Parameters of a Series-Parallel Electrodetonator Network When Passing Tunnels

Abstract

The review of current research and scientific literature on the schemes of detonators’s electrical networks used in tunnel blasting operations was conducted. Based on the review, the goal and objectives of the study were set to construct typical dependences of physical quantities of a series-parallel electric detonator network on its parameters when passing through tunnels. The dependences of the current strength in the main wire and detonators of the electrical network from the parameters of the main wire at alternating voltages of 220 V and 380 V were established and constructed. Copper and aluminium cores fully provide the guarantee current in the main wire in the entire range of its parameters under study, regardless of the magnitude of the alternating voltage when passing through tunnels. Galvanized steel with a cross section of 1.1 mm² is not able to provide a guaranteed current with a main wire length of 1000 m and more and a voltage of 220 V, as well as with a main conductor length of 2000 m and more and a voltage of 380 V. The current strength in detonators is directly proportional to the current strength in the main wire and is smaller in magnitude. Reducing the alternating voltage from 380 V to 220 V leads to a decrease in the current strength in detonators, similarly to the main wire. Copper and aluminium wires provide a guaranteed current in detonators, regardless from the magnitude of the alternating voltage, the investigated length of the main wire and its cross-sectional area, except for a copper wire with a cross-sectional area of up to 1.2 mm² and a length of 2000 m or more at an alternating voltage of 220 V. Galvanized steel with a cross-section of 1.1 mm2 is not able to provide a guaranteed current in detonators with a main wire length of 300 m or more and a voltage of 220 V, as well as with a main wire length of 1000 m or more and a voltage of 380 V.