地下结构抗震设计的等效地震荷载动力有限元方法

Dynamic Finite Element Method for Calculating Equivalent Seismic Load in Seismic Design of Underground Structures

等效地震荷载是地下结构简化抗震设计方法的核心,直接决定简化方法的计算精度。目前,大多数简化抗震设计方法均围绕地震过程中土层的加速度响应或位移响应建立等效地震荷载。传统的土层地震反应采用等效线性化程序进行一维分析,难以反映土层真实的运动过程。基于大型通用有限元软件ABAQUS进行二维自由场地震反应分析,讨论了计算等效地震荷载的动力有限元方法,介绍了其建模过程及关键参数,并与等效线性化程序Edu Shake软件的计算结果进行对比。研究表明,动力有限元法的计算效果良好,可以运用于简化抗震设计时的等效地震荷载计算。

Equivalent seismic load is the core in simplified seismic design for underground structure,and directly determines the calculation precision of the simplified method. At present,most of the simplified seismic design methods build equivalent seismic loads around the acceleration responses or displacement responses of ground in an earthquake. Since the traditional ground seismic response adopts equivalent linear programs for one-dimension analysis,it is difficult to reflect the actual movement process of the ground. In this paper,a large general finite element softw are ABAQUS is used for a two-dimensional free field seismic response analysis. The dynamic finite element method is discussed,the modeling process and calculation of key parameters are introduced and compared with the calculation result of equivalent linear program Edushake softw are. The validity and accuracy of the proposed method is verified to be suitable for the simplified calculation of equivalent seismic load in seismic analysis.