基于双台阵模拟地震空间差动效应的模型箱参数解析
Analytical solution for design parameters of model box to simulate seismic spatial variability effect using double-array shaking tables
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摘要: 基于多台阵的地下结构振动台试验,需要借助模型箱的设计来实现地震空间差动效应的模拟,即通过模型箱将多台面离散差动输入转换为实际地震动连续差动输入。目前有关多台阵模型箱设计参数的选取尚无可参照的解析表达式或图表可循。针对典型的双台阵试验系统,建立双台阵模型箱的简化计算模型与荷载边界条件,基于积分变换和留数定理,推导出双台面输入条件下模型箱动力响应的解析解,直观给出模型箱动力响应与模型箱参数之间的解析关系。以实际地震动连续差动输入为目标,得到了基于双台阵模拟地震空间差动效应的模型箱参数解析表达式。最后通过多台面振动台空箱试验,验证了该模型箱参数解析表达式的正确性,可以用于指导基于双台阵模拟基岩面连续差动输入的模型箱设计。Abstract: Based on the multi-point shaking table tests on underground structures, the simulation of the seismic spatial variability effect can be realized by the design of model box, that is, the model container can be used to realize the equivalent transformation from the discrete multi-point shaking of the table into a continuous non-uniform seismic excitation. However, neither analytical solutions nor experimental data are available in the current literatures to obtain the design parameters of the model box. The simplified analysis model and boundary conditions of the model box are established for the typical double-array shaking table test system. According to the integral transformation and residue theorem, the analytical solution for dynamic response of the model box on the double-array shaking tables is derived, and thus the analytical relationship between the dynamic response and the parameters of the model box can be directly expressed from the proposed solution. By taking the continuous non-uniform seismic input as benchmark, the analytical expression for the design parameters of the model box is obtained. Finally, the proposed solution is verified by a series of shaking table tests. The analytical solution can be used for the design of the model box to simulate the seismic spatial variability effect based on double-array shaking tables.