基于竖向台阵地震记录的场地地震响应分析

Site seismic response analysis based on vertical borehole array records

国内外已经建立许多井下台阵,并得到了不同深度处的地震记录。通过这些井下台阵地震记录,对真实场地进行土层地震响应的再现模拟分析,对完善土层计算模型和计算方法有很大帮助。本文提出了当采用竖向钻孔井下地震记录作为土层反应分析的输入地震波时,土层计算模型应选用刚性底边界,并利用日本千叶场地的竖向钻孔地震记录和钻孔剖面资料,采用等效线性化方法进行了土层地震响应模拟,通过与实测结果的对比表明:(1)当直接选取井下实测强震记录作为输入进行土层地震反应计算时,土层模型的底边界应该采用刚性边界;(2)对于本文选取的地震记录和钻孔剖面资料,土层地震响应等效线性化方法具有相当的精度。

Many vertical borehole arrays have been built in recent years, and the seismic records at different depths are obtained. Using these records, seismic responses for the real site can be simulated and represented, which are of great help to the improvement of soil response calculation model and method. In this paper, the first conclusion is drawn that when the borehole array records are used as the incident waves for soil layer seismic response analy- sis, the rigid bottom boundary condition should be used. Then by using the vertical borehole array records and borehole profile information of Chiba, Japan, soil seismic responses of this region are simulated by using the equiv- alent linear method. By comparison with the real records, it is shown that when the borehole array records are used as the incident waves for soil layer seismic response analysis, the rigid bottom boundary condition should be ap- plied. Besides, for the seismic records and borehole profile data used in this paper, the equivalent linear method for soil seismic response analysis has considerable accuracy.