A new methodology for the simulation of tunnel rockburst due to far-field seismic event

Abstract

Dynamic disturbance from far-field seismic events is one of the main causes for triggering rockbursts in underground excavations. In this study, a comprehensive methodology for the simulation of a remote seismic source is proposed. The methodology encompasses the processing of raw seismic waveform based on the synchro-squeezing transform (SST) method and numerical modelling using finite-difference code FLAC3D. The main contributions of this study are as follows. First, the raw waveform is processed and reconstructed into P- and S- waveforms using the SST method, which is superior to applying synthetic waveforms in seismic modelling. Secondly, an innovative source waveform and material damping calibration procedure is put forward based on the empirical scaling law, producing a generalized seismic source waveform with input level of energy. Furthermore, a seismic loading scheme in numerical modelling is proposed; a spherical point source is created for applying P- and S- waveforms in different theoretical directions. Numerical modelling results show that the theoretical directionalities of P- and S- waves are well differentiated and reflected using the proposed dynamic loading method. The peak particle velocity (PPV) and peak kinetic energy density distributions around openings are interpreted, demonstrating that the proposed methodology could assist in rockburst risk assessment and dynamic rock support design