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为探究黄土地区地下两层岛式地铁车站的地震动力响应,以西安地铁5号线的某车站为背景,采用摩尔G库伦本构条件和黏性吸收边界,建立三维有限元模型,分析了地震荷载作用下,地铁车站顶板、底板相对位移以及梁、侧墙、中柱的受力情况.结果表明:地震作用下,顶、底板相对最大位移随着埋深的增加而增大,换乘节点处的相对位移较大,可能发生错位;随着埋深增加,梁的最大轴力从均匀分布逐渐向着梁交叉处集中,梁的最大剪力产生在梁的末端,且换乘节点处的梁剪力较大,易产生裂缝;侧墙边角处剪力与弯矩均达到最大值,出现应力集中,易出现破坏,甚至坍塌;中柱轴力最大值产生在车站的换乘节点处,最大剪力产生在车站两端.岛式地铁车站的换乘节点处发生横截面突变,地震响应突出,因此应该作为抗震设防的重点.
In order to explore the seismic response of two underground railway stations in the loess area, a three-dimensional finite element model was established based on Mohr-Coulomb constitutive conditions and viscous absorption boundary using a station on Xi’an Metro Line 5. Under the action of load, the relative displacements of roof and floor of metro station, as well as the stress of beam, side wall and center pillar, the results show that under earthquake, the relative maximum displacement of roof and floor increases with the increase of buried depth, With the increase of depth, the maximum axial force of beam gradually converges toward the intersection of beams, the maximum shear force of beams is generated at the end of the beam, and the beam at the transfer node The shear force is large and the cracks are easy to be generated; the shear forces and bending moments at the corner of the side wall reach the maximum value, the stress concentration occurs, the damage or collapse is liable to occur; the maximum axial force of the column produces at the transfer node of the station, The maximum shear force is generated at the two ends of the station.As a result of the sudden change of cross-section at the transfer node of the island metro station, the seismic response is prominent, so it should be the focal point of seismic fortification.