Study On Seismic Parameters For Important Projects Site

The reasonable earthquake ground motion input parameters are necessary to insure the correct designed results. However, nowadays, the response spectrum method does not take the influence of the temporal and spatial variability of the ground motion on the structure seismic response into account, and the ground motion frequency nonstationarity is not considered properly. Besides, there is in concordance in selecting acceleration peak in different domestic specifications. In this paper, some problems on the characteristics of ground motion acceleration peak, spatial variabilities and attenuation laws of the evolutionary power spectrum and the absolute elastic input energy equivalent velocity spectrum have been studied. Then, the methods of generating the scenario earthquake and synthesizing nonstationary strong ground motion have been discussed. Finally, the method was applied to determine the earthquake input parameters of Kezier dam site in Xinjiang. The main results of this paper are as following:(1) The calculated methods of effective peak ground acceleration (EPA) were put forward by analyzing the acceleration average magnified coefficient spectrum. The statistical results indicated that there was strong linear and logarithm linear correlation between peak ground acceleration (PGA) and EPA. The feasibility and rationality about using EPA to replace PGA were also demonstrated. The main effect factors on PGA, EPA and the proportion of PGA and EPA were discussed. The results suggested that the attenuation relationship, annual exceeding probability, the locations of site and potential earthquake sources and the maximum magnitude of potential earthquake source had directly influence on the value of PGA, EPA and PGA/EPA.(2) Based on the rock strong motion dataset in western North America, the attenuation relationships of evolutionary power spectrum and energy equivalent velocity spectrum were developed according to the similarity in geology, seismology and regional tectonics et al between China and western North America. The results revealed that models presented in this paper fitted the record's values better than those in correlative literature.(3) The method being used to analyze ground motion spatial variabilities by analyzing the influence of the variation of spatial distances on ground parameters was studied, and the stochastic prediction models were suggested as well. The results proposed that different parameters had different spatial distribution forms.(4) A scenario earthquake method which integrated the amplitude, duration and frequency of ground motion was presented. In this method, the dominant potential earthquake sources, which had the largest contribution to the site, were chosen from earthquake sources according to the EPA attenuation relationship. The magnitude and hypocentral distance of scenario earthquake were determined by energy equivalent velocity spectra attenuation relationship at 0.2 seconds periods within the dominant potential earthquake sources, and the specific...