砂卵石地层不同结构型式大跨无柱地铁车站的抗震动力响应分析

针对砂卵石地层条件下不同结构型式的大跨无柱地铁车站,依托成都轨道交通某无柱车站,运用有限元软件和时程分析法进行抗震计算,对比分析了不同结构型式下车站的抗震动力响应。相比于矩形平顶直墙结构,无柱车站起拱可显著优化结构受力,其弯矩值可减少约35%,受力性能显著提升,具有较好的抗震特性;拱顶不同矢跨比对结构内力及层间位移角影响的敏感性分析表明,随着结构矢跨比增大,结构层间位移角呈递减趋势,当结构矢跨比接近0.25时,层间位移角降幅趋于平缓。不同结构型式车站的内力极值均出现于板墙相交位置,设计时应加强该处的抗震构造措施,以提高结构在地震作用下的抗剪和抗弯承载能力。

Seismic Dynamic Response Analysis of Large-span Non-column Metro Station with Differ-ent Structure Forms in Sandy Pebble Stratum

Aiming at the large-span non-columns metro station with different structural forms in sandy cobble stratum,a seismic calculation is carried out by using finite element method,the station seismic dynamic response with different structural forms are comparatively analyzed according to a station in Chengdu urban rail transit.The results show that compared with the rectangular flat-top straight-wall structure,the arching of non-column station can significantly optimize the structural stress and realize the large-span structure,the bending moment of which is decreased by 35%,indicating better mechanical and seismic behaviors.The sensitivity analysis of different sagittal span ratios that influence the internal forces of the structure and the displacement angle between layers shows that,as the sagittal span ratio of the structure increases,the displacement angle of the structure decreases,and when the sagittal span ratio of the structure is close to 0.25,the reduction of the displacement angle between layers tends to be gentle.Since the extreme value of internal force of different structural types of stations occurs at the intersection of slab walls,the seismic structural measures should be strengthened in the design to improve the shear and flexural bearing capacity of the structure under the earthquake action.