周凤玺, 宋瑞霞. 2015: 平面P-SV波入射时非均匀饱和土 自由场地的响应. 地震学报, 37(4): 629-1267. DOI: 10.11939/jass.2015.04.009
引用本文: 周凤玺, 宋瑞霞. 2015: 平面P-SV波入射时非均匀饱和土 自由场地的响应. 地震学报, 37(4): 629-1267. DOI: 10.11939/jass.2015.04.009
Zhou Fengxi, Song Ruixia. 2015: Response of the non-homogeneous saturated foundation to incident plane P-SV waves. Acta Seismologica Sinica, 37(4): 629-1267. DOI: 10.11939/jass.2015.04.009
Citation: Zhou Fengxi, Song Ruixia. 2015: Response of the non-homogeneous saturated foundation to incident plane P-SV waves. Acta Seismologica Sinica, 37(4): 629-1267. DOI: 10.11939/jass.2015.04.009

平面P-SV波入射时非均匀饱和土 自由场地的响应

Response of the non-homogeneous saturated foundation to incident plane P-SV waves

  • 摘要: 基于Biot多孔介质波动模型,研究了非均匀饱和土层对平面P-SV波入射时的动力响应.考虑饱和土地基的物理力学特性沿厚度方向连续变化,利用亥姆霍兹矢量分解原理和动力刚度法,分析了平面入射P-SV波在非均匀饱和土层中的反射和透射,并给出了基岩表面和自由表面处反射系数和透射系数的计算表达式.基于理论推导结果,数值分析了平面SV波入射下非均匀饱和土自由场地的动力响应,其中假设饱和土地基的物理力学性质沿土层深度按幂律梯度变化.数值结果表明,平面SV波入射所引起的地面位移与基岩位移之比均随土层厚度和土体的非均匀程度、波的入射角和入射频率的增加而减小,且其竖向位移比的减小更为显著,厚土层对地震波的耗散作用尤为明显.

     

    Abstract: Based on Biot's model for saturated porous media,the dynamic responses of non-homogeneous saturated soil was studied by using Helmholtz vector decomposition principle and exact dynamic stiffness method (EDSM) when P-SV wave was incident from bedrock.Reflection and transmission of incident plane P-SV wave in non-homogeneous saturated soil were analyzed considering the continuous variation of physical and mechanical properties about saturated foundation along the thickness direction.As a consequence,the general calculation formulas about the reflection coefficient and transmission coefficient of bedrock and free-field on the both surfaces were given.As numerical examples,assuming that the material properties of the saturated foundation had an exponential law distribution and gradient variation along the thickness-coordinate,the dynamic response of non-homogeneous saturated soil and free-field to incident plane SV was discussed.The numerical results indicate that the ratio of ground displacement to bedrock displacement decreases with the increase of the thickness and heterogeneity index of saturated soil,incident angle and frequency of seismic wave.The vertical displacement ratio decreases more significantly than the horizontal one.The dissipation of seismic wave caused by the thickness of soil layer is obvious,which all should be taken into account in engineering practice especially on complex layered situations.

     

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