Simulated rockburst experiment: Numerical back-analysis of seismic wave interaction with the tunnel

This work presents a numerical back-analysis of seismic wave propagation from a simulated rockburst event. The aim was to compare the motions generated by a full-wave elastodynamic model, with the waveforms and regions of damage recorded in the experiment. This followed extensive forward analysis which is presented in a separate paper. A model of the artificial blast source, tunnel layout and recording positions was constructed. The results of the model are compared with seismic data recorded during the experiment, in terms of waveforms, amplitude decay, frequency, wave-types and regions of damage. Behaviour such as initial P-wave motions and effects on frequency are shown to be similar. Regions of high velocity and high tensile stress in the model correspond roughly with the area of observed damage. However, large damaging secondary wave motions are predicted which were not recorded in the experiment. Possible explanations are offered to explain this discrepancy after examining alternative models, including modifications to the source and introduction of failure on fractures. The results highlight both the potential for and the current limitations in applying forward models of seismic wave propagation to mining problems.