刚性桩复合地基地震反应的拟静力计算方法

针对竖向传播的SV波作用下刚性桩复合地基的动力反应,在振型分解反应谱法的理论基础上,提出一种基于有限元分析的拟静力方法。该方法通过等效线性方法考虑土体的非线性,将上部结构惯性力和自由场变形对桩身内力的影响分开来考虑,其中前者采用类似振型叠加反应谱法的方法进行分析,后者采用一种针对地下结构的改进的有限元反应位移法进行分析。与动力时程分析的结果对比表明,所建议的计算方法能够较准确地求得水平地震作用下桩身内力峰值及其分布,显著提高了分析的效率。

Quasi-static calculation method for seismic response of rigid pile composite foundation

Based on the finite element method and the theory of mode superposition,a quasi-static calculation method for the seismic response of rigid pile composite foundation under SV wave is presented.The nonlinear behavior of the soil is considered by the equivalent linear method,and the influence of the inertia force of the super-structure and the deformation of the free field response on the internal force of the pile is considered separately.The former is analyzed by using the mode superposition method of response spectrum,and the latter is analyzed by using a modified FEM for seismic deformation of underground structures.It is found that both the peak values and the distribution of the force in the pile can be calculated satisfactorily by using the method proposed,and that the efficiency of calculation is greatly increased.