ANALYTICAL SOLUTIONS OF THE SCATTERING OF PLANE WAVES BY LOCAL SITES WITH SATURATED SOIL

摘要

The ground amplification effects caused by irregular surface topography and geological conditions have been the focus of research by both seismologists and earthquake engineers for the last three decades. Many methods have been developed. However, only few analytical solutions are available so far, and the majority of the solutions for the wave propagation are supposed in the single-phase elastic medium. In this paper, the earthquake ground motions of local irregular sites with saturated soil were investigated by analytical solutions, and a series of results were obtained. Firstly, on the basis of Biot dynamic theory, an analytical method for scattering of plane waves by saturated soil was developed using Fourier-Bessel series expansion technique.Using this method, a series of analytical solutions for scattering of plane waves by saturated soil local irregular site can be got. Secondly, on the base of the analytical solutions mentioned above, the numerical results were given to illustrate that the ground motions of the saturated soil local irregular site not only depend on the angle of incidence, the dimensionless frequency of the incident waves, but also depend on the saturation and porosity of the soil deposits, the stiffness and Poisson?s ratio of the solid-skeleton, and the boundary conditions. At the same time,the soft saturated soil site can be simulated by elastic one-phase solid model or by fluid-saturated porous media model, but the results of the ground motion by the two models were great different.