基于强震监测记录的冶勒大坝动力反应特性初步分析

Preliminary Analysis of the Dynamic Response Characteristics of Yele Dam Based on Strong Motion Records

冶勒沥青混凝土心墙堆石坝最大坝高为124.5m,坝址区地震烈度高,地质条件复杂。大坝上布设了9台强震仪组成的强震监测台阵,自2005年12月开始投入运行至2014年12月底共获得有效记录57次,其中包括汶川地震、攀枝花地震和芦山地震记录。对典型强震记录进行时域分析和频谱分析,初步总结了冶勒大坝的动力反应特性。研究结果表明,大坝坝顶部位的动力反应主要以放大为主,并且随着底部PGA的减小,坝体放大倍数明显增大;由于地震动本身震源特性、传播途径的差异,大坝在不同地震中动力反应的频谱特性明显不同,但多次记录均显示土石坝体有较为明显的滤波作用。

Yele Dam is a rockfill dam with an asphaltic concrete core wall and a maximum height of 124.5m.The geological conditions around the area are fairly complex and present high seismic intensity.The earthquake monitoring station,which consists of nine strong motion seismographs,obtained 57 seismic response records from May 2005 to December 2014,including those of recent earthquakes,such as the Wenchuan earthquake,the Panzhihua earthquake,and the Lushan earthquake.Time domain and spectral analyses were carried out based on the monitoring data,and some dynamic response features of Yele Dam during these earthquakes were preliminarily summarized.The results showed that the dynamic response of the dam crest was amplified in most earthquakes and that the amplification factor obviously increased with decreasing PGA in the dam bottom.Because of differences in earthquake source characteristics and transmission routes,the spectral features of the dam＇s seismic response during these earthquakes significantly differed.All of the records indicate that the earth and rockfill dam exert obvious filtering effects on earthquake waves.