Numerical modeling of seismic wave propagation and ground motion in underground mines

摘要

Dynamic rock support plays a critical role in ensuring mine safety and its design depends on several key design inputs. For rock support design and forensic analysis of rockburst damage, it is important to understand seismic wave propagation and ground motion distribution near excavation boundaries for seismic waves generated from a remote fault slip seismic event. This study aims at achieving a better understanding of wave propagation patterns around mine tunnels and capturing ground motion (Peak Particle Velocity - PPV) accurately for dynamic support design and forensic analysis. An advanced seismic wave propagation modeling tool, SPECFEM2D, is used to study complex wave propagation in underground mines. Attentions are paid to studying the influence of different mine excavations and geological structures on wavefields and ground motions near excavation boundaries. The simulation results show that the wavefields and the ground motion distributions become more complicated as more mine excavations and geological structures are involved. Moreover, the PPV distribution around a tunnel can be altered, leading to high and low PPV zones around the tunnel. In addition, modulation of travel time and long S-coda waves can be observed in the complex seismograms. Using the modeling approach, areas in an underground mine that may experience high potentials of rockburst damage could be identified and mine safety could be improved by implementing dynamic rock ground support in these areas.