Analysis of Seismic Waves Propagating through an In Situ Stressed Rock Mass Using a Nonlinear Model

Abstract

In situ stress is a significant characteristic of underground rock masses. This work extended the time-domain recursive method (TDRM) to study oblique wave attenuation across an in situ stressed joint wherein the normal and shear deformation behaviors were both treated nonlinearly. Employing the Barton–Bandis (B-B) and hyperbolic nonlinear (HN) slip models, equations were established for wave propagation across a rock mass under a combination of gravitational and tectonic stress. Then, the stress and displacement in the normal and shear directions were calculated under different in situ stresses for P- and S-wave incidence. The waveforms of the HN slip model and the Coulomb slip model were compared to investigate the differences therein and verify the wave propagation equation. Parametric studies were conducted to elucidate the influences of in situ stress, lateral pressure coefficient, angle of incidence, and amplitude of the incident wave. The results showed that the HN model depends on the stress history and shear stiffness degradation. The effect of the in situ stress on wave propagation depends not only on the gravitational and tectonic stresses but also on the direction of the particle vibration of the incident wave.