基于我国现行规范场地划分标准的中小震地震动峰值加速度衰减关系

搜集了美国西部近几年的中小地震记录1 321条以及场地钻孔资料,震级范围为M(3.5~6.5),根据钻孔资料将美国西部地震记录,按照我国GB 50011—2010《建筑抗震设计规范》的规定进行场地分类,统计得到了Ⅰ、Ⅱ、Ⅲ类场地的地震动峰值加速度的衰减关系并分析了其特点。通过将Ⅰ类场地地震动峰值加速度的衰减关系与前人研究的基岩场地衰减关系对比,发现Ⅰ类场地得到的水平和竖向PGA衰减曲线与前人研究的基本一致。由此说明只要场地类别一致,使用不同地区同类场地的中小震记录进行地震动参数研究是可行的。结果为我国的中小震峰值加速度估计提供了依据。

THE ATTENUATION RELATION OF THE SMALL-MODERATE EARTHQUAKE' GROUND MOTION PGA BASED ON CLASSIFIED SITE CRITERION IN CHINESE CURRENT SEISMIC DESIGN CODE

In this paper,the boring data and 1 321 small-moderate recordings in the western United States in recent years were collected,the magnitudes range M3. 5 ~ 6. 5,and the small-moderate recordings with boring data were classified by the criterion in the Code for Seismic Design of Building( GB 50011—2010) in China,the attenuation relations of peak ground acceleration in sites category Ⅰ,Ⅱ and Ⅲ were obtained and their characters were also analyzed. Which were compared with others' attenuation relation of the rock sites,it was found that the horizontal and vertical PGA attenuation curve in site categoryⅠshall was basic ally accordance with others' results. So as long as category of site was the same,studying the ground motion parameter was feasible by using small-moderate motion records in different areas. The attenuation relations obtained provided a basis for estimation of the small-moderate PGA on various sites in China.