液化场地装设粘滞阻尼器的桩基-结构体系抗震性能分析

Seismic performance analysis of pile foundation-structure system with viscous dampers in liquefiable soil

为了研究地震作用下粘滞阻尼器对液化场地群桩-土-结构抗震性能的影响。首先,基于OpenSees计算平台建立了液化场地群桩-土-结构三维有限元模型,并基于离心机试验结果验证了模型的可靠性。随后,选择Maxwell模型模拟粘滞阻尼器力学行为,并开展粘滞阻尼器参数敏感性分析,甄选适用于液化场地粘滞阻尼器减震设计的参数组合。最后,分析了上覆非液化土层对液化场地粘滞阻尼器减震设计的影响,对比了非液化与液化场地粘滞阻尼器减震设计的异同。研究表明:粘滞阻尼器能够有效减轻液化场地群桩-土-结构的地震响应,降低上部结构和柱墩底部的地震响应;上覆非液化土层改变了液化场地粘滞阻尼器减震设计适用值的范围;非液化与液化场地粘滞阻尼器减震设计的速度指数α适用值均是0.5~0.9,而阻尼系数C的适用值差异较大;相比于非液化场地,粘滞阻尼器在液化场地降低柱墩底部地震响应效果更好。研究结果可为液化场地群桩-土-结构的粘滞阻尼器减震设计提供重要依据。

To investigate the effect of viscous damper on the seismic performance of pile group-soil-structure in liquefiable soil under earthquake action.Firstly,build a three-dimensional numerical model of pile group-soil-structure in liquefiable soil by OpenSees finite element platform,and the reliability of the model is verified based on the centrifuge test results.Then,the Maxwell model was selected to simulate the mechanical properties of the viscous damper,and the parameter sensitivity analysis of the viscous damper was carried out to determine the suitable parameter value of the viscous damper under the condition of liquefiable soil.Finally,the influence of the overlying non-liquefiable soil layer on the damping design of viscous damper in liquefiable soil is analyzed,and the differences between the damping design of viscous damper in liquefiable soil and non-liquefiable soil are compared.The results show that the viscous damper can effectively reduce the seismic response of pile group-soil-structure system in liquefiable soil.It reduces the seismic response of the superstructure and the bottom of the pier.The overlying non-liquefiable soil layer affects the range of the optimal value of viscous damper in liquefiable soil.The suitable values of velocity exponentαof viscous dampers in non-liquefiable soil and liquefiable soil are 0.5~0.9,while the suitable values of damping coefficient C are significantly different.Compared with the non-liquefiable soil,the viscous damper can better reduce the seismic response at the bottom of pier in the liquefiable soil.The research results can provide an important basis for the design of viscous damper for pile group-soil-structure in liquefiable soil.