The Seismic Response Analysis Of Three-Dimensional Terrain

It is of great importance to consider seismic response analysis of site soil for determining ground motion input mode of the upper structure and the safety estimation of earthquake resistant. Taking into account the actual field geometry and physical properties of this very complex study, the use of theoretical methods is difficult to obtain analytical solutions, while its indoor tests, it is difficult to simulate because the boundary conditions and some of the similar conditions are not met, it will affect the reliability of test results. Thus, the present study in the field, has become a mainstream method of numerical calculation, among which the finite element method is the method used most often. In this paper, Based on three-dimensional finite element method, Under uniform harmonic excitation, the rules and mechanisms of seismic response of site soil is studied, this made the following tasks:1. the seismic response analysis methods, the type of seismic wave and site soil are summarized; the seismic wave adjustment methods are discussed; the boundary forms of the finite element method and the reasonable of cell size in the seismic response analysis of site soil are studied.2. As the local geological conditions or local terrain conditions are different, the seismic responses are vary considerably. This paper mainly studies the differences of the seismic response of site soil in five site conditions, such as basin-shaped depression terrain, soft sedimentary terrain on the inclined rock surface, isolated hills terrain contacting mountain, deep canyon terrain, plane bump terrain on the mountain.The results showed that:basin-shaped depression terrain has the amplification effect or reduction effect to ground motions in local areas; soft sedimentary terrain on the inclined rock surface will exist in the uneven phenomenon of the local seismic response; isolated hills terrain contacting mountain, deep canyon terrain, plane bump terrain on the mountain have the amplification effect to ground motions in local areas, the magnification factor is related to the size and specific dimensions.