A coupled method to study blast wave propagation in fractured rock masses and estimate unknown properties

The prediction of blast-induced ground vibrations across fractured rock masses is of great concern to rock engineers in evaluating the stability of rock slopes in open pit mines. Hence, many researchers have studied the wave propagation through rock slopes and tried to simulate its complexities using different methods. At the present work, the ‘linear superposition method’ was used at the Gol-e-Gohar iron ore mine to simulate the production blast seismograms based upon measurements of single-hole shot vibrations, carried out at a distance of 39 m from the blast. The production blast seismograms were then used as the input to predict particle velocity time histories in the mine wall using the three-dimensional discrete element method. By back analysis of measured blast waveforms at a distance of approximately 300 m away, mechanical properties of in-filled faults of the study area were determined. In combination with the numerical model, a ‘simulated annealing’ search algorithm was employed to find the optimum values of unknown parameters. The final results of time histories of particle velocity show a good agreement with the measured time histories.