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选取日本Kik-Net强震数据库中软(FKSH14)、硬(FKSH12)两类场地,建立场地概率模型。应用Monte Carlo技术随机生成50组场地剖面,分别计算场地的传递函数STF及STF标准差,讨论场地土层厚度、剪切波速,以及两者组合工况对场地传递函数的标准差的影响。结果显示:对于硬土场地,场地特征频率标准差相对于软土场地较大,且剪切波速变异性的影响略大于土层厚度变异性的,两者组合工况的影响最大;而对于软土场地,土层厚度、剪切波速变化工况下,场地特征频率的标准差相当,略低于两者组合工况;对于软、硬两类场地,土层厚度与剪切波速两者组合工况下的STF标准差略大于单一量变化工况,但3种工况下的场地STF标准差相差不明显;场地STF标准差在场地自振频率附近的频率段取值较大,极值点与场地STF的极值点相对应;基于实际地震记录的场地传递函数标准差高于模拟的结果,但是两者极值点对应的频率范围吻合。
The Kik-Net strong earthquakes database (FKSH14) and hard (FKSH12) were selected to establish the site probability model. The Monte Carlo technique was used to randomly generate 50 sets of site profiles. The STF and STF standard deviations of the site were calculated respectively. The influence of the site thickness, the shear wave velocity and the standard deviation of the site transfer function were discussed. The results show that the standard deviation of site characteristic frequency is larger than that of soft soil site and the effect of shear wave velocity variability is slightly greater than that of soil thickness, The standard deviation of site characteristic frequency is quite lower under the working conditions of soil site, soil thickness and shear wave velocity, which is slightly lower than the combination of the two conditions. For both soft and hard sites, the combination of thickness and shear wave velocity The standard deviation of STF under operating conditions is slightly larger than that of single unit, but the standard deviation of STF under the three conditions is not obvious. The STF standard deviation of site has a larger value in the frequency range near the natural frequency of the site, Point corresponds to the extreme point of the site STF. The standard deviation of the transfer function of the site based on the actual seismic record is higher than that of the simulation, but the frequency range corresponding to the extremum points of the two sites agrees well.