TLM-CFSPML for 3D dynamic responses of a layered transversely isotropic half-space

• Published in: Computers and geotechnics 2024-04, Vol.168, p.106131, Article 106131
• Main Authors: Li, Hui, He, Chao, Gong, Quanmei, Zhou, Shunhua, Li, Xiaoxin, Zou, Chao
• Format: Article
• Language: English
• Subjects: Elastodynamics; Fundamental solution; Perfectly matched layer; Thin layer method; Transverse isotropy
• ISSN: 0266-352X; 1873-7633
• DOI: 10.1016/j.compgeo.2024.106131

The perfectly matched layer (PML) has proven to be efficient for absorbing elastic waves in the unbounded domain. This strategy is frequently coupled with the semi-analytical approach, such as the thin layer method (TLM), to simulate wave propagation in a layered half-space subjected to dynamic sources. However, beyond spurious reflections due to discretization and zero-frequency singularity, traditional PML may cause exponentially increasing backpropagation waves attributed to material anisotropy when simulating transversely isotropic (TI) media, resulting in significant computational errors. This paper explores the coupling of the complex frequency shifted perfectly matched layer (CFSPML) with the TLM to provide a highly efficient and accurate tool for modelling wave propagation in a layered TI medium. The 3D fundamental solution for a dynamic point source acting on a multi-layered TI half-space is therefore derived. Numerical cases are conducted to evaluate the performance of the TLM-CFSPML in comparison to the TLM-PML. Various factors such as the material anisotropy, stiffness, load and observation positions, and loading frequency are systematically considered. The numerical results demonstrate that the CFSPML can address the computational instability issues related to the anisotropy of the medium. The TLM-CFSPML exhibits computational stability with all the considered scenarios while maintaining high computational efficiency.