Analysis Of The Seismic Spectrum And Field Seismic Effect At Tianjin Coastal Soft Soil Region

The foundation at Tianjin coastal region is a typical littoral facies—the deposit soft soil of land cross the sea, but the spectrum of seismic wave is a major consideration of structure seismic design. Tianjin is only big city surrounding the Bahia sea, which located at Cenozoic sedimentation basin, and its foundation is made of thick sedimentary layer in the high salinity, high humidity Soft. This foundation has a unique spectral characteristic:the low-frequency ground motion and seismic ground deformation will be magnified, and the liberation time will be extension. This effect is very bad for high building and high—span structure, and this is a factor for increasing the damage. Therefore, the spectrum of seismic wave is one of critical problem for building seismic design. Analysis of the unique seismic wave spectrum at Tianjin coastal region and providing a scientific seismic design is a necessary method to reduce soft soil damage.At the same time, it's very representative to research on the soft soil at Tianjin coastal area, these typical area are the high speed construction area in China, even the world. and this make the study at these soft soil area high practical significant. This article rely on the project of scientific and technological innovation in Tianjin, and make use of the geotechnical investigation data, we build a Three-dimensional model to analyze the spectrum character by the non-linear at this region. We use the Chi-Chi wave,Qingping wave,EL Centro wave and Kobe wave as the input wave to analyze the wave changes under the effect of different spectrum character, and we discuss the site wave effect influenced by site condition and input wave spectrum character and intensity, and summarize some of the rules.To contrast the wave spectrum character changes at soft region, we also build a three-dimension model with the geotechnical data at Beijing, and we analyze the spectrum character at hard site, we also analyze the differences between soft soil and hard soil.At the same time, to contrast the differences structure response between soft soil region and hard soil region, we build two model according to the data at the regions, and provide an seismic fortification for project.