【摘要】 综合各国核电站抗震设计规范对地震动输入界面土层剪切波速取值的要求,以理想化的水平成层软岩场地作为核岛场地,采用等效线性化模型考虑土的非线性动力特性,采用一维波传法研究了地震基岩面的选取对核岛场地地表地震反应的影响,结果表明:随着地震基岩面土层剪切波速的增大,场地地表PGA值相应增大;与理想基岩面输入地震动的地表PGA及地表加速度反应谱β谱相比,以剪切波速不大于700 m/s的土层作为地震基岩面是不合适的;以剪切波速2 400 m/s土层作为地震基岩面时,其地表峰值加速度偏小不大于15%、地表加速度反应谱β谱偏小不大于20%,不同地震基岩面的选取主要影响周期小于1.2 s的地表β谱,对周期大于2.0 s的地表β谱几乎没有影响。以剪切波速2 400 m/s土层为核岛场地地震效应分析的地震基岩面是合适的。更多还原

【Abstract】 Combined the shear wave velocity values of "seismic bedrock"interface of the nuclear power plant regulations from several countries,this paper presents a selection of the layered horizontal and idealized soft rock site as the nuclear island site. The equivalent linear constitutive model is established to represent the nonlinear dynamic characteristics of the soils. One-dimensional wave propagation method is used to study the effects of different depth"seismic bedrock"interface on ground surface seismic response of the soft rock site. The result shows that the peak ground acceleration of idealized soft rock site increases as the soil shear wave velocity value and the depth of "seismic bedrock"interface increase. Compared with the peak ground acceleration and the β spectrum curves of surface ground motion acceleration response spectrum under idealized " seismic bedrock" interface,it shows that the soil shear wave velocity value Vsof the "seismic bedrock"surface,which is less than 700 m / s,may not appropriate.When the Vsof the"seismic bedrock"surface is equal to 2 400 m / s,the corresponding lower approximate values of the peak ground acceleration and β spectrum curves are no more than 15% and 20% respectively. The soil shear wave velocity value and the depth of "seismic bedrock"interface have a significant influence on β spectrum curves when the periods are less than 1. 2 s,but have little influence when the periods exceed 2. 0 s. It is appropriate to select the soil with shear wave velocity value Vs2 400 m / s as the"seismic bedrock"interface for nuclear island site seismic effect analysis.更多还原