土层随机地震反应分析中侧向边界的影响分析

Effect of lateral artificial boundary on random seismic response of soil layer

研究了随机地震激励下土层地震反应及土-结构相互作用分析中有限土域的取值范围对计算精度的影响。分别以基岩白噪声谱和杜修力修正基岩谱作为输入,进行了土层随机地震反应分析,探讨了自由边界、固定边界和黏弹性边界3种人工边界条件下土域的取值范围、土介质阻尼和土体长深比(L/H)对土层随机地震反应的影响,给出了侧向人工边界合理位置的具体建议。在此基础上,选取土体的合理边界范围,建立土-结构相互作用分析模型,分别以基岩白噪声谱、杜修力修正基岩谱以及实测地震波功率谱作为输入,进行了土-结构相互作用体系随机地震反应分析,计算结果验证了侧向人工边界取值在土-结构相互作用体系随机地震反应分析中的有效性。

Under random seismic excitations,the precision of results with the scope of soil region in seismic response of soil layer and soil-structure interaction was analyzed.In this paper,with the bedrock white noise spectrum and Du Xiuli modified bedrock spectrum as excitations,random seismic response of soil layer was analyzed;and the effect of random seismic response of soil layer with three artificial boundaries（free boundary,fixed boundary and viscous-spring boundary）,damp coefficient and the ratio of width to depth（L/H） was discussed.Based on the above basis,suggestions of reasonable scope of lateral artificial boundary were given.At the same time,with the bedrock white noise spectrum,Du Xiuli modified bedrock spectrum and the power spectrum of seismic waves records as excitations,the random seismic response of soil-structure interaction was analyzed after the reasonable scope of soil selected and the model of soil-structure interaction established.The results show that the scope of lateral artificial boundary is satisfied for random seismic response of soil-structure interaction analysis.