Time-Domain Analysis of Underground Station-Layered Soil Interaction Based on High-Order Doubly Asymptotic Transmitting Boundary

Based on the modified scale boundary finite element method and continued fraction solution, a high-order doubly asymptotic transmitting boundary (DATB) is derived and extended to the simulation of vector wave propagation in complex layered soils. The high-order DATB converges rapidly to the exact solution throughout the entire frequency range and its formulation is local in the time domain, possessing high accuracy and good efficiency. Combining with finite element method, a coupled model is constructed for time-domain analysis of underground station-layered soil interaction. The coupled model is divided into the near and far field by the truncated boundary, of which the near field is modelled by FEM while the far field is modelled by the high-order DATB. The coupled model is implemented in an open source finite element software, OpenSees, in which the DATB is employed as a super element. Numerical examples demonstrate that results of the coupled model are stable, accurate and efficient compared with those of the extended mesh model and the viscous-spring boundary model. Besides, it has also shown the fitness for long-time seismic response analysis of underground station-layered soil interaction. Therefore, it is believed that the coupled model could provide a new approach for seismic analysis of underground station-layered soil interaction and could be further developed for engineering.