基于地基土等效线性的三维厂址反应分析

Three-dimensional Site Response Analysis Based on Equivalent-Linear Behavior of Foundation Soil

随着核电厂选址条件的日趋复杂化,土-结构相互作用(SSI)成为核电厂抗震分析需要考虑的重要因素之一。目前经典的自由场厂址反应分析采用的是一维层状地基土的分析,比如SHAKE91、EERA和SASSI等,很难考虑土层的非均质层状因素。因此随着核电安全的监管要求越来越高,抗震的精细化分析成为趋势。本文采用有限元程序ABAQUS编写的UMAT材料子程序,实现了基于地基土材料的等效线性,开展均质层状土的三维自由场厂址反应分析。其计算分析结果与SHAKE91计算结果进行对比表明,在均质层状土条件下吻合较好。因此,本研究为求解复杂非均质地基条件的SSI分析提供了良好的工程适用性。

With the increasing complexity of nuclear power plant's siting conditions,soilstructure interaction(SSI)has become an important issue to be considered in the seismic analysis.At present,the classical free-field site response analysis uses the analysis of one-dimensional layered foundation soil,such as SHAKE91,EERA and SASSI,so it is difficult to consider the heterogeneous layer factors of the soil layer.Therefore,with the increasing regulatory requirements for nuclear power safety,the refined analysis of earthquake resistance has become a trend.In this paper,the UMAT material subprogram written by the finite element program ABAQUS is used to realize the equivalent linearity of the foundation soil material and carry out the three-dimensional free-field site response analysis of the homogeneous layered soil.Comparing the calculation and analysis results with SHAKE91 calculation results,it shows that it is in good agreement under the condition of homogeneous layered soil.Therefore,this study provides a good engineering applicability for the SSI analysis of complex heterogeneous foundation conditions.