Seismic wave-field modeling of 3D irregularities in layered half-space under P-, S-, and Rayleigh waves with arbitrary incident azimuth

A finite element method (FEM) for simulating seismic wave fields of three-dimensional (3D) local irregular topography is proposed in this article. The author begins by developing a program to solve the seismic response of 3D layered foundations using the frequency-domain stiffness matrix method. This enables the user to easily obtain the input of ground motion for the finite element model, as well as conduct finite element simulations of the seismic wave field of incident P-, SH-, SV-, and Rayleigh waves coming in from any direction. This method solves the problem that previous 3D finite element modeling methods couldn't handle SV waves when the angle of incidence is greater than the critical angle. Furthermore, it effortlessly accounts for the dispersion properties inherent in layered foundations. A series of 3D seismic wave field simulation examples are employed to validate the method's accuracy. In the end, this method is subsequently applied to further investigate the seismic response of frame structures in sedimentary valleys, and the significance of soil nonlinearity and topographic effects on the seismic response of structures is presented.