天津滨海软土一维场地地震反应非线性分析研究

摘要

With the in-depth study of observation and analysis of the motions of site soil during earthquake,the distinct non-linearity and hysteretic response of the soil have been found in medium and large motions of the earth. For the changes of stiffness and energy dissipation observed in both laboratory tests or during earthquake,the present method of site response analysis cannot represent them simultaneously in calculating. This paper conducts a non-linear one-dimensional site response analysis by introducing a frequency-independent viscous damping matrix which can decrease the over-damping at high fre-quency. With the example of the computation of Tianjin coastal soft soil model by using the program DEEPSOIL,thepaper does a comparative analysis of the result of non-linear 1-D and that of the equivalent linear site response analysis,and draws the conclusion that in large strain the result of non-linear 1-D site response analysis is more accordant with the practical situation than that of the equivalent linear analysis.%随着对地震中场地土体振动的观察和分析的深入，土体反应在中、大地震动表现出的非线性和滞后性越加明显。对于土体场地反应分析实验中或者在记录的地震动中观察到的土体刚度的变化和能量的消散，现有的非线性场地反应分析方法不能同时在计算中表达出来。通过引用一个不依赖频率变化的黏性阻尼矩阵，借助滤频的方法在高频中减小过阻尼影响，对场地反应进行非线性计算分析。以DEEPSOIL计算程序计算天津滨海软土模型为例，分析比较使用该阻尼函数的一维非线性场地反应分析结果与等效线性分析结果，得出在大应变中非线性分析方法计算所得结果更符合实际情况。