【摘要】 为了明确地下地震动幅值的衰减规律,基于日本最近几年发生的16次强烈地震的443组深井地震动记录,主要考虑分量方向和震级的影响,分析了地下深层(-100~-400m)地震动加速度幅值与地表对应幅值比(Ad/A0)以及竖向与水平向加速度幅值比(Av/Ah)沿深度的变化特征。结果表明,深层地震动加速度幅值比与深度大致呈线性关系,幅值比(Ad/A0)随深度的增加变化不大,主要分布在0.2~0.4之间;震级对幅值比(Ad/A0)有一定的影响,表现在震级变大幅值比有减小的趋势;另外,水平向加速度幅值比略小于竖向幅值比。竖向与水平向加速度幅值比(Av/Ah)沿深度也大致呈线性关系变化,且稳定在0.6附近。发现拟合关系式的选取会对结果产生较大的影响。最后,讨论了地下工程结构设计地震动加速度幅值的深层取值问题,以期为地下设计地震动参数的选取提供参考。更多还原

【Abstract】 Aiming at the nature of amplitude attenuation of under-ground motion with depth,443 groups of strong motions on surface and in deep(-100～-400m) underground recorded from 16 recent earthquakes with large magnitude in Japan are included in the analysis.The variations of ground motion acceleration amplitude ratios(acceleration at a depth to a corresponding amplitude of the surface,Ad/A0 and amplitude of the vertical-to horizontal-component,Av/Ah) with depth are evaluated by considering mainly the influences of component direction and magnitude of the earthquakes.It concludes that the acceleration amplitude of deep ground motion varies linearly with depth,and the amplitude ratio distributes mainly within the range of 0.2～0.4.Amplitude ratio(Ad/A0) is related to earthquake magnitude,and the ratio value shows a decreasing trend as the magnitude increases.Amplitude ratio of the horizontal direction is smaller than that of the vertical one.The ratio of Av/Ah also varies linearly with depth and keeps consistently a ratio value of 0.6.It is found that the regression formula being used could influence the results of seismic accelerations.Lastly,values of input ground motion of seismic design for deep underground structures is discussed.It is believed that this work will be useful for determining ground motion parameters of embedded structures in the seismic design.更多还原