Two-dimensional scattering of plane waves by irregularities in a multi-layered transversely isotropic saturated half-space

Abstract Wave scattering of plane waves by irregularities in a transversely isotropic (TI) saturated half-space has been rarely studied. Based on Biot's theory, this paper used an indirect boundary element method (IBEM) to solve the two-dimensional (2D) wave scattering of incident plane qP1- and qSV-waves by irregularities in a layered TI saturated half-space. 2D dynamic Green's functions for uniformly distributed loads as well as pore pressure acting on internal inclined line in a layered TI saturated half-space are derived. The method was verified by comparing with two published results for isotropic medium. The canyon, partially filled alluvial valley and fully filled alluvial valley with trapezoidal cross-section are covered in numerical calculations. Results show that the dynamic responses of the three types of irregularities are significantly different. The peak surface displacement amplitude of the fully filled alluvial valley case is up to approximately twice as much as that of the canyon case. The influences of TI property on the three irregularities are apparent, and the soft sedimentary material is more sensitive to TI property. Besides, the ground motion of the local irregularities strongly affected by the incident angle and frequency of plane wave.