摘要
基于甘肃文县获得的汶川地震强余震记录分析和FLAC3D软件模拟场地地震反应的方法研究了地形条件对地震动的影响。首先结合文县流动地震台强余震记录,分析了文县山包场地的地震动分布特征;其次对该山包进行了地形测量、地震勘探和土样采取,根据实测资料建立了FLAC3D三维场地数值模型,采用实际基岩记录输入,研究了山包不同部位地震动的分布特征。研究表明:数值计算与观测的结果在一定频段范围内有较好一致性;其时域峰值加速度放大比接近,反应谱谱比结果放大趋势一致,1~10Hz的地震动放大最明显;FLAC3D软件能够有效地模拟三维场地的地震反应。
Combining the measured time history records of Wenchuan earthquake aftershocks in Wenxian County,Gansu Province and site earthquake response calculated by use of the software FLAC3D,influence of topographic conditions on ground motion was studied in this paper.Firstly,based on strong aftershocks' records of Wenchuan earthquake,elementary characteristics of ground motion at hill sites near Wenxian County town were analyzed.Moreover,combining topographic survey,seismic prospecting and collection of soil samples,this paper establishes a three dimensional site model by FLAC3D,and researches distribution characteristics of ground motion in the hills.Finally,the following conclusions can be drawn:the result of the calculations is close to the observations within a certain freguency band,especially for the amplification ratio of the peak ground acceleration and the spectral ratio of the response spectrum,the frequency range with most obvious amplification is 1-10 Hz;Three-dimensional seismic response can be simulated effectively by software FLAC3D.
引文
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