分体柱在地下车站结构中的减震效果研究

Seismic mitigation effects of split columns in underground station structures

已有研究表明,对于浅埋框架式地下结构,高轴压下中柱水平变形能力不足是导致地震破坏的关键因素。分体柱在承载能力与整体柱相当的情况下,具有更好的变形和耗能能力而广泛应用于地上结构,探讨了分体柱在地下结构抗震领域中的应用可行性。基于ABAQUS有限元平台,建立土–地下结构整体三维数值分析模型,通过Pushover和动力时程分析方法对比研究了采用分体柱的新型地下车站结构与原型车站结构的抗震性能,分析了分体柱的减震效果。研究结果表明,采用分体柱的新型地下车站结构中柱的层间位移地震响应有所增大,但相对于中柱变形能力的提升,其影响程度并不显著;分体柱替换现浇整体柱,会使得结构截面内力重分布,中柱所承担的剪力大幅减小,侧墙的剪力变化不明显。总体上,采用分体柱的新型地下车站结构显著改善了在高轴压比下中柱和侧墙变形不协调的问题,能够有效提升其抗震性能。

It has been shown that the lack of horizontal deformation capacity of the middle columns under high axial pressure is the key factor leading to seismic failure of shallow frame underground structures. When the bearing capacity of the split columns is equal to that of the whole columns, the split columns have better deformation and energy dissipation capacity. Based on ABAQUS finite element numerical analysis, by establishing a three-dimensional numerical model for soils and underground structures as a whole, the Pushover analysis method and the dynamic time history analysis method are used to compare and study the dynamic response differences between the new underground station structure and the prototype station structure. The research results show that the seismic response of the story displacement of the new underground station structure with split columns increases, but the influence degree is not significant compared with the improvement of the deformation capacity of the columns. The replacement of the cast-in-place integral columns with the split columns will make the internal force of the structure section redistributed, the shear force borne by the middle columns greatly decreases, and the change of the shear force of the side walls is not obvious. On the whole, the new type of underground station structure with split columns can significantly improve the incoordination of deformation between the middle columns and the side walls under high axial compression ratio, and can effectively improve their seismic performance.