考虑SSI的输电塔在地震摇摆分量下的响应研究

Study on the Response of Transmission Towers Under Seismic Rocking Component Considering SSI Effect

为研究土-结构相互作用下地震动摇摆分量对结构的影响,对土体-输电塔结构体系进行了理论分析和有限元计算。首先推导了摇摆分量和附加P-Δ效应影响下,考虑土体影响的输电塔结构的动力方程。其次,建立了基于子结构人工边界的地下摇摆地震动输入方法,完成了考虑土体影响的水平-摇摆耦合作用下地震动的输入,并以此以一实际的输电塔结构为基础,进行了考虑土体影响和摇摆地震动作用下的有限元计算。结合理论分析和有限元计算,得出以下结论:提出的摇摆地震动的输入方法能够准确地解决在考虑土-结构相互作用时的摇摆地震动的输入问题;动力方程体现出考虑摇摆效应和SSI效应后,输电塔结构的动力响应与未考虑时有较大差别;在利用改进的人工边界子结构法输入摇摆分量后,得出考虑摇摆地震动影响后,塔顶节点位移和加速度响应相较于单独地震水平分量作用时均会大幅增大;与刚性地基假定相比,考虑了土-结构相互作用之后,输电塔顶点位移响应将进一步增大。

In order to study the influence of the rocking ground motion on structure under soil-structure interaction,theoretical analysis and finite element calculation of soil-transmission tower structure system were carried out.Firstly,the dynamic equation of the transmission tower structure considering the influence of soil mass under the rocking ground motion and additional P-Δeffect was derived.Secondly,it was the input method of underground rocking ground motion which based on artificial boundary of substructure was established.The finite element calculation considering soil influence and rocking ground motion was carried out.Combined with theoretical analysis and finite element calculation,the results show that,the proposed input method can accurately solve the input problem of the rocking ground motion when considering soil-structure interaction.The dynamic equation shows that the dynamic response of transmission tower structure is significantly different from that without considering rocking ground motion effect and SSI effect.By using the improved artificial boundary substructure method to input the swaying components,it is concluded that compared with only considering the horizontal component,the displacement and acceleration responses of the tower top will increase substantially when considering the influence of the rocking ground motion.Compared with the rigid foundation assumption,the displacement response at the top of the transmission tower will further increase after considering soil-structure interaction.