Attenuation assessment of blast-induced vibrations derived from an underground mine

摘要

Attenuation assessment of vibration induced by underground explosions is a source of concern due to its associated with damage analyses of underground facilities and ground structures. Based on the blast events at different levels of ore have different impacts on ground structures, to understand the attenuation rule of vertical propagation is essential for the safe design of mining blasts. In a new-built underground mine, eight seismographs were installed with different depths to monitor the blast vibrations, and 236 events included 24 events on the ground were recorded during mining production over a period of eight months. Certainly, the blasting design, propagating medium and its mechanical parameters were also carefully investigated. In the light of the collected data, various prediction equations are employed to establish a suitable relationship for describing the attenuations of peak particle velocity (PPV) and frequency. The charge weight effect on the frequency attenuation of the induced ground motion is also discussed. Moreover, the effect of surface soil overburden has also been analyzed based on a supplementary monitoring work. The results indicate that scaled distance (SD) with cube root scaling for the explosive quantity can properly perform the far-field vibration. Irrespective of how much the item of charge weight represents, its simplified form still makes the oldest equation still be widely used. The average frequency (AF) and its modified frequency equation perform well in the rock mass. The soil overburden has a low-impact on the ground motion, while the influence of charge weight per delay on ground wave frequency has diminished.