| Soil seismic response and the spatial characteristics of seismic ground motions are important contents of the research in the field of earthquake engineering. In this paper, based on the existing research production, a numerical calculation method has been brought up to analyzing the scattering of three-dimensional soil to the SH wave, P wave and SV wave. The rationality of this method has been verified by comparing the numerical results with the analytic results; and I have investigated the characteristics of ground on condition that SH wave, P wave and SV wave incomes to the three-dimensional hemispherical canyon and alluvial valley by different incident angles. In this paper, the specific work contents are as follows.(1) A numerical analysis method of the three-dimensional scattering problem of seismic wave oblique incidence has been put forward. Using the transfer matrix method, to analysis the displacement response of the free field soil, and take it as the input of the boundary regions. Using the lumped mass finite element methods, to calculate the displacement of the internal nodes, and using artificial transmitting boundary to calculate the displacement of the boundary nodes.(2) Numerical simulation analysis of the dynamic response has been taken on condition that SH wave obliquely incomes to the three-dimensional sunken hemispherical valley, by comparing the results with the analytical results of J.Sanchez-Sesma we have verified the rationality of this method. Then I have compared the characteristics of the displacement reaction by different incident angles.(3) Numerical simulation analysis of the dynamic response has been taken on condition that P wave incomes to the three-dimensional sunken hemispherical valley, by comparing the results with the analytical results of J.Sanchez-Sesma we further verified the effectiveness of the proposed method. I have analyzed the displacement response and the dynamic magnification factor of the surface points by different incident angles of P wave, and clarified the necessity of considering oblique incidence.(4) Numerical simulation analysis has been taken on condition that SV wave incomes to the three-dimensional sunken hemispherical valley. I have analyzed the displacement response and the dynamic magnification factor of the surface points by different incident angles of SV wave.(5) Make a summary of the work of this paper, and put forward some further research suggestions. |
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