Measurement and 2D Axisymmetric Modeling of Mining Blast-Induced Ground Vibrations

Abstract

Blast-induced ground vibrations are considered as an undesirable phenomenon resulting from productivity explosions in the extractive industries. Moreover, they are considered as a high potential cause for the damage of the surrounding structures. In this paper, the ground vibration data were recorded using a seismograph device at different distances from the detonation point in the quarry site of “Sococim Cement Factory,” which is located on Senegal. Thereafter, 2D axisymmetric numerical model has been established to simulate the propagation of the mechanical shock wave in the considered medium. The numerical modeling was developed under AUTODYN software, which is an explicit FEM code. First of all, the numerical model has been validated against the experimental measurements, by comparing the numerical and experimental longitudinal ($$V_{{\rm l}}$$) and vertical ($$V_{\mathrm{v}}$$) velocity signal at different gauges, for different equivalent explosive charges per delay ($$m_{\mathrm{eq(TNT)}}$$). A calibration was carried out only on the elastic properties of the rock to achieve this purpose. The adjusted values of K and G allowed to reproduce the numerical PPVs, in order to be in a good agreement with the measured PPVs. The energy dissipation due to the RHT model and the phenomenon of vibration’s damping as a function of time at the gauges locations is well reproduced by the numerical model. It is noted that the plasticity and damage near the borehole have no effect on the propagation celerity of the shock wave, which remains the same in the elastic medium. Furthermore, the damaged zone nearby the detonation point has been assessed and described by identifying the transition of limestone properties from the elastic–plastic to plastic-damage state. The characterization of the damaged zone, near the borehole for different explosive charges per delay, helps to calculate the face burden side and to enhance the blasting design.