Effects of the gradient distribution of microdefects on wave propagation through a rock mass

This paper investigates the effects of the gradient distribution of microdefects on wave propagation through a rock mass. A piecewise three-characteristic lines method is proposed that can consider the gradient distribution of microdefects. A rock mass with a microdefect gradient distribution was explored and compared to wave propagation through a rock mass with a uniform distribution of microdefects. Subsequently, the effects of gradient and frequency on the particle stress transmission coefficient, particle velocity transmission coefficient, and energy transmission coefficient were discussed. The results indicate that a rock mass with a microdefect gradient distribution significantly affects wave propagation. The traditional study of wave propagation in a rock mass with a uniform distribution of microdefects can be considered a special example of the present study. In addition, the particle velocity transmission coefficient and energy transmission coefficient are always less than 1.0. However, when the gradient is large and the frequency is small, the particle stress transmission coefficient is larger than 1.0, which shows that the particle stress amplitude in a rock mass with a microdefect gradient distribution will be amplified. •Wave propagation in a rock mass with a microdefect gradient distribution is studied.•A piecewise three-characteristics method is proposed in the present study.•The piecewise viscoelasticity of microdefects with a gradient distribution in rock is considered.•The effects of gradient properties on stress and velocity transmission are discussed.•The stress amplitude in gradient microdefect distributed rock can be amplified.