关键词: 地震峰值加速度, 场地指数, 场地效应, 定量关系, 山东地区

Abstract:

Site effect on seismic peak ground acceleration is widely considered in such fields as seismic ground motion parameter zonation, earthquake early warning and quick assessment of seismic damage losses. Documents on seismic safety evaluation of engineering sites, including site type, overburden thickness, shear wave velocity, calculated seismic peak ground accelerations on both rock and soil surface for 2 630 engineering sites in Shandong Province have been collected in this paper. On the basis of these data, site amplification factor and site index for each site have been calculated. The site index is an integrated index to characterize the site condition and is computed from the shear wave velocity, density and thickness of the cover layers. Its values may change from 0 to 1. With the method of regression analysis, the relations among the site amplification factor, peak acceleration of bedrock and the site index are studied. A quantitative statistical relation between site amplification factor and other parameters is achieved. The site amplification factor in this paper is expressed as functions of peak acceleration of bedrock and site index, thus, its value may change continuously with the changing of the other parameters. The statistical relation for the site amplification factor in this paper is acquired on the basis of numerous, widely distributed data in Shandong Province, especially, site conditions can be represented in detail with site index. Therefore, the acquired statistical relation could characterize the changing scenarios of the site amplification factor with both the peak acceleration of the rock surface and the site condition details. The results show that the site amplification factor is negatively linearly related with the rock surface seismic peak ground acceleration and nonlinearly related with the site index.

Key words: seismic peak ground acceleration, site index, site effect, quantitative analysis, Shandong area