【摘要】 采用有限元方法在时域内研究了断层破碎带对地震动放大作用的基本规律,分析了破碎带宽度、破碎带刚度、破碎带倾角以及输入地震波频谱等对地震动放大作用的影响。研究表明:断层破碎带的存在对地震动有显著的放大作用,断层上盘地震动幅值明显大于断层下盘,地震动峰值出现在破碎带附近及断层上盘。破碎带上盘各点的反应谱卓越周期明显比较长,而破碎带下盘各点的反应谱卓越周期则比较短。破碎带宽度越大,地表水平加速度反应谱幅值越大。刚度越低,地表水平加速度反应谱幅值越大。随着破碎带倾角的增大,反应谱峰值的最大值位置逐渐向破碎带上盘方向偏移。断层破碎带对地震动的放大作用与输入地震波频谱也存在着密切的关系。更多还原

【Abstract】 This paper investigates the amplification of seismic ground motion around fault fracture zone using finite element method in time domain,and discusses the effect of the width,stiffness and inclined angle of fault fracture zone and the spectrum of incident seismic waves on the amplification of seismic ground motion.It is shown that,fault fracture zone can significantly amplify the seismic ground motions nearby.The seismic ground motions at upper wall of a fault are larger than those at lower wall of the fault,and the PGA(peak ground acceleration) appears around fault fracture zone and upper wall of the fault.The predominant periods of response spectra at the upper wall of a fault are apparently longer,and those at the lower wall of the fault are shorter.The wider the fault fracture zone is,the larger the PRS(peak response spectrum) of horizontal seismic ground motion is;and the stiffer the fault fracture zone is,the larger the PRS of horizontal seismic ground motion is.As the inclined angle of a fault increases,the position of the maximal PRS gradually moves to the upper wall of the fault.The spectrum of incident seismic wave also plays an important role in the amplification of seismic ground motion around a fault.更多还原