultaneous 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 show that the simultaneous discharge initiation in comparison with step-by-step one has advantage in consumed energy.