Calculating the attenuation of stress waves passing through an in situ stressed joint using a double nonlinear model

Abstract

In situ stress is a significant characteristic of underground rock masses. In this work, based on the time-domain recursive method (TDRM), a new theoretical approach is proposed to study the oblique propagation of an S-wave across an in situ stressed joint wherein the normal and shear deformations are both treated nonlinearly. Equations are first established for the propagation of stress waves across a rock mass subjected to a combination of gravitational and tectonic stress. The veracity of the wave propagation equations is then investigated by comparing our theoretical results with those obtained using the Universal Distinct Element Code (UDEC). A comparison of the waveforms predicted using the continuously yielding and existing models is also presented to investigate their differences. Finally, parametric studies are conducted to investigate the effects of joint angle, in situ stress, lateral pressure coefficient, and incident wave amplitude on the propagation of the wave. The results show that the effect of in situ stress on wave propagation is related to the joint angle and lateral pressure coefficient because these factors decide the initial stress and contact states of the joint.