2013年4月20日Ms7.0芦山地震之后,我国数字强震动台网又捕获了千余组余震记录。本文采用强震动记录的水平向与垂直向的谱比法对触发的41个固定台站进行了场地特征分析,利用谱型特征和卓越周期对场地进行了初步的类别划分。通过对3个典型台站场地的钻孔资料对比讨论,表明强震动记录谱比曲线的谱型、卓越周期较好体现了台站的场地特征。与目前我国抗震规范中场地分类方法相比,本文采用的谱比法分类突出了场地的地震反应特征,与等效剪切波速等指标一样可作为描述场地特征的依据,这为进一步完善我国强震台站的场地特征提供方法。
The National Strong Motion Observation Network System of China has captured more than a thousand of aftershock records after the Ms7. 0 Lushan main shock on April 20,2013. This paper estimates the site effect of 41 fixed stations using the horizontal-to-vertical spectral ratio method,and gives the preliminary sites classification based on the shape of spectral ratio and natural period of the sites. The results show that the mean H / V amplification curve and the natural period can properly reflect the characteristic of site corresponding to the borehole profile of three different typical strong-motion stations. Compared with the site classification in Chinese seismic code,the spectral ratio method focuses on the seismic response,which is a valuable supplement to the traditional site parameters,such as equivalent shear wave velocity. The method could be referred to study the site characteristic of Chinese strong-motion stations.