CAJ | 학술논문

针对一典型砂土场地基于等效线性分析方法，研究了土层对输入近断层地震动脉冲特性的影响。选取两组近断层脉冲和非脉冲地震动对地表加速度反应谱放大系数进行了对比研究。结果表明：基岩非脉冲地震动经过土层的高频滤波作用传至地表后有转换成脉冲地震动的可能；基岩脉冲地震动经土层传播至地表后仍具有脉冲特性，部分含有潜在第二脉冲的地震动由于共振作用会产生附加脉冲。与非脉冲地震动相比，脉冲地震动会引起土层较强的非线性响应，导致加速度反应谱放大系数随基岩加速度值的增大衰减较快；而对于长周期加速度反应谱(3 s)，脉冲地震动引起的放大系数在基岩加速度大于0.1 g 时远大于非脉冲地震动引起的放大系数。最后通过回归分析得到场地放大系数方程，建立了一种考虑近断层脉冲特性及土层非线性相互影响的场地概率地震危险性分析方法。
침대일전형사토장지기우등효선성분석방법，연구료토층대수입근단층지진동맥충특성적영향。선취량조근단층맥충화비맥충지진동대지표가속도반응보방대계수진행료대비연구。결과표명：기암비맥충지진동경과토층적고빈려파작용전지지표후유전환성맥충지진동적가능；기암맥충지진동경토층전파지지표후잉구유맥충특성，부분함유잠재제이맥충적지진동유우공진작용회산생부가맥충。여비맥충지진동상비，맥충지진동회인기토층교강적비선성향응，도치가속도반응보방대계수수기암가속도치적증대쇠감교쾌；이대우장주기가속도반응보(3 s)，맥충지진동인기적방대계수재기암가속도대우0.1 g 시원대우비맥충지진동인기적방대계수。최후통과회귀분석득도장지방대계수방정，건립료일충고필근단층맥충특성급토층비선성상호영향적장지개솔지진위험성분석방법。
This paper presents seismic response analyses,based on the equivalent linear method,of a sandy site subjected to near-fault ground motions.We investigate the effects of soil nonlinearity on the pulse characteristics of input ground motions,and explore the amplification factors for the spectral acceleration from near-fault pulse-like and non-pulse-like motions.We found that input non-pulse motions can be transformed into pulse-like motions by attenuating the high-frequency component as it propagates through the soil.The input pulse motion probably remains as a pulse characteristic,and tends to have multiple pulses when the input motion includes other potential pulses.The attenuation of the amplification factor,along with the spectral acceleration of the bed-rock motion,has a more significant effect on pulse-like motions than non-pulse motions.We ex-pect that this finding is related to the strong nonlinear response of the soil caused by the pulse ex-citation.However,the amplification factor for a long period(e.g.,3 s),when the pulse motion is greater than 0.1 g,is larger than that of a non-pulse motion.Finally,a probabilistic seismic hazard analysis (PSHA)procedure is proposed to incorporate the coupled effects of the near-fault pulse characteristic and the nonlinearity site response.