Reduction of tunnel blasting induced ground vibrations using advanced electronic detonators

Abstract

Blasting has been widely used for economical and rapid rock excavation in civil and mining engineering but has great loads, such as vibrations and noises, on the surrounding environment in the case of urban areas near dwellings and important structures. In this study, for the purpose of environmental load reduction, blasting tests were conducted at a tunnel construction site using advanced electronic detonators in which arbitrary ignition times could be set. The test results showed that the peak amplitude of the vibration waveform from each of the blast holes follows the Weibull distribution and that the wave propagation time depends on the location of the blast hole on the tunnel face. The superposition method proposed from these findings reproduced the vibration waveforms in delay blasting from the seed waveform recorded in single-shot blasting. The optimum delay interval determined accurately from the superposition method was almost equal to the one simply estimated from the method with the autocorrelation coefficient or a frequency analysis of the vibration waveform in single-shot blasting. These simple methods were validated at another tunnel construction site and found to be useful for estimating the optimum delay interval from single-shot blasting at each tunnel face on each day. This study is based on the practical consideration of actual tunnel blasting and construction, and these proposed methods will be widely applied to other tunnel construction sites.